Running wire

[mattsmith]

Wasn?t sure where to put this, hope this is the right spot. I am running wire in my 8A and have a few questions. I am mounting the ADAHRS for the sky view behind the aft baggage compartment and have found a good way thru the center section for the wire up to the display but it means the wirer from the ADAHRS will run right next to the RG 400 for the comm and transponder. Is this ok, the wirers will run together for about 4'? I don?t know if I can add holes to the center section and if I could, I would rather not.

Questions #2 can I run two COMM and one transponder antenna wires all together, as in where they are touching? three Separate runs of RG400 of course.
Thanks matt

 

[mattsmith]

I had to call Stein for some other parts and asked him, he said no problem. Thanks Stein.

 

[Bullseye]

Matt,

Thanks for posting Stein's reply. I'm a long way from wiring, but this is really helpful for some of us newbies.

 

[elippse]

The Times Wire and Cable catalog shows that single braid cable, such as RG58U, has a leakage of -48dB/ft at 100 MHz and -41dB/ft at 1260 MHz. Double-shield RG400 shows -85dB/ft at 100 MHz and -76dB/ft at 1260 MHz. If you run two RG400s side-by-each for one foot, and the one is with a transponder radiating 200W, +53dBm, and the other is a comm run, it will receive a signal of 53 -2 X 76 or -99dBm. The front end thermal noise power, kTB, for a bandwidth of 10 kHz and T=300K, is -134dBm, and with a 3dB front end noise, the receiver should be able to detect a signal at least 3dB above the receiver noise level or -128dBm. This radiated/received noise from the transponder to the comm at -99dBm is 19dB stronger, which might give some noise on the wide-band front end amplifier/mixer/crystals. It is best to keep high power transmitter signals separated form low level receiver inputs.