Club 80-90 Forums

It is quite likely the Sterling.

These devices have a digital voltage boosting circuit to send more volts than the alternator supplies, to the battery to charge it faster. The simple digital circuit (known as a "switch mode power supply") produces a series of "square wave" pulses that generate harmonics that can get through any suppression, and into your CB set. Most 12 volt DC to 240 volt AC mains inverters do exactly the same for exactly the same reasons. For more (technical) info on switch mode power supplies, see = http://en.wikipedia.org/wiki/Switched-mode_power_supply" onclick="window.open(this.href);return false; esp paragraph 3 re interference.

There is little point in trying to put any filters in the wires as the interference will be "radiating" from the Sterling and getting into the CB via the aerial. It's a bit like the opposite of what used to happen when CB's interfered with the next doors TV !

If I am right, temporarily disconnect ALL of the wires to the Sterling and see if the interference goes away.

Let me know, along with computers "it's my job"

I'll give it a bash. Will take a bit of doing though as I'll have to hook the starter battery back up as it'll need a 15min drive to test if it's made any difference.

Funny thing is that I know at least three other people that have CBs and sterling units and I've not heard anyone else having this trouble.

Is there anything else it might be?

First rig was a President Veep, lovely bit of kit
Best rig I ever had was an old Cobra 148gtl dx with a "flick it" switch to a load more channels Should never have got rid
Used to have a walkie talkie when I push-biked to work with a twig on the handlebars

Was a member of the 2 local clubs as well
HBC Hinckley Breakers Club
CBC Central " "
Happy Days

v-lux wrote:.
Funny thing is that I know at least three other people that have CBs and sterling units and I've not heard anyone else having this trouble.

Ah, might not be that then, but worth a "test" as described.

v-lux wrote:Is there anything else it might be?

Always frustrating over the net, if I was there I bet I could identify it in minutes

Try a temporary earth to the metal case of the sterling unit (unless it is already bolted to the body of the van in a "metal to metal" fashion.

Try an alternator suppressor, from the like of Halfords etc These fit onto one of the bolts on the alternator and the wire goes to the main red terminal on the alternator, takes 5 mins to fit, DISCONNECT battery first !! (note, take care not get a distributor suppressor, in fact NEVER fit one of those to any vehicle with electronic ignition).

Have you recently checked the SWR of your aerial system ? A bad connection here can cause the coax to "collect" interference as well as drastically reduce performance.

You going to Bustypes ?

p.s. It just occurred to me that a less than perfect regulator pack one the alternator could produce that rev related high pitched whining and might be affected by time or heat (as you say it only starts going it after e few minutes driving). These are cheap and easy to fit.

Anyway, Hairy Bikes is back on

i have an audioline 341 cb from the 80s in my van and its still going strong and works perfectly,my mate also has a rotel 240 and we use them when we go on meets and such

Its arrived...
Mucho thanks...

Gonna install today as the waterboard thinks its a good idea to dig the road up and so we cant got out..

toomanytoys wrote:Its arrived... Mucho thanks...

Gonna install today as the waterboard thinks its a good idea to dig the road up and so we cant got out..

Is this going on the Syncro or the Velle ?
If the Syncro just wondering what aerial you use ?
Reason I ask is we always used to recommend a 4ft "Dial-a-Match" as they work well and are VERY strong against damage by tree branches etc.

Syncro and have a springer that seem to stand up to the abuse on the landy's etc..

Installed, nobody on air locally, or so it seems... (havent heard anyone, or even a crackle.....) but looks like the swr meter isnt working properly.. seems to be affected by how its held and moved, like a dodgy connection.. the cal pot prob is furred up and moving it back and for a lot hasnt cleaned the track.. unless the cb is fubared......

I'll prob pop and see the Mockster next weekend if he's about..

I should have joined in on this one! At the last "proper" outing (Surrey Lanes?) the CB performance - RX and TX - had fallen off really badly. When I first did the install for Coney Farm everyone commented on it's clarity and signal strength. SWR hasn't changed, pretty good at about 1.7-1.8 so could it simply be a bad earth for the unit?
I did have to re-do a few earth spade terminals at the crowns last winter, could I have accidentally made the radio supply one worse?

I really think Im missing something with this thread. I bought a CB, fitted it, switched it on and spoke to people ...... I dont have patch leads or SWR meters or any of this stuff.

Seems to be picking stuff up on a run out today, but havent tried to speak to anyone..

Andrew.. yeah, prob most new stuff will work fine out of the box.. but a check with a SWR meter makes sure there are no anomolies and thus protects the transmitter..
My CB is approx 30-35 years old.. (it was second hand when I got it..) it hasnt been used for prob 29 years.. and I dont know how well its performing and if its remotely matched to the ariel... I'd rasther check it than wait for the fizzle fizzle POP!!!!..........

toomanytoys wrote: if its remotely matched to the ariel... I'd rather check it [the swr] than wait for the fizzle fizzle POP!!!!..........

Note the only thing that gets damaged is the final output tranny (often = 2SC2166) they are dead easy to fit and cost about £3

Re the newer, less than 6 years old(ish) sets, they use a different transistor that has inbuilt protection against the excessive voltage build up caused by poor SWR or faulty coax leads and so very rarely fail.

Also those large spring base aerials tend to work and have a good SWR "out of the box" on most "normal" installations.