Obtained a cobra 148gtl with no output on ssb and approx 3watts AM any ideas whats up with it?
Finals?
The rig recieves fine, it has a 3 position switch and a board inside with three crystals on it and covers a wide range of frequencies but at the moment i haven`t checked which
rgds
dcw

Have you got TX audio on AM ?

Thanks for replying.
i tuned my HF radio to one of the cobra`s channels and I get a carrier on both AM/SSB but no audio

what output power is the carrier on SSB, have you tried FM, what power do you have on FM.



Mark

no output on ssb, aprrox 3watts am, no fm on this old rig

Are you sure the mike's working? Check inside to look for a wire off on the mike gain pot?

If you have a carrier on SSB but no audio then as you have gathered by now its probably just a mic fault.

I probaly should try another mike but will need to wire one up as all mine are four pin.
I checked the mike that came with the rig its cobra badged but a standard mike no gain pot inside just the ptt switch.
Initially the radio was way off on usb recieve but i have tweaked that back onto frequency.
It doesn`t look messed about with inside all the cores look fine but has i said in the original post it does have an add on board which is a bit of veroboard with the components on it.
The rig receives fine and seems pretty sensitive.
Will check another mike out and report back
rgds
dcw

Lets hope so will try another mike and report back
Thanks to you all for the help
rgds
dcw

Thought you posted in a previous reply that you had a ( carrier on both SSB and AM ...........

maybe it is as nicky has said its just the microphone.



Mark

Sorry, I meant a wire off the rig's mike gain pot.

Nicky is a girls name thank you very much

Oh i do appologise old man........

Nick, what do you think of that book ?


I found it ok, but there could have been a bit more real info in there though.




Mark

Well it is the mike, wired up another one and away she went,you live and learn
Worked out its frequencies does low,mid,high +alphas bit complicated with all the different switch combinations to get to these frequencies but the rig appears to be fully working now.
trouble is don`t know what to do with it now,if it had fm/uk40 I would put it in the van but I know my limitations
Thanks again gents for your help
rgds
dcw

I have never heard about carrier on SSB.
Can anyone explain to me how a sideband-transmitter can send a carrier, and on top of it all, no modulation ?
Ironic question, but a sideband signal contains no carrier.
That's why it's called sideband, coz it contains the additive (USB) or subtractive (LSB) resulting frequency between the frequency of the AM carrier and the modulation-signal.
The carrier are then filtered out and the sum/difference-signal are transmitted.
That's why you won't get anything out of an SSB-transmitter as long as there's no modulation (audio) applied.
At least thats what I learnt during my 3 years at tech school.
And here's an explanation of SSB: http://en.wikipedia.org/wiki/Single-sideband_modulation