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CB FM Mode

AudioShockwav

Extraterrestrial
Staff member
Apr 6, 2005
7,660
5,604
593
Sierras Near Yosemite National Park
I might change my mind if I make a direct FM contact but maybe FM hasn't caught on around here yet. CBs in general aren't used that much around here. I'll probably just have to get more patient. Thank for bearing with me !
It just became legal, it will take a while before the masses will even have there hands on these radios so I doubt you will hear it day to day.
If you can find someone around that has FM and you can make a solid confirmed contact you will might be surprised how well it works.
For years exports have had FM but it was a mode little used here in the US.


73
Jeff
 

whiteastro

Sr. Member
Feb 22, 2019
601
700
103
71
It just became legal, it will take a while before the masses will even have there hands on these radios so I doubt you will hear it day to day.
If you can find someone around that has FM and you can make a solid confirmed contact you will might be surprised how well it works.
For years exports have had FM but it was a mode little used here in the US.


73
Jeff
I'll be honest with you I sometimes think the people around here are a little more laid back and slow to embrace different technology. The place is a little behind the National Average in a lot of areas. Just my Humble Opinion !
 

whiteastro

Sr. Member
Feb 22, 2019
601
700
103
71
There was a dude on .385 calling on FM today. 20 over big signal. Said he was running some big power out of east Tennessee. I guess he was trying to pull dudes off of ssb...? I worked him easily. He had several guys calling.

I applaud his efforts to draw guys to FM..don't know if .385 is the place to start..
Yeah I have to get more projects done so I have more time to devote to radio. Hard to learn when you have too many Irons in the Fire.
 
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AudioShockwav

Extraterrestrial
Staff member
Apr 6, 2005
7,660
5,604
593
Sierras Near Yosemite National Park
I'll be honest with you I sometimes think the people around here are a little more laid back and slow to embrace different technology. The place is a little behind the National Average in a lot of areas. Just my Humble Opinion !

I can kind of relate to that feeling.
I live Mariposa county, population 2,700.
Historic Gold Town, the Courthouse was built in 1858, still in use today.
People about had a heart attack when they opened a Subway here.
What? Subway in our little town? Heaven forbid!
People really got upset.
There is not a single stoplight in the town and if you even mention such a thing you will draw the ire of the community let me tell you.
If you install lighting in the parking lot it has to look vintage 1850's or they won't approve the permit.
As far as infrastructure, they kind like being stuck in the mid 1800's here.


73
Jeff
 

whiteastro

Sr. Member
Feb 22, 2019
601
700
103
71
I can kind of relate to that feeling.
I live Mariposa county, population 2,700.
Historic Gold Town, the Courthouse was built in 1858, still in use today.
People about had a heart attack when they opened a Subway here.
What? Subway in our little town? Heaven forbid!
People really got upset.
There is not a single stoplight in the town and if you even mention such a thing you will draw the ire of the community let me tell you.
If you install lighting in the parking lot it has to look vintage 1850's or they won't approve the permit.
As far as infrastructure, they kind like being stuck in the mid 1800's here.


73
Jeff
Sounds all to familiar to these people clinging to the past. Wages in this area have always been behind the National Average. I sometimes wonder how life might have been if I stayed in the aircraft repair line of work. Oh well had some fun along the way. LOL
 
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Woody-202

Sr. Member
Sep 5, 2018
567
901
103
66
It just became legal, it will take a while before the masses will even have there hands on these radios so I doubt you will hear it day to day.
If you can find someone around that has FM and you can make a solid confirmed contact you will might be surprised how well it works.
For years exports have had FM but it was a mode little used here in the US.


73
Jeff

Every time the FM mode is used, Major E.H. Armstrong gets a little tickle ;)
 

whiteastro

Sr. Member
Feb 22, 2019
601
700
103
71
Well I pulled the Little Thomas radio out of my car today and replaced it with my NOS Uniden PC-122 to try it after I turned down the dead key and changed my antenna. Needless to say the radio was Dead today. Sometime a guy just can't win. LOL
 
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Rick330man

WDX 404
Mar 16, 2013
687
970
103
Florida Keys
We use CB down here as a way to communicate from boat to house when you get beyond cell phone range. If you have a boat with a generator, a cabin, various electronics, etc. then you'll get a lot of interference. FM is far less vulnerable to the QRO and QRM that can wreak havoc with your AM and SSB reception.

I'm not parting with my AM/SSB gear, but I have already picked up a President Thomas AM/FM unit for the house and a President Randy II walkie talkie for the boat. The only complaint I have is: why did the FCC wait so long to allow FM on CB? It should have been with us all along. Better late than never, right?
 

ljh505

Active Member
Nov 29, 2020
66
166
43
Albuquerque
The only complaint I have is: why did the FCC wait so long to allow FM on CB?
Who knows. I think most of the European countries had FM in their regulations by the mid to late 1990s, but at that point compact/pocketable mobile phones were taking off in the U.S. for mobile car communications, so the U.S. CB market was primarily trucking, and AM on Ch. 19 was "good enough".

I found it strange the FCC initially denied the FM petition of the manufacturers a few years ago when other Part 95 FRS and GMRS services have been FM all along, and was glad that the decision was appealed and eventually approved.

I think allowing long-distance "skip" communication (SSB most useful for this, of course) and FM modulation with PL/CTCSS/DCS has made CB interesting again after many years of only using it for interstate travel road conditions on AM Ch 19. I'm eyeing that Wouxun KG-S72c handheld FM to pair with a President FM capable radio for base/walkabout when camping.

https://www.buytwowayradios.com/wouxun-kg-s72c.html
 

NZ8N

Sr. Member
Dec 25, 2017
445
710
103
58
The problem with FM in CB's or 10 meter radios is that the Squelch is AGC actuated, unlike a true FM radio which uses high frequency noise actuated Squelch, to go "Full Quieting" to open the Squelch. An FM detector (descriminator or other) generates "random" white noise when there is no signal present, as it has nothing to "lock" onto. Then when there is a carrier to lock onto, you get "Full Quieting", and it opens the Squelch.


A circuit like this or similar would do the job nicely, but there would need to be some way to disable the AGC derived Squelch (AM or SSB modes) and tie into the Squelch pot to switch from AGC Squelch to FM Noise actuated Squelch. Maybe by grounding the Squelch Gate base pin and having another gate transistor (FM only) do the function when in FM mode.
 

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