CRT 6900v information

I looking for some information on the CRT 6900v having sourced a new/old stock K40 processor microphone and it’s wired to a 4pin uniden chassis does anyone out there know what chassis the 6900v run so I can get the K40 fitted with.
Dave.

just a word of warning .. the 6900 does not like power mikes .. i had one and a couple of friends also and we could not get the 6900 to sound ok with a power mike .. Fred in the shed on youtube swears by the kpo power mike for the 6900 but we couldn't get them to work propper ... if you do let me know how you did it i would be interested to know ...

Thanks bass 666
I have seen the you tube video that Fred produced. But the k40 is a speech processor there is no adjustment for power just a switch to turn processor on or off.
Dave.

ah ok mate .. good luck with it anyway ..

Can anybody recommend a good radio technician ?

Should be easy to figger out.
Pin 1 is the shield.
Pin 2 is audio.
Pin 3 is TX.
Pin 4 n/c.
But looking around that is uniden wiring so plug it in and tyr it.

Don't forget Alan, there's the unusual method used in these old K40's to power the mic's electronics.


Dave,

You could probably get it working after going through as many stab-in-the-dark suggestions and apparent 'solutions' for it and believe you me there's been plenty over the decades(!)

For me personally, (and this will ruffle some feathers), I never did think the K40 mic lived up to it's apparently legendary status.

As mentioned the 6900 doesn't tend to work too well with a 'power mic' anyway due to the fact that it already has sufficient audio processing built in within its design. (They'll be those that argue the toss about that too never knowing what FM deviation actually means or good audio required for SSB....."Yeah, but this one goes to 11" sort of thinking.)

There's also the matter that the 6900 has a control system designed in so that you can use an Up/Down option on the mic input complicating matters further.


Where the old K40 did excel was on older radios (usually AM types) with very limited audio processing and usually heavier current relay TX/RX switching or later heavy current transistor switching to power the electronics. (Hence suggested mods including diodes and resistors from the power lines to the mic connector.)

The audio boost on older radios obviously helped and due to the design background noise was reduced meaning you could really 'chew' that mic almost good old trucker style.

So obviously worked OK for mobile operations and hence a legend was born.


If I was firing up AM, (maybe SSB), on an old CB in a noisy as heck truck or older vehicle (modern vehicles are fitted with so much sound dampening that some 'pipe' in engine sounds!?!) then I'd certainly use one.

But I wouldn't bother hooking one up to a modern radio.


That's just my opinion, others will have more empirical data......"My mate says it's much louder and getting out better" sort of thing.

However that's the wonderful thing about radio isn't it? People from all walks of life with different opinions, beliefs, thoughts, whatever and either all happily getting on with it or shudder the thought arguing about it all.

I wish you well with it Dave whatever you do. If push comes to shove many believe they're worth the money and it can always be resold.
(Especially to a vintage radio enthusiast.)


All the best,
Victor


(Oh, if it's a modern day Chinese junk copy of a K40.....just pop it in the recycling bin. )

Ha ha on the Chinese copy this is good old American stock Victor but really bought it for my old Cobra 148 which is somewhere between South Africa and Rotterdam at present but not impressed by the microphone that came with the 6900 cheap and too small but K40 is mint as the day it was made but will sell if it becomes surplus to requirements.

Have to agree with Victor on this.
They did work on the old AM sets as long as you fitted the resistor that came with them new.

Yes Alan they are present with the microphone and just as Fred in the shed also thought the original microphone that came with 6900 was like talking with a sock in your mouth I agree 100%.
There isn’t much radio traffic around my QTH mostly truckers on M25 so can’t really get a good report on the radio still waiting for my 10m telescopic mast so just using a mobile antenna on the balcony damn post office strike.

Though so.
I did say that but was worth double checking.