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Old 31st Jan 2017, 9:15 pm   #61
SiriusHardware
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Default Re: All about CB radio

A couple of the smaller radios from my collection:

1) Colt 355, CB/27/81 UK version

The red 'inspected' sticker and 'Made in Korea' on the rear are an immediate giveaway that this was made by Maxon. I'm not really a great fan of Maxon manufactured CB radios but I've always liked their habit of putting the year and month of manufacture on the rear plate. This radio was owned by a family member from new, from about 1983. I have the original manual, but sadly not the box. It still works. I have never seen any other example of this model. Quite a low serial number on this one - I wonder how high they went?

2) Midland (Kernow) 77-104, UK CEPT (PR 27 GB) version.

This one is from a little later than the Colt 355, perhaps mid-late eighties. I believe the same model number (77-104) was used for both the UK CB/27/81 version and this version, with only the 'band identifier' logo to distinguish between the two externally. This one was bought 'working' from an auction site, and does now actually work. Somewhere along the line the original mounting bracket has been lost and a new one fashioned, quite neatly, from what appears to have been the carrying handle of an old cassette recorder.
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Old 31st Jan 2017, 11:16 pm   #62
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I wonder if the channel 9 thing was part of the UK spec? Every set I have seen seems to have this feature, as well as the usual 10dB Tx power reduction switch on the 27/81 models.
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Old 31st Jan 2017, 11:34 pm   #63
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Quote:
It's a shame you aren't a bit closer as I have ring binders full of issues of Citizen's Band and CB radio magazine from the years immediately before and after the UK legalisation date.
It's nice to know that there are some of these mags preserved somewhere. I bought quite a few of the mags in that era too but I had a clearout a few years ago. I can remember some of the adverts, especially the ones for the Stalker IX FDX with the CB27/81 sticker on it. It seemed to be advertised by lots of dealers at the time.

I replaced my Sharp 40CH AM CB with the CB27/81 version of the Superstar 360 some time around 1982 and I remember seeing all the adverts and trying to find one at a low cost.

Quote:
I wonder if the channel 9 thing was part of the UK spec? Every set I have seen seems to have this feature, as well as the usual 10dB Tx power reduction switch on the 27/81 models
Most of them had a CH9 button but I can remember that the Cobra 21X FM didn't have a CH9 button.

I have a soft spot for the Cobra 21X FM as it looks similar on the outside to the AM radio that was in my mate's brother's car all those years ago. It wasn't a very good CB as it suffered badly with overload. However, this was one radio I never managed to buy for myself. I always wanted one and I would have put extra filtering in it to help with the overload. It was a really neat little radio, full of charm

The economy 40FM was a very basic radio with no s meter and I don't think this had a CH9 button either. It was a horrible radio with really poor Tx audio quality. Some of the basic 134 radios probably didn't have a CH9 button. eg the Rotel 220 or the Harrier CB? The classic Maxcom 4E was another one with no CH9 button and this radio was very similar to the Cobra 21X FM although the 4E was black. It was not a highly regarded radio and was often portrayed as one of the worst CBs on the market. But there were far worse radios than the 4E back in those days
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Old 31st Jan 2017, 11:45 pm   #64
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The -10dB feature -was- a specific part of the UK specification. If your base station aerial was over a certain height above ground you were supposed to reduce your power.

..Yes.

If you went to the trouble to put a decent base station aerial up in the air, you were legally required to cancel out any advantage you had gained by reducing your output power by -10dB. I don't think it happened very often, although people often did drop to low power for purely local conversations, to lessen the likelihood of attracting robotic quick-fire 'On the side' contacts from a wider area.

Channel 9 for emergencies, on the other hand, pre-dated UK CB. It was an established convention on more mature CB systems, especially in the USA where there was a fairly serious civil organisation called REACT which was a little bit like the UK amateur radio RAYNET organisation.

They undertook to monitor channel 9 around the clock where possible - if it all sounds a bit earnest and goody-twoshoes, remember this was completely pre-mobile-phones so if you were involved in a vehicle accident, a CB and a calm, responsible, competent person with a landline telephone on the other end could be your only way of summoning medical or mechanical aid.

Unfortunately nothing (to my knowledge) ever got going on the same scale with the same national degree of co-ordination in the UK, although some efforts were made.
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Old 1st Feb 2017, 12:15 am   #65
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Quote:
Originally Posted by G0HZU_JMR
But there were far worse radios than the 4E back in those days
Ah, that's a good subject. For me, the award for absolutely the worst ever UK CB by a long mile goes to... the Fidelity 1000.

Fidelity seem to have hedged their bets when it came to sourcing their CB radio models. The 1000 was a dreadful one-off oddball which I can't remember ever seeing badged by anyone else. Foremost among its many faults was an inability to even produce the full 4W output. It used to put out 2.5W if you were lucky.

The Fidelity 2000 on the other hand was a brilliant radio - Jeremy won't agree - because it had the very respectable Cybernet 134 chassis in it. In fact the 2000 is a good radio to search for if you want a radio with a 134 chassis but you don't want to pay the price of a York 863 / Binatone 5-star / Rotel RVC240, because the Fidelity 2000 is probably one of the least well known 134 chassis radios.

The Fidelity 2001 I've always assumed was another incarnation of the Amstrad 900-901 / Harvard 402 chassis, but from what Jeremy was saying in an earlier post maybe that wasn't the case?

What was in the Fidelity Home Base? I can visualise its external appearance but I can't remember which chassis it used.

I was talking to a distant friend of mine about a week ago and he mentioned that he is busy re-acquiring all of the landmark radios he owned during his misspent youth - not the actual ones, that would be impossible - but examples of each one. Among those he's recently acquired is a pristine, boxed example of a Cobra 19X (original AM version). I agree they had a certain character, something about the way they looked, even though they just had the standard Maxon AM chassis lurking on the inside.
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Old 1st Feb 2017, 2:16 am   #66
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Look up Cheiza or Elftone to see similar to the Fidelity 1000 radios
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Old 1st Feb 2017, 9:22 am   #67
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Oh, NO. I remember those now.
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Old 1st Feb 2017, 10:13 am   #68
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I can vouch for the quality of the Binatone 5star unit owning one and using it in my car on a regular basis.

The build quality is really very good.
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Old 1st Feb 2017, 2:47 pm   #69
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Default Re: All about CB radio

I had a Fidelity 2000 back in 81' and I remember it being a nice rig, connected to a DV27 on a water tank in the loft. Being high up I could easily get out to Essex from south London. Weren't they one of the many incarnations of a Uniden chassis?

Hard to believe that back then, in London at least, the channels were full up every night, some nights one couldn't find elbow room till way after midnight !

I occasionally listen around 27MHz on my Kenwood R1000, and it's all but empty of CB down here, save for a 'net' of 2 or 3 chaps who pop up from time to time. How things have changed?
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Old 1st Feb 2017, 5:58 pm   #70
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Was the Fidelity 2000 the large silvery rig with the mic gain and RF gain pots along the front and the very "clicky" channel knob? I think I still have a couple of those. I will now have to scuttle off to the shed to find out!
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Old 1st Feb 2017, 7:13 pm   #71
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Default Re: All about CB radio

Daft question, but is CB still used? It's before my time (but only just!) as I wasn't born until September of 1982.
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Old 1st Feb 2017, 7:16 pm   #72
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Quote:
Originally Posted by ITAM805 View Post
I had a Fidelity 2000 back in 81'... weren't they one of the many incarnations of a Uniden chassis?
Definitely not. Cybernet 134 chassis in the Fidelity 2000.

Mind you, odd things sometimes happened. According to one source at the time there was a 'fake' version of the (normally Uniden built) Cobra 148 GTL-DX multimode which had a Cybernet multimode chassis inside.

If you had laid out money for a 148 expecting to find the usual Uniden chassis inside, you would have been inconsolable if you then found that somebody had put a Cybernet chassis in it, such was the rivalry / partisanship between those two camps.

Quote:
Originally Posted by Biggles;
Was the Fidelity 2000 the large silvery rig with the mic gain and RF gain pots..?
Attached, a web image of a Fidelity 2000 - (a beautiful example, I must say).
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Old 1st Feb 2017, 7:30 pm   #73
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Daft question, but is CB still used? It's before my time (but only just!) as I wasn't born until September of 1982.
Most definitely it's still used: mainly by truckers [travelling the motorways I hear many trucker-nets where Eastern European languages - Polish, Lithuanian, Romanian - are being used] and also in small groups of farmers foresters or hauliers. Near me there's a new education campus being built and this is involving shifting many thousands of tons of rock and earth: the haulage-company doing this work have CBs in their trucks and they use it to let the site-manager know when an empty truck's about to arrive for the next collection. I guess there are around ten trucks doing a 'shuttle' service on this job, all coordinated by CB.

Farmers also use it a lot - particularly during harvest - to coordinate grain trailers and combines.
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Old 1st Feb 2017, 7:34 pm   #74
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Daft question, but is CB still used? It's before my time (but only just!) as I wasn't born until September of 1982.
You missed out on all the fun. When you were little, no truck was complete without at least one CB aerial, and you could look around any housing estate and pretty soon see an 18ft vertical CB aerial bolted to the side of a house or teetering precariously on the top of a heavy scaffolding pole.

Today, certain niche groups, like 4*4 drivers - the kind who actually do drive their vehicles offroad that is - invariably have a CB aerial on their vehicle and they are quite often seen on cars which are towing caravans, especially if there are two or more of them in procession. Farm vehicles (Tractors, Combines, etc) also often have them. But usage among the general public is probably at a very low point now.

For myself, CB is something which I do when I'm on holiday - I select a radio from my collection and take it with me, usually to north or west Wales or the north west of Scotland. Although there is very little local activity in those areas, their distance from the southeast UK means that summer sporadic 'E' propagation can create a radio bridge between the two areas, in which case I can often find myself talking to people in Kent when I'm parked up somewhere near Portree (Skye).
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Old 1st Feb 2017, 7:34 pm   #75
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Off roaders use it too, cheap robust short range comms..
 
Old 1st Feb 2017, 7:58 pm   #76
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Quote:
The Fidelity 2001 I've always assumed was another incarnation of the Amstrad 900-901 / Harvard 402 chassis, but from what Jeremy was saying in an earlier post maybe that wasn't the case?
The 1981 Fidelity 2001 is the same inside as the 1981 Amstrad 901. I think the main board is the same with the same board number but with minor differences to do with the difference in s meter type. I always assumed they were both made by Cybernet because they have the same PCB number and the main PCB uses the same numbering system as Cybernet. eg PCMA and the schematic drawing style and wording is very similar.

My take on this was that the Fidelity 2001 and the Amstrad 901 were new generation Cybernet rigs designed specifically for UK FM use but they were also designed to be cheap. So on the outside they look like the poor relation to the Cybernet 134 radios but the 134 radios are really based on old school export AM/FM radios but with the UK PLL system and FM only. Both were flawed in their own way(s) but I preferred the 2001 Fidelity to the 2000 model. But others will disagree.

However, I think I read somewhere that later versions of the Amstrad may have been manufactured by someone else? So they had different internals? I never saw one of the later ones though.
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Old 1st Feb 2017, 8:37 pm   #77
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Actually (and I'm just looking now) Cybernet board numbering invariably took the form

PTBMnnnA0X

...where nnn is 092, 096, 106, 134, 135, 121, 125, 131 etc.

Sometimes the suffix would be ...'COX' but the format never wavered.

I have a nice article here originally from the December 1981 issue of Radio and Electronics World (R&EW) which is a four page 'technical' review of the then just-released Amstrad 900 / 901. It includes the circuit diagram and discusses the circuit section by section. One interesting statement from the article is that the LA1230 FM / IF IC is a Sanyo clone of the CA3089, but that it, unlike the original CA3089, can produce usable meter output from 455Khz.

The circuit diagram style is certainly very similar to Cybernet's, although that could just be down to both designers or draughtsmen having used the same off the peg circuit drawing package, stencils or rub-down transfers - it's hard to know exactly what they would have used at the time.

I never saw any version of the Amstrad chassis other than the version you would know, with the 'stone resistor' used to limit the RF output power.

Incidentally I've just remembered another badge worn by the chassis used in the Amstrads, Harvard 402, and Fidelity 2001 : 'Mustang'
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Old 1st Feb 2017, 9:12 pm   #78
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Quote:
Actually (and I'm just looking now) Cybernet board numbering invariably took the form
PTBMnnnA0X
I think they also used PCMA for some radios? Have a look at the Nato 2000 CB27/81 radio. This is also a Cybernet radio and it uses PCMA001S and the Fidelity 2001 has the board number PCMA002F. I think it also uses the same numbering system as the Fidelity 2001 for the display PCB and other minor circuit boards like the channel change board, eg PCLDxxx and PCSWxxx.

The 200 channel HyGain 5 radio also used this type of PCB. I recall that some 200 channel variants had 4 banks of 50 channels rather than the normal 5 banks of 40 channels and they had strange channel numbers because of this.
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Old 1st Feb 2017, 9:34 pm   #79
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Originally Posted by G0HZU_JMR
I think they also used PCMA for some radios? Have a look at the Nato 2000 CB27/81 radio. This is also a Cybernet radio and it uses PCMA001S and the Fidelity 2001 has the board number PCMA002F.
Very true, now you point it out. I had some experience with the 121 chassis (good) and the later 125 chassis (surprisingly poor receiver compared to the 121) but I only ever saw one Nato 2000, so it wasn't the first thing that jumped into my head. I've just been looking at the Nato diagram, though. I respectfully agree that you may have something there.

I never liked the radios with blocks of 50 channels, since it went against previous convention and only caused confusion. The logical thing to do (and it eventually happened, as soon as technology allowed) was to move from a channel readout to a frequency readout.
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Old 1st Feb 2017, 10:24 pm   #80
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The PCMA board is also listed amongst the Cybernet radios on the Cybernet Export Service Manual cover although this manual was produced by Lou Franklin rather than Cybernet.

It might be that these radios were built at another factory or maybe there's another reason for the different PCB number. The schematic for the PCMA001S looks like a classic Cybernet export schematic so it would have to be a deliberate copy/fake if it wasn't Cybernet.

There were other radios that used the same board as the Fidelity 2001FM, I can remember the Transcom variant with the annoying Tx and Rx LEDs and also the Spinneytronic version of the Amstrad 901. But I don't think I ever saw a Spinneytronic other than in pictures or adverts.
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