Yagi antenna for FM/AIR reception

[Jim]

I know this is amateur group but I thought you guys will have some answer.
Got a unused TV yagi antenna with about 12 directors, dipole, and a reflector.
Want to hook up a 300 ohm cable to my Sony 2010 receiver FM input. Do I need to
hook up a balun? If yes, would a 75 ohm be good enough? OR should I just forget
about this plan? TIA.

[Tom Ring]

Depending on the antenna it will work well or not so well, but still may
cover VHF aircraft. A 300 to 75 balun should be fine, assuming the
antenna uses a 300 ohm balanced feed.

And aircraft antennas tend to be vertical, at least the ones on the
ground, so orient it that way.

tom
K0TAR

[Richard Harrison]

Tom, K0TAR wrote:
"And aircraft antennas tend to be vertical, at least the ones on the
ground, so orient it that way."

Of course, aircraft need to communicate in all directions around, so
vertical polarization makes sense.

In level flight, VHF aircraft antennas tend to be vertical. See the
submarine Pampanito (at dock in San Francisco as a museum) web page for
SCR 522 specifications. This was an AM VHF radio used in many warplanes
in WW-2. It was supplied with a "1/4-wave vertical antenna". AM and the
VHF frequencies above today`s FM broadcast band, and below the 2-meter
amateur band, are still used for aircraft radio traffic.

Best regards, Richard Harrison, KB5WZI

[adddress@spamfree.com CW]

I have never seen a 2010 so don't know what kind of inputs it has. If it has
balanced inputs, connect the feedline directly to it. If, as I suspect, it
has an unbalanced coax connector, use the 75 ohm balun.

"Jim" <kc7...@hotmail.com> wrote in message
news:781c67d2.04091...@posting.google.com...

[adddress@spamfree.com CW]

I got the impression that he was looking to use the antenna for FM
broadcast. Where did the aircraft come from?

"Tom Ring" <news...@taring.org> wrote in message
news:4143adaf$0$91008$39ce...@news.twtelecom.net...

[Dave VanHorn]

You may not get very good results.
Some VHF TV antennas are built NOT to receive the FM broadcast band, so as
to avoid front end overload. A smart TV antenna designer would also reduce
gain in the aero bands, and the commercial FM bands for the same reason.

It may work well enough anyway.

--
KC6ETE Dave's Engineering Page, www.dvanhorn.org
Microcontroller Consultant, specializing in Atmel AVR

[Tom Ring]

I assume he wants both, given the subject line.

tom
K0TAR

[A-Tech]

CW wrote:
> I got the impression that he was looking to use the antenna for FM
> broadcast. Where did the aircraft come from?

"Tom Ring" <news...@taring.org> wrote in message

news:4144c5fd$0$91003$39ce...@news.twtelecom.net...

> I assume he wants both, given the subject line.

It's a shortwave radio - see this link.
http://mare.radio.tripod.com/8_2010faq.html

...Bryce

>
> tom
> K0TAR

[adddress@spamfree.com CW]

Looks like your right. I read the body of the message but not the subject.

"Tom Ring" <news...@taring.org> wrote in message

news:4144c5fd$0$91003$39ce...@news.twtelecom.net...

[adddress@spamfree.com CW]

I'm familiar with the radio. It has FM broadcast and airband in addition to
shortwave and medium wave.

"A-Tech" <at...@austin.rr.com> wrote in message
news:kN71d.24043$nC5....@fe1.texas.rr.com...

[Tom Ring]

A-Tech wrote:

> It's a shortwave radio - see this link.
> http://mare.radio.tripod.com/8_2010faq.html
>
> ...Bryce
>

I also own one. It does aircraft, FM broadcast, SW, etc.

tom
K0TAR

[G.Beat]

"Jim" <kc7...@hotmail.com> wrote in message
news:781c67d2.04091...@posting.google.com...

Jim -

Let's get back to your query. The broadcast FM band (88MHz to 108 MHz) is
just above Broadcast TV Channel 6 ... so a TV yagi antenna designed for
low-band VHF TV (Channel 2 - 6) or specifically for Channel 6 will do quite
well.

The civil and commerical airband starts above the FM allocation (108 MHz to
136.975MHz) to the beginning of the commerical VHF allocation (136 - 168),
Channel 7 is at 174 MHz

Here is some pertient inforamtion from Bob Colegrove and an older German
posting about this Sony radio Sony 2001D (also known as the Sony ICF-2010).

Bob Colegrove's document Coupling MW and LW antennas to the Sony ICF-2010
http://www.sdxf.org/alfa/dxinfo/coupling_MW_and_LW_antennas_to_the_Sony_ICF_2010.pdf

Building an Antenna mathcing device
http://www.hard-core-dx.com/nordicdx/antenna/special/2010ant.html

About the antenna circuit and external antennas
The following information is from an older posting,
<38EB4AAD...@yahoo.com>:

1.. The ext. antenna socket is "hot", i.e. powered through a 470 ohm
resistence + 100 uH coil. This means that it will deliver approx. 10 mA DC
current to the external antenna circuit. The coil is to prevent "polluting"
the power circuit of the radio with radio frequency signal. Evidently, the
purpose of this arrangement is to "inform" the accessory antenna when the
radio is turned on. In case of the Sony AN-LP1 it turns on the antenna
without need to use the antenna power switch. However, the 7600G will NOT
power the antenna, the 10 mA are not enough to power the amplifier circuit.
The power for the AN-LP1 comes from its own batteries. You can use this
feature with any active antenna by including a proper power-up circuit - a
nice feature if your active antenna is located far away from the radio and
you want it to turn on and off automatically when you use your radio.
2.. You can connect any other antenna (provided it is correctly designed
and installed) to the EXT ANT socket without risking to damage the radio.
However, if the external antenna circuit has low DC resistence, it will
drain some current from the radio. Therefore, you will experiment slightly
higher power consumption from your batteries (up to 10% at normal listening
volume). You can avoid this current drain by including a small ceramic
capacitor (1000 pF) in series with the antenna circuit, however I don't
think it is really necessary.
3.. The 7600G has some basic protection build into the EXT ANT input
circuit. Any static buid-up will be drained off via the power circuit
mentioned in point 1. It also includes a diode pair (1SS123) to protect the
input RF amplifier FET from damage due to too strong signals or an
accidental connection of the antenna to a low voltage AC source. IT IS NOT A
SUBSTITUTE FOR A PROPER ANTENNA GROUNDING AND LIGHTNING PROTECTION IF YOU
USE AN EXTERNAL ANTENNA - YOU STILL NEED TO PROPERLY GROUND YOUR EXTERNAL
ANTENNA AND PROTECT YOUR RADIO, but it builds some margin of safety to
protect the front-end FET - a common problem with the Sony 2001D (2010).
HOW TO DETECT AND REPAIR THE COMMONLY BLOWN TRANSISTOR IN THE SONY 2010
Michael Covington, N4TMI
http://qex.net.tripod.com/mods/sony/mods/sony.txt

Modifications
http://www.qsl.net/wd8das/2010.html

Sony 7600 series radio page
http://stephan.win31.de/sony7600.htm

What ever happen to TV Channel 1 ?
http://members.aol.com/jeff560/tvch1.html

w9gb

[Dave Platt]

In article <p3q1d.87214$3l3.17942@attbi_s03>,
G.Beat <re...@newsgroup.only> wrote:

>Jim -
>
>Let's get back to your query. The broadcast FM band (88MHz to 108 MHz) is
>just above Broadcast TV Channel 6 ... so a TV yagi antenna designed for
>low-band VHF TV (Channel 2 - 6) or specifically for Channel 6 will do quite
>well.

As I understand it, the typical low-band or full-band VHF
television antenna is almost always a log-periodic, rather than a
Yagi. Yagi antennas having a substantial amount of gain are rather
narrow-banded, and won't cover the whole low-band VHF subband
properly. Log-periodics have only a limited amount of gain, but can
have a much wider bandwidth.

I think the only VHF-TV-band Yagi antennas I've seen were
single-channel types.

A full-VHF-band (channels 2 - 13) log-periodic antenna should work
very well on the broadcast FM band, unless it has a built-in FM trap
that cannot be defeated.

--
Dave Platt <dpl...@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[G.Beat]

"Dave Platt" <dpl...@radagast.org> wrote in message
news:10kcca9...@corp.supernews.com...

> In article <p3q1d.87214$3l3.17942@attbi_s03>,
> G.Beat <re...@newsgroup.only> wrote:
>
>>Jim -
>>
>>Let's get back to your query. The broadcast FM band (88MHz to 108 MHz) is
>>just above Broadcast TV Channel 6 ... so a TV yagi antenna designed for
>>low-band VHF TV (Channel 2 - 6) or specifically for Channel 6 will do
>>quite
>>well.
>
> As I understand it, the typical low-band or full-band VHF
> television antenna is almost always a log-periodic, rather than a
> Yagi. Yagi antennas having a substantial amount of gain are rather
> narrow-banded, and won't cover the whole low-band VHF subband
> properly. Log-periodics have only a limited amount of gain, but can
> have a much wider bandwidth.
>
> I think the only VHF-TV-band Yagi antennas I've seen were
> single-channel types.
>
> A full-VHF-band (channels 2 - 13) log-periodic antenna should work
> very well on the broadcast FM band, unless it has a built-in FM trap
> that cannot be defeated.
>
> --
> Dave Platt

Dave -

I nice thing about growing up 60 to 90 miles from VHF & UHF TV stations (and
not that far from Burlington, IA where Winegard still makes the antennas -
and AntennaCraft is next door - where Radio Shack OEMs their antennas) is
that you learn about fringe and deep fringe TV antennas -- and the Radio/TV
stores tried ALL of the types mfg. by Winegard, Jerrold, ChannelMaster, etc.

When Jim mentioned a dipole, reflector and 12 directors ... I have seen this
on a long boom yagi (just like the 2 meter 11 to 18 element antennas) and as
a log-periodic.

A photo is worth a thousand words.

greg