What happened to Car Radio Antennas?

[Phil Allison]

Hi,

you may have noticed that few modern cars have any visible AM/FM antennas these days.
Many have a "shark fin" antenna on the roof for GPS and possibly 4G cell phones - frequencies used are similar.
Others have a short whip antenna somewhere, not much good for AM.

The answer ( found by Googling) is they often use the rear window "defroster" grid for AM and FM reception.
It can be made to work like a frame antenna for AM and a L shaped wire for FM. A booster amp is added near the window for impedance matching.

Some makers ( BMW ?) have two printed antennas on rear side windows that are boosted and fed into a selector unit that sends the stronger one to the receiver. This is called "antenna diversity" as is commonly used with radio mics.

If anyone knows more, make my day.


..... Phil

[Andy Burns]

Phil Allison wrote:

> Some makers ( BMW ?) have two printed antennas on rear side windows that are boosted and fed into a selector unit that sends the stronger one to the receiver. This is called "antenna diversity" as is commonly used with radio mics.

My ~15 year old Honda estate had in-glass aerials in the rear side
windows, Itwas AM/FM only (maybe LW too) but I do remember it picked up
'buzzing' when going under electricity pylons, probably just on MW.

Next car (audi) had DAB, I don't know where the aerial was, but it did
have a sharkfin, which seems like it was just for GPS which the car
didn't actually have.

Current car also audi has DAB and I believe the sharkfin is combined GPS
and DAB, reception is improved, but I think that's as much due to
in-fill in the DAB transmitter network here.

[Feather Duster]

Phil Allison <palli...@gmail.com> wrote:
> you may have noticed that few modern cars have any visible AM/FM
> antennas these days.

[snip]

> The answer ( found by Googling) is they often use the rear window
> "defroster" grid for AM and FM reception.

[snip]

> If anyone knows more, make my day.

1971 year Cadillacs [1] had at least their FM antenna as a pair of
wires embedded into the front windshield. They entered at the bottom
center, spaced about 1-2cm apart, and ran vertically in parallel up the
center of the windshield until about 3-4cm from the top, whereby each
turned 90 degrees from the other and ran horizontally in opposite
directions along the top of the windshield for about 0.3m or so each.

[1] Other nearby model years likely had the same, but I have no direct
knowledge of any of those years

[three_jeeps]

In the mid '70s (I believe), there were kits available that contained a thin wire antenna that was attached to single-sided clear tape that you could apply to the inside of the windshield. A leader was attached that was placed inside the A-pilar down to and then behind the dash to the radio.
I did a few installs on the family vehicles. Some vehicles are easier than others. The reception was mediocre on both AM and FM bands.

IIRC, my parents' 1992 Buick LeSaber had an antenna inside the windshield.
J

[bruce bowser]

I'm sure the car manufacturers could give you even more tricks about how to boost 5G transceiving.

[Michael Trew]

My '76 Chevy C10 pickup truck has two lines running up the center of the
windshield that split off -- this is the car antenna. Some parts on the
truck were from an '86 - so I can't prove if this was a feature from the
'86 or '76. I'd imagine it would make replacing the windshield a bugger
if you wanted to keep your antenna in working order.

[Phil Allison]

Michael Trew wrote:
================

>
> > If anyone knows more, make my day.
> >
> >

> My '76 Chevy C10 pickup truck has two lines running up the center of the
> windshield that split off -- this is the car antenna. Some parts on the
> truck were from an '86 - so I can't prove if this was a feature from the
> '86 or '76. I'd imagine it would make replacing the windshield a bugger
> if you wanted to keep your antenna in working order.

** All these alternatives to the time honored telescopic whip are compromised.

1. They are *directional* - complete null in two possible orientations.

2. Framed in a steel structure so partially Faraday shielded.

Guess having no ugly antenna sells cars to those who value cosmetics above results.
No wonder the are many "after market" alternatives available.


..... Phil

[Michael Trew]

Personally, I'd rather have a full whip antenna. I owned a '99 Chevy
(Geo) Metro that had a retractable one.

[Phil Allison]

Michael Trew wrote:
===============

>
> > ** All these alternatives to the time honored telescopic whip are compromised.
> >
> > 1. They are *directional* - complete null in two possible orientations.
> >
> > 2. Framed in a steel structure so partially Faraday shielded.
> >
> > Guess having no ugly antenna sells cars to those who value cosmetics above results.
> > No wonder the are many "after market" alternatives available.
> >
> >

> Personally, I'd rather have a full whip antenna. I owned a '99 Chevy
> (Geo) Metro that had a retractable one.

https://www.youtube.com/watch?v=KuZDVXhdYG8


.... Phil

[Rob]

Over here, the FM radio network was originally built with horizontal
polarisation. Maybe not much thought was spent on it, and it was done
just the same way as TV was done. Or maybe they had some valid reason
for it that did not work out as expected.

Anyway, that of course did not work well with typical car antennas of
the time. So at first, vertical polarisation was "added" to the
antennas (making it circular, I guess, depending on the phasing it could
also be slant polarisation). And later, when the antennas were
completely replaced because the contract to transmit FM signals went
from the incumbant telecom company to a commercial company, they
switched over to purely vertical polarisation.

Ironically, now the cars tend to have antennas that are more horizontally
polarized. But hey, they do not want us to use FM anyway.

[Phil Allison]

Rob wrote:
=======

>
> > If anyone knows more, make my day.
>

>> ... Phil

>

> Over here, the FM radio network was originally built with horizontal
> polarisation. Maybe not much thought was spent on it, and it was done
> just the same way as TV was done. Or maybe they had some valid reason
> for it that did not work out as expected.
>

** Not sure just where you are - but the same occurred in Aussie land in the mid 1970s.

> Anyway, that of course did not work well with typical car antennas of
> the time. So at first, vertical polarisation was "added" to the
> antennas (making it circular, I guess, depending on the phasing it could
> also be slant polarisation). And later, when the antennas were
> completely replaced because the contract to transmit FM signals went
> from the incumbant telecom company to a commercial company, they
> switched over to purely vertical polarisation.

** Initially all FM Tx was horizontal here.

It was expected that TV antennas would be the norm and FM car radios hardly existed.
In any case, the main broadcasters were classic music oriented so not so car listener concerned.

Then it changed, commercial broadcasters started up and went for circular antennas.

> Ironically, now the cars tend to have antennas that are more horizontally
> polarized. But hey, they do not want us to use FM anyway.

** Your average "invisible" car antenna tends to be horizontal.

Heinrich Hertz would not be amused ....



...... Phil

[Michael Trew]

Haha, not a power one. I can't remember the last time I've seen a car
with a power retractable antenna.

[Allodoxaphobia]

On Mon, 26 Jul 2021 23:54:40 -0400, Michael Trew wrote:
>>
>> Guess having no ugly antenna sells cars to those who value cosmetics
>> above results. No wonder the are many "after market" alternatives
>> available.

Similarly for Schmart Fones.
Selling either 'glitz' or 'cheap' wins hands down.
Audio fidelity comes in _far_ distant.

[Brian Gregory]

On 26/07/2021 06:44, Phil Allison wrote:
> you may have noticed that few modern cars have any visible AM/FM antennas these days.
> Many have a "shark fin" antenna on the roof for GPS and possibly 4G cell phones - frequencies used are similar.
> Others have a short whip antenna somewhere, not much good for AM.

I don't think a loop aerial on a car window would work at all well
surrounded by the much bigger thinker more conductive loop consisting of
the metal body of the vehicle in which the window is fitted.

I think it'd be better to just use it all as a short wire antenna much
like the short whips even for MW and LW.

But most cars nowadays only have FM and DAB+ anyway.

--
Brian Gregory (in England).

[Brian Gregory]

On 27/07/2021 09:26, Rob wrote:
> Over here, the FM radio network was originally built with horizontal
> polarisation. Maybe not much thought was spent on it, and it was done
> just the same way as TV was done. Or maybe they had some valid reason
> for it that did not work out as expected.

Horizontal polarization is supposedly attenuated slightly less over long
distance.

[Phil Allison]

** Google "power antenna" and you get hundreds of hits for new replacements.
Manual ones went out with the Dodo.

They always seemed to somehow get damaged....


...... Phil

[Phil Allison]

Brian Gregory wrote:
===============

> Phil Allison wrote:
>
> > you may have noticed that few modern cars have any visible AM/FM antennas these days.
> > Many have a "shark fin" antenna on the roof for GPS and possibly 4G cell phones - frequencies used are similar.
> > Others have a short whip antenna somewhere, not much good for AM.
>
> I don't think a loop aerial on a car window would work at all well
> surrounded by the much bigger thinker more conductive loop consisting of
> the metal body of the vehicle in which the window is fitted.

** Not true.
AM loops sense the magnetic field of the incoming EM wave.
Some are made from co-ax with the outer shield grounded to eliminate the E field.
Less static noise that way.
The nearby car bodywork has little effect on a window loop.


..... Phil

[Michael Trew]

One would think that the power ones would fail more easily.

[Michael Trew]

I've never seen a car with a radio without am AM tuner.

[Jeff Layman]

Perhaps that's the difference between the USA and Europe. I can't
remember seeing a car radio with MW here in the UK in at least the last
10 years - probably more like 20. Anyway, I miss the standard repair
sometimes seen here many years ago for telescopic antennas - a
"reshaped" wire coat hanger!

--

Jeff

[Andy Burns]

Michael Trew wrote:

> Phil Allison wrote:
>
>> Google  "power antenna" and you get hundreds of hits for new
>> replacements.
>> Manual ones went out with the Dodo.
>

> One would think that the power ones would fail more easily.

I suspect car-washes snapped off more manual ones, with power ones you
could switch off the radio if you realised.

[Phil Allison]

Michael Trew wrote:
===============

>
> > ** Google "power antenna" and you get hundreds of hits for new replacements.
> > Manual ones went out with the Dodo.
> >
> > They always seemed to somehow get damaged....
> >

> One would think that the power ones would fail more easily.

** The risk of damage far outweighed that.

FYI powered ones collapsed if the ignition or radio was off.


...... Phil

[Andy Burns]

Phil Allison wrote:

> FYI powered ones collapsed if the ignition or radio was off.

That's not how I remember (at leat some of) them ... inside the
telescopic sections was a coiled nylon(?) shaft, with teeth on the
outside that engaged with the metal parts, the shaft was motor-driven up
*and* down.

The aerial did retract when the ignition was turned off, but that was
deliberate, not simply by "falling down" because the ignition power to
it was cut.

[Phil Allison]

Andy Burns wrote:
==============

** ROTFLMFAO !!!!

FFS wanker.

The antenna drive unit was permanently powered from the battery.
The on-off switch on the radio triggered it to go up and down.
Micro switches told the DC motor when to stop.

The ignition key switch did the SAME !!!


..... Phil

[Andy Burns]

Phil Allison wrote:

>>> FYI powered ones collapsed if the ignition or radio was off.
>

> FFS

"collapsed" is very different from driven-down, IMO

[Phil Allison]

Andy Burns wrote:
==============

** Wow !

A folding telescopic object can be " extended" or " collapsed ".

Or did you image the antenna fainted ?



..... Phil

[Andy Burns]

Phil Allison wrote:

> A folding telescopic object can be " extended" or " collapsed ".
> Or did you image the antenna fainted ?

How should we know what type of third-rate shitty products you have to
put-up with down there?!

[Phil Allison]

Andy Burns is So Naive wrote:

=======================

** So we all now see your "extension " faints pretty easily ....




... Phil

[Rob]

Jeff Layman <jmla...@invalid.invalid> wrote:
>> I've never seen a car with a radio without am AM tuner.
>
> Perhaps that's the difference between the USA and Europe. I can't
> remember seeing a car radio with MW here in the UK in at least the last
> 10 years - probably more like 20.

Yes, that differs regionally. My car is 16 years old and it still has
MW and LW bands on the radio, but almost no stations on them anymore
here in Europe.

[legg]

I believe it was an anti-vandalism thing.

RL

[Ralph Mowery]

In article <slrnsg2jc3...@xs9.xs4all.nl>, nom...@example.com
says...

>
> > Perhaps that's the difference between the USA and Europe. I can't
> > remember seeing a car radio with MW here in the UK in at least the last
> > 10 years - probably more like 20.
>
> Yes, that differs regionally. My car is 16 years old and it still has
> MW and LW bands on the radio, but almost no stations on them anymore
> here in Europe.
>
>

It would depend where in the world one is. In the US cars started out
with AM only, then AM/FM, now many have the satalite added. There has
never been a MW/short wave radio on the standard American cars that I
know of. Not sure if you could even get the short wave radio on a
special order .

[Rob]

Here in Europe, what you Americans call AM is called MW (Mediumwave)
and we usually have a lower band called LW (Longwave). Both are using
AM modulation. But AM is too unspecific as a bandname because there
indeed may be additional bands on short wave (SW) that also would
be AM when on a car radio. There could be a couple of SW bands.
But SW on car radio is for special purposes and/or high-end radios
only, for countries where there is or was no local broadcast network
and you would listen to the international services of other countries.
Which mostly have shut down as well.

FM *is* used as a band name here, although of course it formally is
just as wrong as AM. However, FM usually refers to a 87-108 MHz band.
(in some countries that still may be different, e.g. it starts lower
in countries in the eastern block and Japan, and it used to end lower
in mainland Europe, first at 100, then at 104 and finally at 108 MHz)

[Ralph Mowery]

In article <slrnsg31dm...@xs9.xs4all.nl>, nom...@example.com
says...

>
> Here in Europe, what you Americans call AM is called MW (Mediumwave)
> and we usually have a lower band called LW (Longwave). Both are using
> AM modulation. But AM is too unspecific as a bandname because there
> indeed may be additional bands on short wave (SW) that also would
> be AM when on a car radio. There could be a couple of SW bands.
> But SW on car radio is for special purposes and/or high-end radios
> only, for countries where there is or was no local broadcast network
> and you would listen to the international services of other countries.
> Which mostly have shut down as well.
>
> FM *is* used as a band name here, although of course it formally is
> just as wrong as AM. However, FM usually refers to a 87-108 MHz band.
> (in some countries that still may be different, e.g. it starts lower
> in countries in the eastern block and Japan, and it used to end lower
> in mainland Europe, first at 100, then at 104 and finally at 108 MHz)
>
>

Yes, another difference in the contries. IN the US from about 600 to
1600 KHz is just commonly called AM. The exact frequencies have changed
slightly over the years. The FM is around 88 to 108 MHz. The shortwave
would be anything from about 1.8 to 30 MHz and mainly AM for the average
car or home listeners to comercial stations.

[Jeff Liebermann]

On Wed, 28 Jul 2021 12:44:29 -0400, Ralph Mowery
<rmow...@charter.net> wrote:

>Yes, another difference in the contries. IN the US from about 600 to
>1600 KHz is just commonly called AM. The exact frequencies have changed
>slightly over the years. The FM is around 88 to 108 MHz. The shortwave
>would be anything from about 1.8 to 30 MHz and mainly AM for the average
>car or home listeners to comercial stations.

AM/FM/MW/SW are stone age services. The trend is towards digital
everything. For example.

Satellite radio Sirius-XM:
<https://www.siriusxm.com>

DRM (digital radio mondiale):
<https://www.drm.org>

HD Radio:
<https://hdradio.com>

DAB (Digital Audio Broadcasting):
<https://www.worlddab.org>

AM Stereo:
<https://en.wikipedia.org/wiki/AM_stereo>

Get yourself an RTL-SDR receiver[1], a Raspberry Pi 3 Model B+ or
Mini-ITX computah, some mostly open source decoding software, and plug
the audio output into your existing AM/FM car radio.

You get most of the above digital radios services, the usual
AM/FM/MW/SW, and can add playing local digital media and cellular
streaming[2]. With a decent display, add ADS/B and AIR aircraft and
vessel tracking.


[1] <https://www.rtl-sdr.com/roundup-software-defined-radios/>
List and prices are about 5 years out of date.

[2] Free audio streaming on some T-Mobile plans:
<https://www.t-mobile.com/support/plans-features/unlimited-music-streaming-with-music-freedom>

--
Jeff Liebermann je...@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

[Jeff Liebermann]

On Wed, 28 Jul 2021 10:17:05 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:

>With a decent display, add ADS/B and AIR aircraft and
>vessel tracking.

Oops. That should be AIS, not AIR:
<https://www.marinetraffic.com>
<https://www.vesselfinder.com>

Distracted driving example:
Looks like Ever Given is out of Suez and almost in port at Rotterdam:
<https://www.vesselfinder.com/?imo=9811000>

[Phil Allison]

legg wrote:
--------------

>
> > Guess having no ugly antenna sells cars to those who value cosmetics above results.
> > No wonder the are many "after market" alternatives available.
> >
> >
> >..... Phil
> >
> I believe it was an anti-vandalism thing.
>

** Automatic, powered antennas did that perfectly.
For a fraction of the cost.

[Michael Trew]

Haha... a couple of my cars currently have the coat hanger trick... it's
nice to get stations again. I have a fleet now, but the newest one is a
'94.

[Michael Trew]

So is your MW band the same as our 540 to 1710 (1610 on older radios)
Kilocycles? Why did they drop those stations?

In the US, the "AM" dial is primarily talk radio, but there are still
music stations that I tune into.

[Michael Trew]

Eh, you can keep all of that fancy stuff. I won't pay for radio in my
car with a satellite subscription. I'm happy with my normal AM/FM bands
that I don't have to pay a dime for. Sometimes I'll play physical media
or hook up a MP3 player... one of my car radios accepts a USB flash
drive with MP3's on it.

[Phil Allison]

Rob wrote:
=========

> But AM is too unspecific as a bandname because there
> indeed may be additional bands on short wave (SW) that also would
> be AM when on a car radio.

** " AM band " is a perfectly accurate name.
The *only band* that is reserved for AM broadcasting.

> FM *is* used as a band name here, although of course it formally is
> just as wrong as AM.

** Wot drivel.

Again, it is the only band reserved for high quality FM broadcasting.


..... Phil

[Rob]

Jeff Liebermann <je...@cruzio.com> wrote:
> Distracted driving example:
> Looks like Ever Given is out of Suez and almost in port at Rotterdam:
> <https://www.vesselfinder.com/?imo=9811000>

Yes, it is unloading right now. Then it will go on to the Felixstowe (UK)
to offload the remaining containers and then it will dock for repairs.

[Rob]

Michael Trew <mt99...@ymail.com> wrote:
> So is your MW band the same as our 540 to 1710 (1610 on older radios)
> Kilocycles? Why did they drop those stations?
>
> In the US, the "AM" dial is primarily talk radio, but there are still
> music stations that I tune into.

Yes, MW is the 531-1602 kHz band (9 kHz raster) but we also had a LW
band 153-279 kHz, I think that is not used for broadcast in the US.

The stations were dropped because this is an inefficient way of transmitting
that has been replaced by FM, DAB+, mobile streaming via 4G/5G, etc.

Energy is expensive here and a typical radio station cannot pay the 100kW-1MW
power consumption of an AM transmitter.

[Rob]

Phil Allison <palli...@gmail.com> wrote:
> Rob wrote:
> =========
>> But AM is too unspecific as a bandname because there
>> indeed may be additional bands on short wave (SW) that also would
>> be AM when on a car radio.
>
> ** " AM band " is a perfectly accurate name.
> The *only band* that is reserved for AM broadcasting.

Maybe in the USA? Here we have/had at least two bands with AM broadcasting:

LW 153-279 kHz
MW 531-1602 kHz

And then of course there are various SW bands, e.g. the 49M band.

[Ralph Mowery]

In article <sdt89k$jao$5...@dont-email.me>, mt99...@ymail.com says...

>
> Eh, you can keep all of that fancy stuff. I won't pay for radio in my
> car with a satellite subscription. I'm happy with my normal AM/FM bands
> that I don't have to pay a dime for. Sometimes I'll play physical media
> or hook up a MP3 player... one of my car radios accepts a USB flash
> drive with MP3's on it.
>
>

That is my feelings also. I am not going to pay for satellite radio in
a car. Partly because I am not in the car enough to get much out of it.

I am not sure if I even have an AM radio in the house. I don't listen
to the FM stations either in the house. I use either the CD or USB
depending on the car to listen to music or other things.

[Ralph Mowery]

In article <slrnsg54p8...@xs9.xs4all.nl>, nom...@example.com
says...

>
> Maybe in the USA? Here we have/had at least two bands with AM broadcasting:
>
> LW 153-279 kHz
> MW 531-1602 kHz
>
> And then of course there are various SW bands, e.g. the 49M band.
>
>

As far as I know in the US the only bands for commercial radio has been
the frequency ranges of about 530 to 1700 KHz for AM and 88 to 107 MHz
for FM. Most radios will have only those 2 ranges on them that are
common . I know there are many that will have the short wave that
ranges from about 1.8 to 30 MHz on them but they are mostly imported
portable sets.

The US has never used the LW range of anything below about 530 KHz for
commercial transmtting.

The US did sponsor some Voice of America stations in the short wave
bands but they were mainly made to transmit to foreign countries.

[Rob]

Ralph Mowery <rmow...@charter.net> wrote:
> In article <slrnsg54p8...@xs9.xs4all.nl>, nom...@example.com
> says...
>>
>> Maybe in the USA? Here we have/had at least two bands with AM broadcasting:
>>
>> LW 153-279 kHz
>> MW 531-1602 kHz
>>
>> And then of course there are various SW bands, e.g. the 49M band.
>>
>>
>
> As far as I know in the US the only bands for commercial radio has been
> the frequency ranges of about 530 to 1700 KHz for AM and 88 to 107 MHz
> for FM. Most radios will have only those 2 ranges on them that are
> common . I know there are many that will have the short wave that
> ranges from about 1.8 to 30 MHz on them but they are mostly imported
> portable sets.
>
> The US has never used the LW range of anything below about 530 KHz for
> commercial transmtting.

Ok so in Europe that is completely different and in many countries any
radio that has MW would also have LW.
Not all countries had active transmitters there, or had them only for
a limited time, so e.g. here in the Netherlands you could find radios
that have only MW. But I have a French car and in France there are
several LW transmitters (or at least, there were). They tend to have
a longer range and are less affected by propagation changes. And of
course they often use ridiculous amounts of power and large antennas.
A wellknown LW transmitter in Warsaw, Poland had a half-wave vertical.
(646.38 metres or 2,120.7 ft). It collapsed during maintenance work.

> The US did sponsor some Voice of America stations in the short wave
> bands but they were mainly made to transmit to foreign countries.

Back in the days, the Netherlands had such a network as well.
Transmitters in 3 locations around the world sending information
in many languages, targeted to countries without or with unbalanced
information on radio.

But it has long been discontinued. Too costly, and replaced by Internet.

[Ralph Mowery]

In article <slrnsg5p80...@xs9.xs4all.nl>, nom...@example.com
says...

>
> Ok so in Europe that is completely different and in many countries any
> radio that has MW would also have LW.
> Not all countries had active transmitters there, or had them only for
> a limited time, so e.g. here in the Netherlands you could find radios
> that have only MW. But I have a French car and in France there are
> several LW transmitters (or at least, there were). They tend to have
> a longer range and are less affected by propagation changes. And of
> course they often use ridiculous amounts of power and large antennas.
> A wellknown LW transmitter in Warsaw, Poland had a half-wave vertical.
> (646.38 metres or 2,120.7 ft). It collapsed during maintenance work.
>
>

The US AM band of about 550 to 1700 KHz had lots of transmitters ranging
from about 250 watts to maybe 2000 watts. Many towns of populations of
30,000 or more peope often had atleast one and some two. The local town
to me had two. One was a 250 watt station and had a single antenna. The
other was a 1000 watt station and had 3 antennas about 50 or so meters
apart. During the day they broadcast with a directional patern that was
a circle. During the night they switched to a patern that was mostly
north and south. Those antennas were vertical towers that are about 90
meters or so high depending on the frequency.

During the day the AM stations usually covered from 10 to maybe 100
miles. At night they covered several thousand miles if ran at full
power so that is why they switched to a north/south directonal patern.

One of the larger towns had a transmitte that was 50,000 watts . I
think that is the most they could use and were called clear chanel
stations. There were only a small number of themin the US. I think that
at night they had to beam north and south.

Now many of the AM stations are off the air. Some had an AM and FM
transmitter and quit the AM and went totally to FM.

[Rob]

In Europe, broadcasting has traditionally been a state thing, and a
country had about 3 to 5 different programmes (even less early on)
that were transmitted by several transmitters in parallel to cover the
entire country. Depending on its size, that could be done with one or
two MW transmitter sites (as in a small country like the Netherlands)
or a larger number of sites. A single LW transmitter could cover a larger
country like France which is about the size of a smaller American state,
so that could be considered an alternative. Such transmitters typically
ran 500,000 watts, or even 2,000,000 watts as in the case of the LW
transmitter in Poland. But that covered all of Europe, some sources
say the entire world (but I think it is not likely that it covered all
of the world all of the time).

When FM was first deployed, it merely transmitted the same programmes
as the LW/MW transmitters but of course with many more sites to
achieve the required coverage. Once the deployment was complete and
the listeners widely got the required receiver equipment, the linking
was no longer done and the number of programmes doubled.

For a long time it was claimed that independent radio stations would
not fit in the rigid frequency allocation plans made across countries
to guarantee interference-free reception for everyone. Frequencies
were re-used only over very long distances. Conferences were held
every couple of years to adjust the allocations, and countries were
proud when they were able to score a new MW frequency or a number
of FM frequencies as required to deploy a new FM network for a single
programme.

Only much later this was all relaxed, and local and independent
stations were able to bid for frequencies. And now, all the stations
that were on MW have ceased transmitting there and have moved on to
DAB+ on VHF or sometimes to FM as well. And the plans to stop using FM
are on the horizon (some countries have already terminated FM broadcast).

[Ralph Mowery]

In article <slrnsg6286...@xs9.xs4all.nl>, nom...@example.com
says...

>
> In Europe, broadcasting has traditionally been a state thing, and a
> country had about 3 to 5 different programmes (even less early on)
> that were transmitted by several transmitters in parallel to cover the
> entire country. Depending on its size, that could be done with one or
> two MW transmitter sites (as in a small country like the Netherlands)
> or a larger number of sites. A single LW transmitter could cover a larger
> country like France which is about the size of a smaller American state,
> so that could be considered an alternative. Such transmitters typically
> ran 500,000 watts, or even 2,000,000 watts as in the case of the LW
> transmitter in Poland. But that covered all of Europe, some sources
> say the entire world (but I think it is not likely that it covered all
> of the world all of the time).
>
>

In the US just about anyone with the money could put up an AM or FM
radio station that wanted to. Provided there was radio spectrum space
for them to do it. All the government did was say yes or no to the
station and make sure they follow the rules as to the operation of the
sttion.
For the most part every station did their own programming. So as you
tune across the AM band you almost never heard the same thing on
different stations unless several were carring the same sports program.

I could see the probelm of Europe where there are many countries trying
to control the radio stations and Spectrum usage.

[Rob]

Ralph Mowery <rmow...@charter.net> wrote:
> In article <slrnsg6286...@xs9.xs4all.nl>, nom...@example.com
> says...
>>
>> In Europe, broadcasting has traditionally been a state thing, and a
>> country had about 3 to 5 different programmes (even less early on)
>> that were transmitted by several transmitters in parallel to cover the
>> entire country. Depending on its size, that could be done with one or
>> two MW transmitter sites (as in a small country like the Netherlands)
>> or a larger number of sites. A single LW transmitter could cover a larger
>> country like France which is about the size of a smaller American state,
>> so that could be considered an alternative. Such transmitters typically
>> ran 500,000 watts, or even 2,000,000 watts as in the case of the LW
>> transmitter in Poland. But that covered all of Europe, some sources
>> say the entire world (but I think it is not likely that it covered all
>> of the world all of the time).
>>
>>
>
> In the US just about anyone with the money could put up an AM or FM
> radio station that wanted to. Provided there was radio spectrum space
> for them to do it. All the government did was say yes or no to the
> station and make sure they follow the rules as to the operation of the
> sttion.

Yes, it was "the same" here. Anyone with the money could ask the government
for spectrum space. But the government always said NO. Not possible.
That brought some people with money to absolute despair, and lead
to pirate stations, e.g. on ships.
In procedures against those, it was always claimed that the frequency
they used was not available, because it was allocated to someone else.
Which of course it was, 1000 miles away.

> I could see the probelm of Europe where there are many countries trying
> to control the radio stations and Spectrum usage.

Yes, part of the problem was the many countries who all of course
wanted to have their say in the matter, all wanted to have frequencies
allocated, and all wanted to operate without interference.
And of course the fact that they were different countries and not
states of the same country made them less willing to compromise, and
the regulating body tended to over-regulate.

[Phil Allison]

Rob is Such a Tedious Wanker wrote:
================================

> >> But AM is too unspecific as a bandname because there
> >> indeed may be additional bands on short wave (SW) that also would
> >> be AM when on a car radio.
> >
> > ** " AM band " is a perfectly accurate name.
>>
> > The *only band* that is reserved for AM broadcasting.
>
>
> Maybe in the USA? Here we have/had at least two bands with AM broadcasting:
>
> LW 153-279 kHz
> MW 531-1602 kHz
>
> And then of course there are various SW bands, e.g. the 49M band.
>

** FFS asshole - learn to read.

What does " reserved " mean ????????

FYI

names mean what people mean when they use them.

Only dumb, ASD sufferers treat words as if they are math.


...... Phil

[Michael Trew]

I regularly listen to music via the internet or saved on my computer at
home. I have plenty of AM tuners; I really should get back into
listening to long distance AM at night.

[Michael Trew]

I'm sure the efficiency of those stations in that band would be the same
in the US as Europe; I find it interesting that they can still hang on
and be profitable (for the most part) over here.

How much more expensive is your electric? I pay $0.05/kWh -- although
electric is fairly cheap here. Parts of the US average roughly 3 times
that at about $0.15/kWh. Of course, that's just the "supply" portion;
there is a rate charged for "delivery" on our bills that changes with
the cost of supply. My current bill is $45.30 -- supply is 261 kWh @
$13.81 with "delivery" costing $31.49.

[Michael Trew]

I find these difference in broadcasting quite interesting, and I concur
with the majority of what Ralph has said about US radio.

Thank you for sharing!

[Rob]

Hey dumbfuck!
Maybe you can consider that:

- English is not my native language
- The world is not limited to the USA, the USA is only a small part of
the world. AND it is becoming more insignificant by the day.
- The statements I made about AM broadcasting are true.

[Rob]

Well, of course it is difficult to know what kWh prices a broadcasting
station pays, because they would have a different contract than a
consumer. It would not be the lowest possible rate, because likely
they want 24h/day service (unless they have a local generator they
can use on a daily basis). Large users that can switch off during
peak hours pay less per kWh.

As a consumer, I pay a kWh rate for supply and for delivery (separate),
plus a fixed rate for connection, and energy taxes over the whole thing.
Because energy taxes have a fixed basic allowance deducted after
calculating the percentage, it is difficult to give a total kWh price
because what I pay for my energy is different from what I pay for an
extra kWh on top. It is set up this way to encourage people to save
energy. What I pay over an entire year is about 0.09 euro/kWh but
the price for an extra kWh is more like 0.20 euro/kWh. A euro is
about $1.20 so it is like $0.11 and $0.24

But again, that is not what a customer with 1MW load would pay.

[Phil Allison]

Rob= Cunthead wrote:
==================

> >> > ** " AM band " is a perfectly accurate name.
> >>>
> >> > The *only band* that is reserved for AM broadcasting.
> >>
> >> Maybe in the USA? Here we have/had at least two bands with AM broadcasting:
> >>
> >> LW 153-279 kHz
> >> MW 531-1602 kHz
> >>
> >> And then of course there are various SW bands, e.g. the 49M band.

----------------------------------------------------------------------

> > ** FFS asshole - learn to read.
> >
> > What does " reserved " mean ????????
> >
> > FYI
> >
> > names mean what people mean when they use them.
> >
> > Only dumb, ASD sufferers treat words as if they are math.
> >
>

> Hey dumbfuck!

** Hey Shithead.

> Maybe you can consider that:
>
> - English is not my native language

** Wot - so you normally speak pigeon ???

"Reserved" is not in your dictionary ??

> - The world is not limited to the USA,

** FFS I'm Australian.

> - The statements I made about AM broadcasting are true.

** Truely FUCKING AWFUL BULLSHIT

Fuck YOU

.... Phil

[Rob]

Phil Allison <palli...@gmail.com> wrote:
> Rob= Cunthead wrote:
> ==================
>
>> >> > ** " AM band " is a perfectly accurate name.
>> >>>
>> >> > The *only band* that is reserved for AM broadcasting.
>> >>
>> >> Maybe in the USA? Here we have/had at least two bands with AM broadcasting:
>> >>
>> >> LW 153-279 kHz
>> >> MW 531-1602 kHz
>> >>
>> >> And then of course there are various SW bands, e.g. the 49M band.
> ----------------------------------------------------------------------
>> > ** FFS asshole - learn to read.
>> >
>> > What does " reserved " mean ????????
>> >
>> > FYI
>> >
>> > names mean what people mean when they use them.
>> >
>> > Only dumb, ASD sufferers treat words as if they are math.
>> >
>>
>> Hey dumbfuck!
>
> ** Hey Shithead.
>
>> Maybe you can consider that:
>>
>> - English is not my native language
>
> ** Wot - so you normally speak pigeon ???
>
> "Reserved" is not in your dictionary ??

I don't know the difference between "reserved for" and "allocated to"
in this context, which seems to upset you, but the bands I mentioned
are allocated to AM broadcast. So I presume they are reserved.
Apparently you see that differently, and express it loudly.

[Phil Allison]

Rob the ASD Lying Moron wrote:
=======================

>>
> >> Hey dumbfuck!
> >
> > ** Hey Shithead.
> >
> >> Maybe you can consider that:
> >>
> >> - English is not my native language
> >
> > ** Wot - so you normally speak pigeon ???
> >
> > "Reserved" is not in your dictionary ??
>

> I don't know the difference between ...

** Shit and chocolate.

> but the bands I mentioned
> are allocated to AM broadcast.

** You mentioned LOTS of bands.

So now you are trying to obfuscate my obviously true points with damn LIES !!!

> The statements I made about AM broadcasting are true.

** Truely FUCKING AWFUL BULLSHIT

Simple question for you :

Was it you father or you mother who taught you to be a damn LIAR??
Maybe a colossal *prick* like you doesn't know who his father was ?

Does you mother even know ?
Does she care?



..... Phil

[Rob]

I smile when I read this.
You were already in my killfile, I do not normally see your posts, but
when they are a reply to my posts they appear visible (pre-read) in my
thread display so I can still peek to see if something interesting is
there.

And I am amused by your drivel. It confirms my earlier decision to
killfile you, and that there is no need to worry that I would miss anything
of value written by you.

[Phil Allison]

Rob = some lying wog cunt :
======================

>
> I smile when I read this.

** You will NOT be smiling for much longer - asshole.

> You were already in my killfile,

** ROTFL - wot a blatant LIE.

> And I am amused by your drivel.

** Like hell you are.




..... Phil

[Tim R]

On Thursday, July 29, 2021 at 1:52:50 PM UTC-4, Ralph Mowery wrote:
> During the day the AM stations usually covered from 10 to maybe 100
> miles. At night they covered several thousand miles if ran at full
> power so that is why they switched to a north/south directonal patern.
>
> One of the larger towns had a transmitte that was 50,000 watts . I
> think that is the most they could use and were called clear chanel
> stations. There were only a small number of themin the US. I think that
> at night they had to beam north and south.

My memory is that they had to cut power to 10% at night.

[Michael Trew]

Fair enough, thanks!

[legg]

On Wed, 28 Jul 2021 19:15:04 -0700 (PDT), Phil Allison
<palli...@gmail.com> wrote:

>legg wrote:
>--------------
>>
>> > Guess having no ugly antenna sells cars to those who value cosmetics above results.
>> > No wonder the are many "after market" alternatives available.
>> >
>> >
>> >..... Phil
>> >
>> I believe it was an anti-vandalism thing.
>>
>
>** Automatic, powered antennas did that perfectly.
> For a fraction of the cost.

Hokey.

Imbeded antennas introduced minimal added cost and had zero
moving parts.

RL

[Peter W.]

>
> Imbeded antennas introduced minimal added cost and had zero
> moving parts.

And here, in the 'Great, Salty, Frozen North', power antennas had a typical service life of about 3 years, at best. No big deal for the car flippers, but for those of us who keep cars well into their second centennial (in thousands), or longer, an issue.

Keep in mind that (at least) here in the US, all windshields are laminated, some even have three (3) layers. Many have embedded sensor shields and sun shields , as well as various degrees of tinting. Adding an antenna or even antennas has a tiny incremental cost to all that. Our Volvo XC70 had an antenna on the perimeter of the windshield - in the glue-zone, one on the driver (left) side rear window, and one on the rear window (tailgate). No shark-fin, but as a 2005, Navigation was not as prevalent then as now. The system consists of a radio with integrated CD changer and Dolby Pro Logic1 processor that runs a powerful, 300 Watt amplifier, which in turn runs 11 (V70, V70 R, XC70), 13 (S60 S60 R) or 9 (S80) speakers (from the brochure).

The antenna on the rear passenger window, I am told, was a passive radiator for cell phones. Never took the time to check that.

Peter Wieck
Melrose Park, PA

[Phil Allison]

legg wrote:

=============

>> >
> >> I believe it was an anti-vandalism thing.
> >>
> >
> >** Automatic, powered antennas did that perfectly.
> > For a fraction of the cost.
>
> Hokey.
>
> Imbeded antennas introduced minimal added cost and had zero
> moving parts.
>

** Not even faintly plausible.


..... Phil

[Jeroni Paul]

Rob wrote:
> But I have a French car and in France there are
> several LW transmitters (or at least, there were). They tend to have
> a longer range and are less affected by propagation changes. And of
> course they often use ridiculous amounts of power and large antennas.
>

> But it has long been discontinued. Too costly, and replaced by Internet.

The France LW station at 162kHz did broadcast the programs of France Inter radio AND the current time encoded in its carrier for radio controlled clocks. I always tought that was an efficient use of resources. That was until 2016 when they stopped transmitting the radio but kept transmitting the time and still do.
https://www.youtube.com/watch?v=Q3D8XBOXjts

Since they keep the transmitter operating I think they could broadcast a radio, now is just a wasted resource. I guess it probably comes down to the radio not willing to pay for that transmission, still they could offer some public service.

I have a car radio with LW and autotunning and it stops at 162, but only background noise comes out. It does a good job of autotunning LW and MW, hardly ever stops on useless noises.

[Rob]

Yes that was a clever system. But it also shows an unfortunate depedency...

However, the power was originally 2,000,000 Watts and it has since been
reduced to 800,000 Watts and of course the mains power consumption has
been reduced even more because of course the strong AM modulation is no
longer present (the time is transmitted in PSK).

Presumably the new power level has been determined "experimentally" to
have a reliable clock synchronization for existing clocks on the system,
however the German time transmitter DCF-77 operates with only 50kW
on 77.5 kHz so one would think that a comparable power level would
be sufficient for 162 kHz as well. But of course the exising installs
may have gotten accustomed to the earlier level and the operator may
be forced to maintain a relatively high power.

The British LW transmitter Droitwich was originally on 200 kHz and its
frequency was also very accurate and was sometimes used as a reference
frequency e.g. to calibrate equipment or to stabilize oscillators.
At the time of the shift to the 9 kHz raster it moved to 198 kHz which
was of course inconvenient for those users. However it is still as
stable as before. I have seen mod circuits at that time that e.g.
used a PLL to lock a 200 kHz oscillator to the 198 kHz carrier using
a divide-by-100 and a mixer to do 200-2 => 198 kHz and lock to that.

At this time they also transmit data in PSK, I don't think that was the
case in those early days (I'm not sure). This is probably the reason
it is still on air, normally such a station would have been shut down
by now but such extra features may make systems dependent on it.
(most other MW stations in the UK have been shut down by now)

[Ralph Mowery]

In article <slrnsga61p...@xs9.xs4all.nl>, nom...@example.com
says...

>
> The British LW transmitter Droitwich was originally on 200 kHz and its
> frequency was also very accurate and was sometimes used as a reference
> frequency e.g. to calibrate equipment or to stabilize oscillators.
> At the time of the shift to the 9 kHz raster it moved to 198 kHz which
> was of course inconvenient for those users. However it is still as
> stable as before. I have seen mod circuits at that time that e.g.
> used a PLL to lock a 200 kHz oscillator to the 198 kHz carrier using
> a divide-by-100 and a mixer to do 200-2 => 198 kHz and lock to that.
>
>

I think it is still being done due to the older equipment as to using
some very low frequencies ( below 500 kHz) to calibrate frequencys and
clocks.

With the GPS systems I would think that they would be used by most
everything now and probably more accurate. I use them to calibrate my
radio service monitors for frequency. I can buy a $ 20 receiver board
and hook it to my oscilloscope and service monitor and set it to better
accurecy than the normal drift of the monitor after a week .

I don't know what the signal would be like in other parts of the world,
but the US puts out standard frequency and time sgnals on 2.5, 5,10, 15,
maybe 20 MHz. There are a couple of frequencies in Canada around 7.3
and 14 something MHz for time.
Most cell phones are probably accurate to a second or so.

[Brian Gregory]

On 28/07/2021 05:05, Phil Allison wrote:
> Brian Gregory wrote:
> ===============
>
>> Phil Allison wrote:
>>
>>> you may have noticed that few modern cars have any visible AM/FM antennas these days.
>>> Many have a "shark fin" antenna on the roof for GPS and possibly 4G cell phones - frequencies used are similar.
>>> Others have a short whip antenna somewhere, not much good for AM.
>>
>> I don't think a loop aerial on a car window would work at all well
>> surrounded by the much bigger thinker more conductive loop consisting of
>> the metal body of the vehicle in which the window is fitted.
>
> ** Not true.
> AM loops sense the magnetic field of the incoming EM wave.
> Some are made from co-ax with the outer shield grounded to eliminate the E field.
> Less static noise that way.
> The nearby car bodywork has little effect on a window loop.

It wouldn't be just nearby or just shielding it would form a shorted turn.

With shielded loops the shield is not connected all round to form a
shorted turn.

If you can't see that you're not qualified to discuss this at all.

--
Brian Gregory (in England).

[Brian Gregory]

On 28/07/2021 07:58, Jeff Layman wrote:
> Perhaps that's the difference between the USA and Europe. I can't
> remember seeing a car radio with MW here in the UK in at least the last
> 10 years - probably more like 20. Anyway, I miss the standard repair
> sometimes seen here many years ago for telescopic antennas - a
> "reshaped" wire coat hanger!

Yes I had forgotten I had ventured out of the uk.* newsgroups in to
international territory. :/

[Brian Gregory]

On 29/07/2021 12:35, Rob wrote:
> Energy is expensive here and a typical radio station cannot pay the 100kW-1MW
> power consumption of an AM transmitter.

AM transmitters with over 50kW output are not used in the US at all.
(There were a handful of experimental ones at one stage in the past)

Yes in Europe higher powers were not uncommon, a few were as high as 1MW.

[Brian Gregory]

On 29/07/2021 05:18, Phil Allison wrote:
> Rob wrote:
>> FM *is* used as a band name here, although of course it formally is
>> just as wrong as AM.
>
> ** Wot drivel.
>
> Again, it is the only band reserved for high quality FM broadcasting.

But it's not called "high quality FM broadcasting", it's just called "FM".

What about all the other frequencies where narrow band FM is used for
walkie-talkies, remote controls etc. etc.?

[Brian Gregory]

On 30/07/2021 03:14, Phil Allison wrote:
> Only dumb, ASD sufferers treat words as if they are math.

How insulting to people with ASD.

[Rob]

Well as you say, with GPS it is not really relevant anymore.
The LW transmitters may be very stable but the propagation adds jitter
and the interference from local equipment is troublesome as well.

It is easiest today to get a GPSDO that outputs 10 MHz as a reference
for your service equipment, there are devices in different price and
performance levels.

I do have a Leo Bodnar GPS locked oscillator that I can program to
output any frequency and sometimes use to calibrate receivers etc.
Very cheap.
(it does not only use NAVSTAR but also GLONASS and GALILEO)

[Rob]

As I explained in another followup, it seems related to the situation that
in Europe radio stations traditionally were a state thing, and you
would have to cover an entire country with the same signal, so high
output power is a reasonable move. In the USA, it looks like it always
was a commercial thing and more focused on local operation, servicing
a single town and surrounding area.

Still, with 50kW transmitter output AM a typical station would rather
place 5 FM transmitters of 5kW and have the same coverage area but
with much better quality. For a 5kW AM transmitter a single FM site
would probably do it.
(FM transmitters usually have antennas with ~ 10dB of gain so they
effectively transmit 10 times more than their rated output power, which
cannot reasonably done with MW (AM) transmitters due to physical limitations)

[Phil Allison]

Brian Gregory wrote:
===============

Phil Allison wrote:
> > Rob wrote:
> >> FM *is* used as a band name here, although of course it formally is
> >> just as wrong as AM.
> >
> > ** Wot drivel.
> >
> > Again, it is the only band reserved for high quality FM broadcasting.
>
> But it's not called "high quality FM broadcasting", it's just called "FM".

** It called " The FM band " and it IS reserved for "wide band" FM broadcasting.

The name refers to what exists.

> What about all the other frequencies where narrow band FM is used for
> walkie-talkies, remote controls etc. etc.?

** Yawnnnnnnnnn.....


.... Phil

[Phil Allison]

Brian Gregory wrote:
=================

> Phil Allison wrote:
>
> > Only dumb, ASD sufferers treat words as if they are math.
>
> How insulting to people with ASD.

** ROTFL !!!!!!

Obviously YOU are one of them.

Folk with ASD make all those around them suffer by shoving their bizarre thinking down their throats.

Plus totally misconstruing everyday words and their meanings.

..... Phil

[Phil Allison]

Brian Gregory wrote more dumb bullshit:
================================

> >>
> >> I don't think a loop aerial on a car window would work at all well
> >> surrounded by the much bigger thinker more conductive loop consisting of
> >> the metal body of the vehicle in which the window is fitted.
> >
> > ** Not true.
>
> > AM loops sense the magnetic field of the incoming EM wave.
> > Some are made from co-ax with the outer shield grounded to eliminate the E field.
> > Less static noise that way.
> > The nearby car bodywork has little effect on a window loop.
>
> It wouldn't be just nearby or just shielding it would form a shorted turn.

** Nonsense.

The bodywork in discontinuous and not well coupled to the antenna.
Millions of cars use the idea and it fucking works.

> With shielded loops the shield is not connected all round to form a
> shorted turn.

** Never said it was.



..... Phil

[Brian Gregory]

Oh, I forgot.

In the US there are narrow band FM weather broadcasts.

NOAA weather I think it's called.

Definitely FM (albeit narrow band FM).

Definitely not in the 87.5-108 MHz band (somewhere around 162MHz IIRC).

[Phil Allison]

Brian Gregory = Rabid ASD fueled Lunatic wrote:
=====================================

>>
> >>> FM *is* used as a band name here, although of course it formally is
> >>> just as wrong as AM.
> >>
> >> ** Wot drivel.
> >>
> >> Again, it is the only band reserved for high quality FM broadcasting.
> >
> > But it's not called "high quality FM broadcasting", it's just called "FM".
> >
> > What about all the other frequencies where narrow band FM is used for
> > walkie-talkies, remote controls etc. etc.?
> >
> Oh, I forgot.
>
> In the US there are narrow band FM weather broadcasts.
> NOAA weather I think it's called.
> Definitely FM (albeit narrow band FM).
> > Definitely not in the 87.5-108 MHz band (somewhere around 162MHz IIRC).
>

** Like dog with a bone, this blithering IDIOT will just not let go of his bonkers notion.

Likely he believes the name "Steak Sauce" is false too.

Got no damn steak in it......


..... Phil

[David Lesher]

Brian Gregory <void-invalid...@email.invalid> writes:


>But most cars nowadays only have FM and DAB+ anyway.

For some reason, Tesla's do not have an AM band.
I can't imagine why that is...

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

[David Lesher]

Brian Gregory <void-invalid...@email.invalid> writes:


>AM transmitters with over 50kW output are not used in the US at all.

cough, cough....

WLW. It ran 500KW+ in the past, but regulators cut them back to
the ordinary 50KW level in ~1940.

The transmitter tubes had 3-phase filiments, if that gives you
some idea of their size.

There were multiple stories of farmers getting bit by their hot
barbed wire fences, metal roofs that played WLW, etc.

[Rob]

David Lesher <wb8...@panix.com> wrote:
> Brian Gregory <void-invalid...@email.invalid> writes:
>
>
>>But most cars nowadays only have FM and DAB+ anyway.
>
> For some reason, Tesla's do not have an AM band.
> I can't imagine why that is...

You can't? Well I can!
- not useful in large parts of the world
- interference from motor control

[Rob]

David Lesher <wb8...@panix.com> wrote:
> Brian Gregory <void-invalid...@email.invalid> writes:
>
>
>>AM transmitters with over 50kW output are not used in the US at all.
>
> cough, cough....
>
> WLW. It ran 500KW+ in the past, but regulators cut them back to
> the ordinary 50KW level in ~1940.
>
> The transmitter tubes had 3-phase filiments, if that gives you
> some idea of their size.

Actually it makes no sense to make an AM (MW) transmitter using tubes
today. Designs using semiconductors and some switching mode are
3+ times more efficient (mains->antenna) and that is a big difference
at those powerlevels.

See e.g. Nautel NX https://www.nautel.com/products/am-transmitters/nx-series/

[Ralph Mowery]

In article <slrnsistli...@xs9.xs4all.nl>, nom...@example.com
says...

>
> You can't? Well I can!
> - not useful in large parts of the world
> - interference from motor control
>
>

Probably the interference from the other electronics in the car. Easy
to eliminate if you just leave the receiver out of the radio.

I just hope it is not like a friend that had a car about 40 years ago
where he replaced the spark plug wires and spark plugs with the non
resistor types. If you had an outside TV antenna which almost everyone
did back then you could tell he was on the way from about 3 blocks away
and when he got in the driveway you lost all of the TV station.

[Phil Allison]

Rob the Imbecile wrote:
==================

> >
> > For some reason, Tesla's do not have an AM band.
> > I can't imagine why that is...
>
> You can't? Well I can!
> - not useful in large parts of the world

** Choke, choke ???
WTF is this idiot on ?

> - interference from motor control

** Obvious reason.
AM radio simply does not work satisfactorily in their wacky contraptions.


..... Phil

[Michael Terrell]

There was one 500KW AM station, WLW. It was on 700KHz and it operated under an experimental license, and it was shut down in 1939. I saw the site 30 years later, along with the Bethany Ohio VOA site.

http://j-hawkins.com/wlw.shtml

Modern AM broadcast transmitters are a lot more efficient. All solid state, and no separate modulator which operates like a digital audio amplifier. It is built of plug in RF trays that can be hot swapped without shutting down the transmitter. The built in computer monitors the operation of each tray, and lets the staff know that a tray has failed, or can email the engineer if he is off site. Harris Broadcast introduced the first generation in the late '80s. Harris used to have white papers on their website. You might find them on the 'Wayback Machine' if you want more details.

[David Lesher]

Rob <nom...@example.com> writes:

>David Lesher <wb8...@panix.com> wrote:
>> Brian Gregory <void-invalid...@email.invalid> writes:
>>
>>
>>>But most cars nowadays only have FM and DAB+ anyway.
>>
>> For some reason, Tesla's do not have an AM band.
>> I can't imagine why that is...

>You can't? Well I can!

<https://www.merriam-webster.com/dictionary/satire>

[David Lesher]

Rob <nom...@example.com> writes:

>> WLW. It ran 500KW+ in the past, but regulators cut them back to
>> the ordinary 50KW level in ~1940.
>>
>> The transmitter tubes had 3-phase filiments, if that gives you
>> some idea of their size.

>Actually it makes no sense to make an AM (MW) transmitter using tubes
>today. Designs using semiconductors and some switching mode are

^^^^^

>3+ times more efficient (mains->antenna) and that is a big difference
>at those powerlevels.

The transistor had not been invented when WLW's transmitter was built.
It was decades later before high power FET's appeared.
<https://youtu.be/CbHjcwIoTiY>

[David Lesher]

Ralph Mowery <rmow...@charter.net> writes:

>> - interference from motor control

>Probably the interference from the other electronics in the car. Easy
>to eliminate if you just leave the receiver out of the radio.

I assume you are pulling his leg. Think of the power levels involved
in the drive motor electronics.

(You might research what FCC regulations cover electric car RFI.
You can be sure Musk did...)

[Rob]

David Lesher <wb8...@panix.com> wrote:
> Ralph Mowery <rmow...@charter.net> writes:
>
>>> - interference from motor control
>
>>Probably the interference from the other electronics in the car. Easy
>>to eliminate if you just leave the receiver out of the radio.
>
> I assume you are pulling his leg. Think of the power levels involved
> in the drive motor electronics.
>
> (You might research what FCC regulations cover electric car RFI.
> You can be sure Musk did...)

I would not at all be surprised when FCC regulations covering RFI
specify maximum levels that are still way too high to allow reception
of AM radio in the car itself.

[Ralph Mowery]

In article <sgo3nb$j7o$2...@reader1.panix.com>, wb8...@panix.com says...

>
> >Probably the interference from the other electronics in the car. Easy
> >to eliminate if you just leave the receiver out of the radio.
>
> I assume you are pulling his leg. Think of the power levels involved
> in the drive motor electronics.
>
> (You might research what FCC regulations cover electric car RFI.
> You can be sure Musk did...)
> --
>
>

No, not pulling a leg, just guessing.

Many devices will interfere with AM radios. The FCC has a limit on how
much is allowed. The car may just produce enough to affect the onboard
AM radio, but not ones 50 feet away.

People buying the electric cars probably do not listen to the AM
stations anyway,but FM and the Sirus radio.

[Peter W.]

> I would not at all be surprised when FCC regulations covering RFI
> specify maximum levels that are still way too high to allow reception
> of AM radio in the car itself.

Think it through: A vehicle is a rolling Faraday cage. Even the glass will be from about 0.2% to 0.8% iron, providing some shielding (and why many automobiles have passive cell-phone 'repeaters' for lack of a better word - antenna designed to take cell rF to outside the vehicle - both our Ford C-Max & our Subaru Forester are so-equipped). This suggests that a well-designed & shielded AM front-end and an external antenna should do the trick nicely. Yeah-but.

That would make that AM front-end no longer a trivial 'extra chip' in an already trivial device. And put at least one more step in the glass manufacturing process. Not gonna happen. Note that it is not just the Tesla that has dropped AM - several other all-electric vehicles have done the same. Funny thing, however. The C-Max with a (depending on conditions) 15-35 all-electric range does fine in AM.

Peter Wieck
Melrose Park, PA

[Rob]

Ralph Mowery <rmow...@charter.net> wrote:
> In article <sgo3nb$j7o$2...@reader1.panix.com>, wb8...@panix.com says...
>>
>> >Probably the interference from the other electronics in the car. Easy
>> >to eliminate if you just leave the receiver out of the radio.
>>
>> I assume you are pulling his leg. Think of the power levels involved
>> in the drive motor electronics.
>>
>> (You might research what FCC regulations cover electric car RFI.
>> You can be sure Musk did...)
>> --
>>
>>
>
> No, not pulling a leg, just guessing.
>
> Many devices will interfere with AM radios. The FCC has a limit on how
> much is allowed. The car may just produce enough to affect the onboard
> AM radio, but not ones 50 feet away.

That is what I mean. To know the difference between RFI regulations
and reasonable AM reception, just ask any radio amateur (as the previous
poster probably is). The common levels of interference these days,
likely emitted by fully compliant devices, overwhelm all but the
strongest signals on frequencies below a couple of MHz.

[Ralph Mowery]

In article <slrnsiv9t9...@xs9.xs4all.nl>, nom...@example.com
says...

>
> That is what I mean. To know the difference between RFI regulations
> and reasonable AM reception, just ask any radio amateur (as the previous
> poster probably is). The common levels of interference these days,
> likely emitted by fully compliant devices, overwhelm all but the
> strongest signals on frequencies below a couple of MHz.
>
>

I am aproching 50 years an a radio amateur. It is not just a couple of
MHz but even higher. Riding around with a transceiver around 52 MHz and
some of the fuel pumps and even the stop lights create some noise
problems. Even some of the lights in homes will cause radio problems.

The FCC allows a certain amount of unwanted radiation by almost any
electrical device . I have not kept up with things like that in a long
time. When the personal computers came out there were some programs
written where you could sit a radio near the computer and use the
computer to make music with. The FCC came out with two sets of
rulings. One for home devices which were stricter than the computers
used for industries.

[David Lesher]

Ralph Mowery <rmow...@charter.net> writes:


>Many devices will interfere with AM radios. The FCC has a limit on how
>much is allowed. The car may just produce enough to affect the onboard
>AM radio, but not ones 50 feet away.

The FCC regulates emitters/emissions by category. The fun part
is which one does a car fall under?

[Michael Trew]

On 8/31/2021 12:48 PM, David Lesher wrote:
> Brian Gregory<void-invalid...@email.invalid> writes:
>
>
>> But most cars nowadays only have FM and DAB+ anyway.
>
> For some reason, Tesla's do not have an AM band.
> I can't imagine why that is...
>

I rented a new, '20 or '21 Uhaul (GMC Sierra) pickup truck for a day.
The AM radio is actually incredible; sounds better than it does in any
of my 20+ year old cars. I was very impressed, it seemed that it
filtered out lots of static. Distant stations had minimal static
interference, just the audio went in and out slowly as the station got
weaker.

[Phil Allison]

Ralph Mowery wrote:
==================

>
> People buying the electric cars probably do not listen to the AM
> stations anyway,but FM and the Sirus radio.

** AM radio has a huge advantage at long distance from the Tx.

But seeing as Teslas cannot do long trips into the countryside.....


...... Phil

[Michael Terrell]

On Wednesday, September 1, 2021 at 12:54:19 PM UTC-4, Ralph Mowery wrote:
> In article <slrnsiv9t9...@xs9.xs4all.nl>, nom...@example.com
> says...
> >
> > That is what I mean. To know the difference between RFI regulations
> > and reasonable AM reception, just ask any radio amateur (as the previous
> > poster probably is). The common levels of interference these days,
> > likely emitted by fully compliant devices, overwhelm all but the
> > strongest signals on frequencies below a couple of MHz.
> >
> >
> I am aproching 50 years an a radio amateur. It is not just a couple of
> MHz but even higher. Riding around with a transceiver around 52 MHz and
> some of the fuel pumps and even the stop lights create some noise
> problems. Even some of the lights in homes will cause radio problems.

There are some traffic lights around here that you can hear change colors from almost a mile away. The noise is coupled into the power lines feeding a substation, and it is re radiated from them. Basically a carrier current noise source from a poorly filtered SMPS. The high failure rate of the LED lamps in the traffic lights has more being switched back to lower efficiency, extra long life incandescent bulbs. Just about every LED light you see has one or more clusters of dead LEDs, in spite of some people's claim that they do not fail..