Radio conversion
Gene
While in England in `91, I picked up a Ford motor car radio receiver.
P21 79GB-18K810 HA . Two band , LW & MW .. (166 KHz - 285 KHz LW
& 666KHz - 1500Khz MW +/- ) .I would like to extend the LW band as
high in frequency as i can , and the MW band as low as i can in
frequency..I.F. is 465 kHz...Object : To create a beacon ( 200KHz -
400 KHz ) receiver...
Is there anyone out there that has any experience , and or ideas with
what i have in mind ?
TIA Gene WB7NGI
Tim Shoppa
If analog tuning then you add or remove capacitance to each LC and
hope that the padding can be adjusted or supplemented enough so that
everything (mixer and front end) tracks. It won't be so much
"extending" the tuning range but instead will be "shifting" the tuning
range.
If digital tuning then you'll have to locate the schematic for the PLL
chipset and see if you can convince the local oscillator to shift far
enough. With some PLL chipsets there are programming pins or diodes
that set the allowed range. In many cases, if you don't need the
original tuning range, you can patch in a divide by two or just change
the reference oscillator. If you change the reference oscillator then
the display won't be right but will be mathematically related to the
actual frequency.
I collect British tabletop radios and am quite familiar with their
longwave dial on tube-type analog sets (my favorite is when they do
not list frequencies but only wavelengths) but am not particularly
familiar with British car radios. My one piece of advice with respect
to car radios from foreign autos of 70's vintage or older, is to check
carefully WRT 6V or 12V and WRT to negative ground or positive ground.
Tim N3QE
Gene
Tim, thanks for the reply...analog...made in Canada....so i assume it
is a Philco-Ford , unable to find schematic , will have to do some
reverse engineering to to figure out what cap , is what
Thanks , Gene WB7NGI
Tim Shoppa
> Tim, thanks for the reply...analog...made in Canada....so i assume it
> is a Philco-Ford , unable to find schematic , will have to do some
> reverse engineering to to figure out what cap , is what
Internally most of the good AM car radios I've met had mechanically
ganged slug tuning, although variable capacitor tuning existed too.
That's great if you're comfortable adjusting the mechanics of the
radio internally to get the tracking right. Remember, you won't be
broadening the tuning range, you'll be shifting the tuning range.
Tim N3QE
Bill M
� guess by about 1990 (20 years ago) they had all abandoned the
slug-tuned stages.
I had a '90 era car radio found in the Caribbean. It locked onto the
9kc European channels. I'm sure there was some chip jumpering that
would allow tuning to American 10kc channels but I never could find the
info.
joeturn
> On Dec 29, 8:38 pm, Gene <mog...@aol.com> wrote:
>
> > Tim, thanks for the reply...analog...made in Canada....so i assume it
> > is a Philco-Ford , unable to find schematic , will have to do some
> > reverse engineering to to figure out what cap , is what
>
> Internally most of the good AM car radios I've met had mechanically
> ganged slug tuning, although variable capacitor tuning existed too.
I once broadened the band of a Titan 4 reciever by
adding a varible capacitor with a spst it might need another varible
capacitor with a spdt to get the other end of the spectrum.
raypsi
The only way to make that work is with a converter.
Back in the day before police scanners, I made a converter that
converted the 70cm police band down to the AM broadcast band. 530Khz
thru 1600Khz was the band back then. My converter could put 3 local
police frequencies on the AM band.
All the converter is is an LO, input tank circuit, and a mixer. The
only active component was the LO. I used a CB rock which were dirt
cheap. Caught the 70cm harmonic into the mixer, getting the police
band down to the AM band.
I made a version that plugged inline with the car antenna and the car
radio, that could be switched in and out.
I couldn't make enough of them, Was the best selling product I ever
made.
73 OM
de n8zu
joeturn
>
> - Show quoted text -
Raypsi
You cant find the specs on a converter anymore!
I probably used one of your gadgits back in the 70s, the car am radio
was converted to cb band!
My titan 4 reciever had a trimmer just above the vfo to zero its
frequency with the dial reading!
I simply put the trimmers center point to a toggle switch that led to
two other varible capacitors and could go up or below the cb band,
tuning each to a specified value!
I would love to be able to get a converter to fill in the gaps on a
ubc 780 xlt.
A converter to allow it to start at 100 hz and go to 4 gigs will be
your next best seller without having to use the pc software;)
Scott
How did that work? Wasn't the police band using FM back then like they
do today? I suppose the RF signal may have had enough "AM" component
perhaps?
Ralph Mowery
"Scott" <acepilo...@bloomer.net> wrote in message
news:s-6dnSjcKZyZ4NvW...@bright.net...
> raypsi wrote:
>> Hey OM:
>>
>> The only way to make that work is with a converter.
>> Back in the day before police scanners, I made a converter that
>> converted the 70cm police band down to the AM broadcast band. 530Khz
>> thru 1600Khz was the band back then. My converter could put 3 local
>> police frequencies on the AM band.
>> All the converter is is an LO, input tank circuit, and a mixer. The
>> only active component was the LO. I used a CB rock which were dirt
>> cheap. Caught the 70cm harmonic into the mixer, getting the police
>> band down to the AM band.
>>
>
> How did that work? Wasn't the police band using FM back then like they do
> today? I suppose the RF signal may have had enough "AM" component
> perhaps?
>
It is easy to detect FM on an AM radio by using slope detection. Not the
best way, but it works.
highlandham
> http://www.tpub.com/neets/book12/51c.htm
==========================================
Tnx for the above excellent (wide-ranging) reference.
Frank GM0CSZ / KN6WH
raypsi
Yeah, a converter to gets the blocked cell phone bands. They making
those things in some ones garrage in Hong Kong.
Naw the top selling device would be a cell phone jammer. Flick it on
and all the cell phones within a certain radius go down.
A jammer would be highly illegal though, even a police converter
nowadays would be the same: illegal.
73 OM
de n8zu
> your next best seller without having to use the pc software;)- Hide quoted text -
joeturn
>
> - Show quoted text -
No the police bands are wide open they dont use digital because of the
range. They all still use analog because of its dependability!
They do use cell phones to communicate privately on digital,but theirs
still that problem of 40 kz between transmit and recieve to over come.
That only got you a dependent pimp or drug dealer.The cordless phones
are still of interest however,the scanners that can get into the
2-4gigs are too expensive for the ordinary joe<I;-)
joeturn
The authorities/military are the only ones that have a need to jam RF
(a cell phone) but those are all ready furnished them!
highlandham
> range. They all still use analog because of its dependability!
>
> They do use cell phones to communicate privately on digital,but theirs
> still that problem of 40 kz between transmit and recieve to over come.
>
> That only got you a dependent pimp or drug dealer.The cordless phones
> are still of interest however,the scanners that can get into the
> 2-4gigs are too expensive for the ordinary joe<I;-)
In Britain the police is now on a digital nation wide trunking system
,originally called Tetra ; I believe it is a Motorola system .
The Ambulance- and other public services are gradually also adopting the
system ,which eventually will be pan-european .
99% of all the cordless phones are now digital (mostly 900MHz)
Many are of the DECT type (Digitally Enhanced Communication Technology)
Those cordless phones which are GAP compatible (even when from different
manufacturers) can be used with the same base station (unit wired to
the telephone system)
Frank GM0CSZ / KN6WH
Geoffrey S. Mendelson
> 99% of all the cordless phones are now digital (mostly 900MHz)
> Many are of the DECT type (Digitally Enhanced Communication Technology)
> Those cordless phones which are GAP compatible (even when from different
> manufacturers) can be used with the same base station (unit wired to
> the telephone system)
Maybe in the US they are. In the rest of the world, and many sold in the US,
use the 1.8gHz band. The low end of the US 1.9gHz band overlaps the high
end of the 1.8gHz band used elsewhere, so they can be 1.8 gHz here and
1.9 gHz there. :-)
There are some 2.4gHz cordless phones, but AFAIK they are slowly being phased
out because the poorly designed ones interfere with WiFi, and the good ones
that look for a clear channel can't function in a heavy WiFi environment.
5.8gHz phones, only legal in the Americas, are similar to their 2.4 gHz cousins
and eventually as the 5.8gHz gets taken over by 802.11n networks, they too
will disapear.
BTW, GAP phones are not always useable with other base stations. In order
to access a base station a handset must register with it, and currently that
has to be done by placing both the handset and base station in registration
mode and inserting the handset into the base station. Works in theory, but
every manufacturer uses a different base design and they contacts won't mate.
Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel g...@mendelson.com N3OWJ/4X1GM
New word I coined 12/13/09, "Sub-Wikipedia" adj, describing knowledge or
understanding, as in he has a sub-wikipedia understanding of the situation.
i.e possessing less facts or information than can be found in the Wikipedia.
joeturn
reach the nearest microwave tower then then the signal is relayed!
This is most likely the way the Europeans use digital as it's no good
over a distance of 30 miles without being relayed.
The only bennifit of digital is a weak signal demanding cable or
satellite subscriptions$$$$
To amplifi the digital signal enough to be usable at greater distances
will have a domino effect on its technology of being deadly due to
exposure to microwaves to the human brain and redering one impotent!
http://www.articlesbase.com/technology-articles/the-harmful-effects-of-cell-phone-use-413085.html
This release of harmful cellphone use will hurt the industry or do
away with it completely!!
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
joeturn
harmful but conviniently the results were altered!
Here's a better read for cellphone's harmful effects!
http://www.infowars.com/cell-phone-use-harmful-to-unborn/
but mega biz has no feelings where loss of revenue is concerned, they
just lobby in what ever brings the biggest bux<I;-)
Rob
> BTW, GAP phones are not always useable with other base stations. In order
> to access a base station a handset must register with it, and currently that
> has to be done by placing both the handset and base station in registration
> mode and inserting the handset into the base station. Works in theory, but
> every manufacturer uses a different base design and they contacts won't mate.
There is no "inserting in the base station" during registration of a
handset with a base station. You only select some function, key-in some
number, and press some button.
My base station does not even have the facility to charge a handset,
there is a separate charger base for that.
Rob
> In Britain the police is now on a digital nation wide trunking system
> ,originally called Tetra ; I believe it is a Motorola system .
> The Ambulance- and other public services are gradually also adopting the
> system ,which eventually will be pan-european .
In the Netherlands it has been active for several years already.
There is no more police radio snooping using FM scanners anymore.
(of course this means the public cannot serve as an extra eye and ear
to the police anymore, either)
highlandham
> Geoffrey S. Mendelson <g...@cable.mendelson.com> wrote:
>> BTW, GAP phones are not always useable with other base stations. In order
>> to access a base station a handset must register with it, and currently that
>> has to be done by placing both the handset and base station in registration
>> mode and inserting the handset into the base station. Works in theory, but
>> every manufacturer uses a different base design and they contacts won't mate.
> There is no "inserting in the base station" during registration of a
> handset with a base station. You only select some function, key-in some
> number, and press some button.
> My base station does not even have the facility to charge a handset,
> there is a separate charger base for that.
That's correct. My Philips system does not need inserting ,it is like
Rob describes . Any GAP compatible DECT phone can be registered (up to a
certain maximum number per base station)
I have checked the range (max distance between base station and any
handset) . In open country (no buildings or other line of sight
obstructions other than 1 building wall) the range is not less than 100
metres.
Frank GM0CSZ / KN6WH
terry
Based on the OP. Postulating some numbers!
The Long Wave band 166 to 285. That's ratio of 1:1.7
The local oscillator with an IF of 465 would be (465 + 166 = 631) to
(465 + 285 = 750) a ratio of only 1:1.18!
The Medium Wave band 666 to 1500. A ratio of 1:2.25
The local oscillator being (465 + 666 = 1131) to (465 + 1500 = 1965) a
ratio of 1:1.73.
To tune 200 to 400 khz. is a ratio of (at least) 1:2. And retaining
an IF of 465 would require, say, a local oscillator variation from
(465 + 200 = 665) to (465 + 400 = 865) a ratio of 865/665 or 1:1.3
However those 200 to 400 kilohertz aircraft beacon radios, covering
specifically 200 to 400 are quite often on eBay!
Another alternative would be a 190 to 550 kilo hertz ARC-5/BC453
'Command radio'. Those have 12 volt tubes that can easily be rewired
from 24 to 12 volt operation.
Another quicker alternative would be some form of small solid state
converter tuned or fixed into the Med. Wave band.