A question about CB Radio - Page 1
Forum section: electronics / rf-microwave

author: McBryce
author_rank: Super Contributor
timestamp: March 20, 2017, 07:38:36 pm
content: Hi radio people,back in my very early days I was a CB enthusiast, however I haven't been on the air since the late 80's. Just recently, while visiting my parents I unearthed two of my radios from back then. One is a typical 40 channel car/truck device (Realistic TRC-427), the other is a 40 channel handheld device (GE 3-5979A). Both seem to still work fine. Does anyone anywhere in the world still use CB? Are they of any use to anyone? Are there any hard to find / rare parts inside that people may be craving after to fix some other radios? If not I will scrap them for parts, although there's not much inside that I would use today. But I thought I should ask first before I get the screwdriver to them.McBryce.

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 20, 2017, 08:03:05 pm
content: It would seem like the most definitive for you in your location would be to simply throw an antenna up and listen for a few weeks to see if there is any traffic in your neighborhood.Like you, I haven't used it in maybe 40 years, but my understanding is that while it has lost most of its popularity, at least here in the US (and Canadia?) it is still popular with long-haul (inter-city) truckers. In particular, channel 19 is traditional for communicating road conditions (and location of law enforcement officers). Dunno whether that practice/tradition ever made it over to the Continent? I would at least listen to channel 19 for a few weeks before dissecting the gadgets.Of course, these days, a $20 SDR dongle in an old retired PC could scan the entire band and show you visually what is happening in 11M or any other band for that matter.

author: McBryce
author_rank: Super Contributor
timestamp: March 20, 2017, 08:16:16 pm
content: Yes, truckers did use CB over here too, but I think it died out here earlier than in the states. I left the handheld CB on channel 19 for the whole of Saturday without hearing a single transmission. Unfortunately I don't really have any way of listening with the vehicle device (which would probably have a much bigger range) without laying cable and putting up an antenna. I suppose I could throw together a simple dipole antenna in the garden if I can find the bits to make one.I suspected that these are beyond their sell-by date, but I don't like scrapping things for parts when they still function fully.McBryce.

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: March 20, 2017, 08:22:09 pm
content: Agree it would be worth having it set up for at least several weeks before deciding what to do with it. A ground plane antenna is simple to make and could be temporarily rigged up.Around summer you can often get sporadic e propagation and be talking to people 1000 - 2000 km away on the CB. This is probably easier than it was with less crowding.Another thing you could do if you're into radio experiments is to use the CB as a tunable IF (especially if the CB does AM/SSB). A 7 MHz crystal is good for this, giving both amateur and 41m shortwave broadcast reception. A suitable converter is very simple (2 transistors) and can be built in a night. Eg

author: McBryce
author_rank: Super Contributor
timestamp: March 20, 2017, 08:32:07 pm
content: One is FM only, the other AM only. I don't do anything radio related these days, which is why I doubt I will ever have any reason to use them again.McBryce.For reference, these are the two devices we're talking about. Not exactly highend devices (not pictures of mine) not even back then:https://i.ytimg.com/vi/bQnrzCQcX0s/maxresdefault.jpghttp://d2ydh70d4b5xgv.cloudfront.net/images/b/1/ge-40-channel-cb-citizen-band-transceiver-handheld-radio-walkie-3-5979a-c9f66f242f3ede783e3558d9ad3d778f.jpg

author: voltsandjolts
author_rank: Unknown
timestamp: March 20, 2017, 09:50:08 pm
content: I recommend a trip down memory lane, just key the mic and shout random CB slang at anyone whos listening!https://en.wikipedia.org/wiki/List_of_CB_slangKojak With a Kodak = Police Officer running radarCurse you, internet, for destroying CB!

author: McBryce
author_rank: Super Contributor
timestamp: March 20, 2017, 10:12:29 pm
content: I was tempted to call QSKBut I resisted.McBryce.

author: G0HZU
author_rank: Super Contributor
timestamp: March 20, 2017, 11:37:14 pm
content: Here in the UK there appears to be a healthy market for used CBs amongst collectors. On ebay they fetch quite high prices and I guess a lot depends on the model and condition and exclusivity.I spent a lot of time on CB when I was a student many years ago and I still have quite a few old CBs here. Most of mine are the old export type and I have several of the classics still boxed and original. eg I have several mk1 and several mk2 Cobra 148GTL-DX radios that are original and boxed. I suspect that these CBs are worth quite a bit of money today.Your best bet might be to put them on ebay and see what happens?

author: CatalinaWOW
author_rank: Super Contributor
timestamp: March 21, 2017, 02:09:54 am
content: CB radios are still sold in virtually every truck stop I've been in, so they are are obviously still in use here in the US. You don't see the antennas on the trucks as ubiquitously as they used to be, but if you look there are quite a few of them around.Ebay is the easiest way to drag a little value out of these. Just don't expect much. If you look on Ebay you see new modern gear selling for $40 or so. But there is old junk also selling for $10 or more.

author: McBryce
author_rank: Super Contributor
timestamp: March 21, 2017, 08:26:44 am
content: There's probably more than $10 worth or parts in them that I can use. Just the channel select switch alone could be useful and probably cost me more if I were to buy one.McBryce.

author: CJay
author_rank: Super Contributor
timestamp: March 21, 2017, 12:19:18 pm
content: Quote from: McBryce on March 21, 2017, 08:26:44 amThey're both AM and on FCC frequencies only unless they've been modified to suit the local market.The channel switch will be an odd thing, the switch will output a series of N-Codes, quite what they'll be depends on the PLL inside the radio, some of them are straight binary but it may count up or down and will definitely have some odd gaps and swaps (for instance channel 3 and 4 are separated by 20KHz on the FCC bands so the N-Code will skip and again there's weirdness happens around channel 22-25 which means the codes reverse), some are BCD and will suffer the same skips and jumps as the binary ones, some will use the same codes as the 7 segment displays (ROM locked PLLs), others will use something different again (another ROM locked variant).Not particularly easy to repurpose.'old junk' if it's in good condition can fetch surprising amounts on eBay if it's in good condition, especially if it can be sold as tested.Personally, they owe you nothing, scrap them for parts if you can't be bothered with testing and selling, if nothing else they'll be fun to take apart and work out the details of but I'm not sure what bits you'll harvest and find useful if you're not going to build more radio stuff.

author: McBryce
author_rank: Super Contributor
timestamp: March 21, 2017, 12:48:09 pm
content: You're right. I was pretty sure that the Realistic TRC-427 was FM, because I definitely owned an FM Transciever back then, but I've checked an it's definitely AM too. Then I suspect my old "Cobra" was the FM unit, but I couldn't find it during the visit. I possibly sold it a long time ago and forgot.I hadn't checked the details of the rotary switches, but if they are as you say, then they're not much use. As for condition of the units: The GE Handheld looks like it has just been taken new out of the box, the front of the Realistic is in very good condition, but the painted body looks a bit battered. Either way, looks like they are both heading towards my "For spares" box.McBryce.

author: Hawke
author_rank: Contributor
timestamp: March 23, 2017, 09:42:26 am
content: Gday It's not that the concept died out but rather they migrated to UHF to get away from the noise on 27meg and to take advantage of repeaters in rural areas. The CB bands are quiet but most trucks here and in Canada still have a 27 meg rigs lying dormant somewhere in the cab. Also prior to trunking it was easy to add police receive as most of the radios from the late 80s onward had micro controllers with channels stored in an EPROMs so adding extras was relatively simple compared to manipulating a PLL with wiring, switches etc. Here in Australia the UHF CB band was expanded from 40 to 80 channels a while back but calling it an expansion is stretching it a little bit. They went from 25kc steps in channel separation down to 12.5kc so again it was a bit of simple reprogramming without the need for front end tuning. I still have a lot of good CBs that I couldn't part with like The President Adams or another rig from Asia that had FM instead of AM and the one that got me started into radio and electronics the Roberts RCB 55. You might find a collector for the TRC with Tandy no longer being around and it's vintage now so you never know. Cheers

author: raspberrypi
author_rank: Frequent Contributor
timestamp: March 26, 2017, 02:48:46 am
content: Quote from: McBryce on March 20, 2017, 08:32:07 pmI had one of those handheld ones when I was 10. Took a whole bunch of double A's had a ridiculous long 6' antenna, and I could never talk to anyone on it. I think it was only three watts.Now the CB is garbage, the people just yell racial obscenities to each other in this weird fake southern accent, trying to out stupid each other. The epitome of a white trash Trump voter. They also run some stupid 100 watt amplifiers so you couldn't use a four watt radio if you wanted to, they just key over you.I bought that radio at service merchandise and to "upgrade" the radio I brought it back where the sales man plugged it in to see if it was working; with the wrong polarity and blew it up, but then blamed it as defective and gave me credit towards a new cobra CB.

author: CJay
author_rank: Super Contributor
timestamp: March 26, 2017, 07:13:32 am
content: 'Stupid 100W amplifiers'Have a look for 'superbowl', those guys are running thousands of watts and you can often hear them here in the UK, spread over about a dozen channels either side of their fundamental and hammering the signal meter to the endstop.CB is dead, I used to run a small repair shop for them and still repair a few for local users just because I enjoy working on them but it's a very small market now.

author: Bicurico
author_rank: Super Contributor
timestamp: March 26, 2017, 08:45:48 am
content: EDIT:I seem to recall that CB is no longer in use and those frequencies have been repurposed for other use. The equipment may no longer be operated or sold (new) at least in Portugal or even Europe.What really happend in Portugal: some years ago, authorities changed the law and CB devices have to comply with 1W/4W output power. Also, devices have to be certified and need to be sold with portuguese manual. So from night to day all existing CB devices were made illegal, as they transmitted more than that, were not certified and even if they were modified to be within specs, you could not sell them. People just lost interested in this. I guess something similar happend in other EU countries.PMR at 446KHz came as a replacement for non licensed amateurs.You should inform yourself before transmitting any test signal, as you might get in trouble, if your devices transmit more than the allowed power.The other reason CB and even PMR is dead for truckers is of course mobile phones with flat rate contract.PMR is used by private security, staff at shopping malls or events and for campers in the country side. Here these small PMR devices outperform CB at cheaper prices. In some areas people have setup relay networks.I leave these links:https://thekeystruckers.com/2010/03/04/death-of-the-c-b-radio-or-how-we-communicate-now/http://radiosurvivalist.com/radio-articles/is-this-the-death-of-cb-radio/http://www.radiocb.com/main/menus_main/banda_do_cidadao/04_esclarecimentos_comprador/default.htm(Portuguese)https://translate.google.com/translate?sl=pt&tl=en&js=y&prev=_t&hl=pt-PT&ie=UTF-8&u=http%3A%2F%2Fwww.radiocb.com%2Fmain%2Fmenus_main%2Fbanda_do_cidadao%2F04_esclarecimentos_comprador%2Fdefault.htm&edit-text=&act=url(Google translated to English)Regards,Vitor

author: madires
author_rank: Super Contributor
timestamp: March 26, 2017, 10:24:18 am
content: The current regulations for Germany are 40 channels AM (4W) and SSB (12W), and 80 channels FM (4W) which is reduced to 40 channels in the near of any border. CB usage is quite different between regions, in my region it's nearly dead. The scanner picks up mostly some Bergfunker (mobile CB radio operator with RF amp on a hill) and rarely a local CB. Despite a highway nearby, no truckers. There are gateways connected via internet, also gateways from/to other bands. I see more activity on Freenet and PMR than CB.

author: MagicSmoker
author_rank: Super Contributor
timestamp: March 26, 2017, 10:43:16 am
content: I found one good use for an old CB radio: ad-hoc/informal testing of EMC immunity.

author: grumpydoc
author_rank: Super Contributor
timestamp: March 26, 2017, 01:47:13 pm
content: I suspect that what really happened to CB was the Internet.

author: retrolefty
author_rank: Super Contributor
timestamp: March 26, 2017, 02:27:37 pm
content: Quote from: grumpydoc on March 26, 2017, 01:47:13 pmNo, cell phone killed CB for all but the survivor crowd.

author: grumpydoc
author_rank: Super Contributor
timestamp: March 26, 2017, 02:39:01 pm
content: Quote from: retrolefty on March 26, 2017, 02:27:37 pmOK, partly, but phones don't exactly replace the many-many aspect of chatting on a CB channel.T'internet offers that nicely, although have to be able to type

author: retrolefty
author_rank: Super Contributor
timestamp: March 26, 2017, 04:21:53 pm
content: Quote from: grumpydoc on March 26, 2017, 02:39:01 pmWhile driving a big rig? That is not even legal in my State.

author: grumpydoc
author_rank: Super Contributor
timestamp: March 26, 2017, 04:38:17 pm
content: Quote from: retrolefty on March 26, 2017, 04:21:53 pmWhich might explain why truckers are one of the few groups that still use CB

author: kc2skg
author_rank: Newbie
timestamp: March 26, 2017, 05:14:32 pm
content: It was the caliber of the "many-many" that drove me away. Too crowded to get any range, language was terrible, and a lot of the "advice" offered was deliberately incorrect. Not a group I wanted to converse with. Most things are cyclic. Over the past year I have noticed an increase of CB antennas on vehicles in my area. Maybe its time to dig out my old Royce and see what's out there.And I still don't have a cell phone...

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 26, 2017, 06:13:45 pm
content: Quote from: kc2skg on March 26, 2017, 05:14:32 pm"a lot". Two words. "Allot" is a verb.10-4

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 26, 2017, 10:06:10 pm
content: Quote from: McBryce on March 21, 2017, 08:26:44 amAt some point in their evolution (clearly long before digital frequency synthesis), they used an elaborate array of quartz crystals and a weird sequence in the channel select switch to create all 23 (or later 40) channel frequencies. I got the impression that many of the channel selector switches were not simply SP23T or even BCD switches. So even the channel switch might be an oddball component.Rather amazing the things that we did mechanically back then are considered antique and obsolete today.

author: W9GFO
author_rank: Regular Contributor
timestamp: March 26, 2017, 10:47:39 pm
content: Quote from: grumpydoc on March 26, 2017, 04:38:17 pmI have mixed feelings about CBs. Back in the late '70s and early 80s we were quite active in REACT which was a club that used CBs for monitoring channel 9 for emergencies as well as other disaster preparedness things. This was in rural Nebraska. I started trucking in '88 or '89. The CB was very useful, but there was a lot of "trash talk". When I quit trucking about ten years ago CB usage was still valuable for communicating but the ratio of trash talk to civil communication was dismal. The huge advantage that CB has is that it is like one big party line. If you need some information you simply ask and chances are good that someone will respond. Can't do that with a cel phone.What I find disappointing is that the trash talk has discouraged many from monitoring the CB, so the likelihood of getting a response is nowhere near as good as it used to be in the good ole days, which is a shame.

author: McBryce
author_rank: Super Contributor
timestamp: March 27, 2017, 09:06:09 am
content: Quote from: raspberrypi on March 26, 2017, 02:48:46 amYes, it has a 6 foot whip antenna with a closed coil in the middle, and it takes 8x AA Batteries which don't last very long if hit the transmit button (Possible Bateroo test candidate?). I left it on each time I was at my workbench this week and not a single transmission was received, so it definitely looks like nothing is happening around here. I'll scrap them for parts and find out if the channel select switch is really some mechanical wonder or whether I could use it for something else.McBryce.

author: CJay
author_rank: Super Contributor
timestamp: March 27, 2017, 09:07:50 am
content: It's a mix of all sorts of things, CB in the UK was really popular when there was an element of 'sticking it to the man' but legalisation gave it a huge boost, tens of thousands of people bought radios and within a year an awful lot of them were in cupboards, lofts, sheds or on the tip.It declined from there with the rise of mobile phones and the 'net, in the UK telephones were *expensive* back in those days because there was one state provider and no competition, you weren't allowed to use your own equipment on their network, it was a criminal offence and you had to be rich to have a second line just for social use so CB was a cheap way to communicate between friends in your town, nowadays, messaging services like Whatsapp etc. are the favoured way for groups to chat and offer privacy and all the other benefits of a 'net messaging service.The massive boost given to mobile phones by SMS was a big reason why people didn't take up CB, why bother waiting for your mate to be on air when you could text him any time, plus the rather naff image of American truckers from the 70s (think Convoy) and CB, radio in general, has become a bit of a joke to the general public nowadays.I still listen in to CB occasionally (usually only when repairing one) but if there's anyone to listen to they're usually drunk, stoned, swearing at someone, selling drugs or some combination of, it's not really worth the effort.These days I prefer to spend my radio time tinkering with and building things for ham bands or repairing things for people, gives me far more enjoyment.

author: CJay
author_rank: Super Contributor
timestamp: March 27, 2017, 09:39:19 am
content: Quote from: McBryce on March 27, 2017, 09:06:09 amIf you want a 'straight' channel change with BCD coded outputs you're probably going to be out of luck, even the UK ones which had channels with no 'gaps' or hops mostly used an odd coding method but there were some UK radios which used sequential binary and one that (I think) used sequential BCD, if you have a use for one I have some here and could post you one for the cost of P&P?I'd be interested to see the guts of both radios as I can't find much or any information about either so if you can spare the time to take a couple of board pics that'd be great.Shame to scrap them, especially if the handheld is in good condition but...

author: McBryce
author_rank: Super Contributor
timestamp: March 27, 2017, 10:24:46 am
content: I'll post some pictures at the weekend when I have time. I've no current use for the channel select switches at the moment. I'm not specifically looking for them, I'd just keep these ones in case I have some use for them in the future.If you are interested in having either unit (for use or for parts) make an offer.McBryce.

author: CJay
author_rank: Super Contributor
timestamp: March 27, 2017, 10:51:56 am
content: Sadly postage would make it far too expensive and as you've already said, they're cheap enough that they're worth more for parts than any offer I'd make.Shame to scrap them but as you've discovered, there's not much use for them other than as a curiosity (and they're likely illegal to use anyway) or parts.

author: Codebird
author_rank: Regular Contributor
timestamp: March 27, 2017, 11:38:11 am
content: QuoteI have in my collection of parts a PWM power controller from an old microwave oven. It's purely mechanical in operation - a combination of microswitch, cam-tracker offset by the control slider, and a very unusually shaped cam. It generates a fixed-frequency PWM signal with an adjustable duty cycle from 0 to 100%.

author: McBryce
author_rank: Super Contributor
timestamp: March 27, 2017, 07:22:26 pm
content: Ok, here's a few Analogue circuitry pR0n pics from the devices. Sorry for the crap lighting, I only get to really use my lab at the weekend.First the TRC-427. The last picture is a close-up of the channel selector footprint. Looks like it is something exotic with multiple layers of switches.McBryce.

author: McBryce
author_rank: Super Contributor
timestamp: March 27, 2017, 07:24:58 pm
content: And the Handheld device. Unfortunately this is one of those devices that requires desoldering of components and jump wires to get inside properly.McBryce.

author: Lord of nothing
author_rank: Super Contributor
timestamp: April 02, 2017, 08:00:15 pm
content: Quoteyou mean Mhzl.Haha and there are a lot of people with China Radios aka Baofengs.Worker on the Construction side, Kids, Babyphones,... thats why I switched to some Digi with more output fun.QuoteWho is by the European Law illegal. What i rember the law say "for mobile use only". That mean your the Repeater is not in a moving Car your get screwed up.QuoteWho isnt free in the rest of Europe.QuoteThe same here in Austria. In the Past you had an 1/4 Line or worse a 1/8 Line that mean 4 or 8 Phones share one Telephone line no not in the Apartment, the hole Apartment building share one line!!!So CB ist still in use more SSB I would say. <12W legal is quite nice.I have a huge Problem with the ffuu..... Powerline Adapter the Send from ~2Mhz to 30Mhz. I could not get any clear Signal.

author: madires
author_rank: Super Contributor
timestamp: April 02, 2017, 08:17:28 pm
content: Quote from: Lord of nothing on April 02, 2017, 08:00:15 pmPlease seehttps://www.bundesnetzagentur.de/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/SpezielleAnwendungen/CB-Funk/CBFunk-node.htmland read CB-Funk Allgemeinzuteilung (German text).

author: Lord of nothing
author_rank: Super Contributor
timestamp: April 02, 2017, 08:23:11 pm
content: PMR446 not CB.

author: james_s
author_rank: Super Contributor
timestamp: April 02, 2017, 08:36:45 pm
content: Well you've got at least two of them, you could give one to a friend and use it to chat just for fun. If there's so little activity on the air you're not likely to have to share the band with anyone else.

author: Lord of nothing
author_rank: Super Contributor
timestamp: April 02, 2017, 08:38:17 pm
content: He can use it only when nobody use Powerline and other stuff there.

author: madires
author_rank: Super Contributor
timestamp: April 02, 2017, 08:41:40 pm
content: Quote from: Lord of nothing on April 02, 2017, 08:23:11 pmGateways are also allowed for Freenet and PMR in Germany.

author: Lord of nothing
author_rank: Super Contributor
timestamp: April 02, 2017, 08:49:20 pm
content: i dont care are about Freenet.http://www.erodocdb.dk/docs/doc98/official/pdf/eccdec1505.pdfCheck the official German speaking Documents.For Austria:https://www.bmvit.gv.at/ofb/marktueberwachung/fsb/funkschnittstellen/fsbln.pdf

author: Howardlong
author_rank: Super Contributor
timestamp: April 02, 2017, 09:21:11 pm
content: As we seem to be reminiscing....I remember getting a legal rig soon after CB was legalised in the UK. For protectionist reasons, the UK gov decided on an incompatible FM system on 27MHz, also slightly offset from the AM channels so it meant a diferent PLL chip would be needed.There was also a 900MHz band, but I don't know anyone who used that.ISTR we needed to purchase a licence too.A few months later I took my ham test, and other than very very occasional listening, I've never bothered with CB again.Many folks used CB as a stepping stone to getting a ham licence in the UK back then, I am sure there was a similar influx in other countries as they introduced it.

author: Lord of nothing
author_rank: Super Contributor
timestamp: April 02, 2017, 09:23:39 pm
content: QuoteGSM Phones?

author: Howardlong
author_rank: Super Contributor
timestamp: April 02, 2017, 09:34:37 pm
content: Quote from: Lord of nothing on April 02, 2017, 09:23:39 pmIt's not just GSM phones around 900MHz. The UK 934MHz CB band lasted until 1999.

author: CJay
author_rank: Super Contributor
timestamp: April 03, 2017, 04:39:39 pm
content: Quote from: Howardlong on April 02, 2017, 09:21:11 pmI'd love to know the full reason for that offset, I've heard various stories about it, including incompetence and civil servants getting mixed up with VHF channel spacings.Quote from: Howardlong on April 02, 2017, 09:21:11 pmThere was indeed, I knew nobody until recently when I was shown a full 934MHz setup,complete with power/SWR meter, beam and a mint condition Cybernet Delta 1, still in working order but useless and yes, we did need to buy a licence but the fee was dropped after a few years, just requiring registration.

author: james_s
author_rank: Super Contributor
timestamp: April 03, 2017, 04:53:39 pm
content: In the US there is a 900MHz ISM band today, it's used by some cordless (landline) phones, and various wireless devices, my weather station uses 900MHz to transmit from the sensor suite to the console.

author: Lord of nothing
author_rank: Super Contributor
timestamp: April 03, 2017, 05:39:06 pm
content: How about the 800Mhz Band?