[TowerTalk] 12V through coax to switch antennas remotely

[Don Havlicek]

Being the original "inventor" of this circuitry, I can attest to using 2.5 mh chokes for low bands.
For multi band use, I suggest TWO stages at each end, with two chokes, one 2.5 and one 100, as you noted.
Bypass caps of .001 seem adequate in all positions.
The coupling/isolating caps of .05 work well at both ends.
If building your own, remember to place electrolytic caps and reverse diodes across each relay.  
With good design before you begin, you will have little trouble getting things to work as it should.
Remember, there are FOUR states:
No voltage
Poitive voltage
Negative voltage
AC voltage (closes both relays)
Good luck!
73
Don
N8DE

Sent from my Verizon Wireless 4G LTE DROID

"N2TK, Tony" <tony.kaz at verizon.net> wrote:

>Have a question about the values of the choke to keep RF from the relay and
>the caps for coupling of the signal. In different products I see quite a bit
>of different values of both components.
>
>For the coupling caps I see values from .01-.2uf. It would seem increasing
>the value of the cap reduces the Xc. And for the choke I see values of
>100uh-2.5mh. And it seems increasing the value of the choke also increases
>Xl.
>
> 
>
>My application is for 160M and 80M only with receive antennas.
>
> 
>
>My question - does it really make a difference over the values listed above?
>Do all the values offer enough Xc or Xl to not cause any problems?  Is there
>really a recommended "good" value for the caps and coils? Even 100uh offers
>1K ohms at 1.8MHZ and .1uf is .8 ohms.
>
> 
>
>Still learning.
>
>Tnx
>
>N2TK, Tony
>
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