S

Slats

Active Member
Hello all,

I have two basic electrical questions about my bird.

1) I have a handheld radio due to transmit problems I was having. There is a junction in the co-axial cable running from the radio to the antennae. Can I install a bnc tee junction (does such a beast exist) and use both the panel mount radio and portable off the same antennae?

2) the transmit issue was caused by a broken wire on the ptt. The wire to the ptt is two strand with shielding. The wire is so short that it would be easiest to add small extensions to each strand up to the button. Does the signal transmitted to and from the ptt really need to be shielded? Could I run unshielded one inch extensions?

Thanks in advance for the help.
 
I don't believe shielded wire is required for PTT, so not sure why it has been used. I am certainly not using shielded wire for my PTT and have had no issues on any of my planes/radios in the past.
 
Slats said:
1)... There is a junction in the co-axial cable running from the radio to the antennae. Can I install a bnc tee junction (does such a beast exist) and use both the panel mount radio and portable off the same antennae?



2) the transmit issue was caused by a broken wire on the ptt. The wire to the ptt is two strand with shielding. The wire is so short that it would be easiest to add small extensions to each strand up to the button. Does the signal transmitted to and from the ptt really need to be shielded? Could I run unshielded one inch extensions?
Click to expand...

re: 1)Not a good idea. You upset the impedance balance of the system. You could install splitter, but you will reduce received signal strength by half to each radio. What you want is an RF switch, so you can select either radio to be connected to the antenna.

re: 2) Should not be a problem at all. Shielding normally protects radiated signals from emanating. These signals are "alternating current" of some frequency. Your PTT signal is DC. No radiation... therefore no shielding required. There is a remote chance that the shielding might be protecting from energy coupled IN. Not likely though, so give it a go.

Don




Thanks in advance for the help.
 
Slats said:
Hello all,

Can I install a bnc tee junction (does such a beast exist) and use both the panel mount radio and portable off the same antennae?
.
Click to expand...
No. Using two radios on one antenna gets complicated. Let's just leave it at that.
Slats said:
Could I run unshielded one inch extensions?
Click to expand...

Yes. A shield is not necessary on the PTT circuit.
 
Thanks to Wayne

I installed that switchbox and finally got around to testing it out today.

It works like a hot ****!

At 1500 agl my handheld picked up a vor at 90 sm!

Unbelieveable!

Thanks again!!
 
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