Can I use my jeep radio?

Radio Telephone and Telegraph Transmitting and Receiving Equipment
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YLG80
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Re: Can I use my jeep radio?

Post by YLG80 » Wed May 05, 2021 7:36 am

I have a full HAM license since 1970 and I'm surprised that you have no restrictions regarding the FM modulation bandwidth in your IARU region.
In IARU region 1, the 10 meter band in FM is restricted to a portion of the band and to an FM modulation bandwidth of maximum 20kHz .
I would be surprised that you would be allowed to use these WII radios in the FM sub-band 29.510 MHz to 29.700 with a channel spacing of 20kHz.(repeaters).

These WWII devices have usually a way higher bandwidth of about 100kHz and more...
You would spread your "big mustaches " on 5 adjacent channels :) :) !
Regarding the BC-1000/SCR-300 in the 40Mhz band, I have just measured the FM bandwidth which is also more than 100kHz.
I would say, 120 kHz or something like that, when I yell in the carbon microphone :D ...

IMG_2234s23.jpg

This is the reason why I advise collectors coming to me to modify (reversible) their rig with a MP3 player or even with small PMR RX/TX.

Yves
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Re: Can I use my jeep radio?

Post by N6CC » Fri May 07, 2021 8:27 pm

Hi Yves - Yes, You're right, these old girls are pretty wide especially compared with modern stuff. But that was the technology available at the time.
Our FCC regulations governing emission types & necessary bandwidth are written fairly broadly (pun intended) and in the case of "wideband FM" where authorized, is not codified to a specific deviation limit. (seemingly odd but true). It is left to the licensee to operate using "good amateur practice" and they must eliminate any interference they may cause. As I read it, WFM is therefore not legally prohibited above 29.0 mc if it does not cause interference...Reasonable approach I think. Here are the actual US FCC Regs subset:
--------------------------------------------------
§97.307 Emission standards.

(a) No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice.

(b) Emissions resulting from modulation must be confined to the band or segment available to the control operator. Emissions outside the necessary bandwidth must not cause splatter or keyclick interference to operations on adjacent frequencies.

(c) All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice.
-----------------------
The practicality of actually using this old gear, maybe even outside of a limited "jeep show" etc. is a whole other topic! (Reducing the bandwidth of a WFM transmitter is very simple as you know.. 1 or 2 resistors in the mic circuit...)

Cheers - Tim
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Re: Can I use my jeep radio?

Post by YLG80 » Fri May 07, 2021 11:13 pm

N6CC wrote:
Fri May 07, 2021 8:27 pm
Hi Yves - Yes, You're right, these old girls are pretty wide especially compared with modern stuff. But that was the technology available at the time.
Our FCC regulations governing emission types & necessary bandwidth are written fairly broadly (pun intended) and in the case of "wideband FM" where authorized, is not codified to a specific deviation limit. (seemingly odd but true). It is left to the licensee to operate using "good amateur practice" and they must eliminate any interference they may cause. As I read it, WFM is therefore not legally prohibited above 29.0 mc if it does not cause interference...Reasonable approach I think. Here are the actual US FCC Regs subset:
--------------------------------------------------


Cheers - Tim
N6CC
Hi Tim,
Thanks for that clarification.
Yes I also believe that your regulation is reasonable.
I guess that here in Europe we have less choice because of the population density in our areas.
Or because we are in the Europe described by Ayn Rand :oops: .
Yves
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Re: Can I use my jeep radio?

Post by N6CC » Sat May 08, 2021 8:41 am

Hi Yves - Yes, looks like we all need to rely on some good common sense in these matters. And Common Sense is not all that common these days! hihi
Personally, I would reduce the TX deviation altho reducing the RX IF bandwidth is a much more complex problem.
Cheers from Sunny Kalifornia..
Tim
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Re: Can I use my jeep radio?

Post by Billl » Wed May 19, 2021 12:11 pm

Thanks to all for good - and comprehensive - advice. I think I'll dedicate my $ to something closer to my interest and my jeep - which is
a Chaplain's jeep. I think if I got a radio - any of the ones mentioned - it would just sit in the corner, and get dusty.
Thanks again.

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Re: Can I use my jeep radio?

Post by alpino » Thu Jun 17, 2021 7:28 pm

You might also run into my problem...
About 25x vehicles in my military vehicle club, mostly WW2 jeepsters
I am the only one with a radio, on my M38, it works great, an old 524
did talk to a guy from Oregon, at a military vehicle show, on our radios
excuse my ignorance, hasn't everything modern [including military] digital?
you know SINCGARS and all that... we sure fooled haji with those, he used cell phones
the antenna is cool to fly a S Korean & 48 star US flag from though
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Re: Can I use my jeep radio?

Post by W. Winget » Fri Jun 18, 2021 5:20 am

Look around for one of those old portable Organs, my Brother had one he sold a few years back. tiny things, about the size of a bedside table, issued for services.
V/R W Winget
Looking for 1918 Standard B 'Liberty' truck parts

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Re: Can I use my jeep radio?

Post by YLG80 » Fri Jun 18, 2021 5:56 am

Billl wrote:
Mon May 03, 2021 9:57 am
Is there any practical use for a jeep radio? I found several that need to be restored, and I wondered about buying one and doing so.
But can they be used? Seems like the range is short, the frequency is not anything I could even listen to.
This is what I propose to re-enactors when they ask me what to do with their radios.
This is fully reversible.
BC-1000
viewtopic.php?p=1682688#p1682688

BC-611
viewtopic.php?p=1765511#p1765511
It can be done on many different radios.

My last BC-611 mod like this is on display on a GI mannequin :) !
The owner just pulls the SCR-536 antenna to show to his visitors that the radio is working ...

No license issues, no battery problems, it's cheap, and easy to replicate on several radio sets ... :wink:
Yves
Ford GPW 1943 - Louisville - DoD 12-7-43
serial 164794

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Re: Can I use my jeep radio?

Post by John Neuenburg » Fri Jun 18, 2021 8:11 am

Billl wrote:
Wed May 19, 2021 12:11 pm
Thanks to all for good - and comprehensive - advice. I think I'll dedicate my $ to something closer to my interest and my jeep - which is
a Chaplain's jeep. I think if I got a radio - any of the ones mentioned - it would just sit in the corner, and get dusty.
Thanks again.
One nice thing about being a chaplain is you get to talk to God. Now that is a long range transmission.

Or is it? Long range I mean.
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