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I am having some trouble getting a Dittel KRT-2 VHF to work satisfactorily with a Sigtronics SPA400 intercom. I think (hope!) it's just a question of the internal menu settings of the Dittel also whether pin 12 should be grounded. The manual is not easy to understand and says nothing about using with an external intercom.
I'd be very grateful for advice from anyone who has got this combination to work OK.
I have put a resistor (270 ohm as I had one handy) in the audio lead as suggested by Sigtronics.
Hi Mike,

did you get this sorted please?

I have the same problem with the same equipment.
When using Sigtronics intercom, any chat on the KRT2 radio stops i/c working.

Hoping to use the KRT2 internal software to fix - maybe disable KRT2 i/c function?


Hi Simon, after help from both TQ and Sigtronics I think so, but haven't air tested yet. Give me a bit of time to dig out the notes and I'll post again with the settings to use. The resistor definitely seems necessary and in fact I may increase its value. I have a very noisy environment (Kitfox with 912) if you are in something quieter you may not have this problem.
These are the suggested settings from TQ

VOX 10
INT 01
MIC L05 (starting point, adjust if required)
Pin 12 grounded
R mic input grounded

See how that goes!
When I transmit I get a bit of crackle in the earphones, I don't know if receiving station hears it.
It sounds like ignition pickup. Not investigated yet.
Nick wrote:I have a KRT-2 and I find the internal intercom works just fine, could you not just use that and do away with the Sigtronics?


In my case, I would rather have a convenient knob to adjust the volume than have to do multiple button presses with my eyes on the radio, also removing the Sigtronics and rewiring would have been a fair bit of nuisance.
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Hi Nick & Mike,

thanks for your replies.

Mike: Thanks - will check those settings with the ones I worked out.

Nick: Yes, I certainly could, but;
The Sigtronics i/c works direct from battery, so i/c working for checks & start.
(Not wanting to spike the new £1k radio, so left off until after start!)
I have 4-place i/c on Sigtronics, not sure yet whether KRT-2 would cope?
First trip in a/c with the new radio (and only fourth trip in a/c!), so lots to learn.
Ultimately, yes, I will probably leave Sigtronics off next time & see how I go.

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