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  #9  
Old 03-13-2012, 04:33 AM
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Originally Posted by pro151 View Post
Well how about that! Out of all of the crap I have seen, built and done over the years, this is the first time I have heard of or seen this mentioned.

Thanks for the lesson!
You are welcome but I never would put any voltage on my coax as it is just another problem that may happen.

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  #10  
Old 03-13-2012, 06:34 AM
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I have no problem with injecting a DC control voltage on my coax cable if it is done proberly with the right blocking capacitor on each end and the series coil for the DC to flow thru while preventing RF from getting back into the power source. The only issue is that you are very limited in the number of relays you can switch this way. Typically you are limited to three antennas with one being on when the power is off, one operates from a pos. voltage and the other from a neg. voltage.
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Old 03-13-2012, 01:16 PM
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Originally Posted by Captain Kilowatt View Post
I have no problem with injecting a DC control voltage on my coax cable if it is done proberly with the right blocking capacitor on each end and the series coil for the DC to flow thru while preventing RF from getting back into the power source. The only issue is that you are very limited in the number of relays you can switch this way. Typically you are limited to three antennas with one being on when the power is off, one operates from a pos. voltage and the other from a neg. voltage.
If the blocking cap fails what would the result be to the transceiver?

I just prefer not to take the risk of adding a potential problem that would result in catastrophic damage to a transceiver or associated equipment. One less thing to worry about.

Other ops do run the control voltage on the coax.

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Old 03-13-2012, 01:30 PM
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Most radios already have series blocking caps in the output filter sections already and they already have shunt coils to ground so any failure of multiple caps would result in the DC voltage flowing thru one of those coils to ground possibly burning out the coil and causing it to open up. This of course assumes that the operator was irresponsible enough to power the relays from an unfused high current power source. Normally one would use fuses and/or a low current power source like a wall wart cube to power the relays.
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Old 03-13-2012, 02:56 PM
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Fair enough and all that was said is true, most radios have the safety components.

The discussion about using control voltage on the coax or separate is moot.
Either way works, one just has more risk than the other.

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Old 03-13-2012, 03:50 PM
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Originally Posted by wavrider View Post
Fair enough and all that was said is true, most radios have the safety components.

The discussion about using control voltage on the coax or separate is moot.
Either way works, one just has more risk than the other.
True, I will grant you that one in a million is a much greater chance than zero.
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Old 04-18-2012, 07:42 PM
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Ok got a quick question. Trying to figure out what wire to use to run up to the switch box to power the relays. Im thinking about running one wire for ground and then 2 for the power. the relays say 2 amps on them and i will be running 12 volts to them. Would rotor wire handle 12 volts passing through it to power the relays and have them stay on or would i need something thicker? What would you all recommend for this project?

Thanks in advanced. Mark

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  #16  
Old 04-22-2012, 05:43 PM
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Default 12v relay mounting

Wave,

How did you mount the relays?? Or should I say the rf between relay and so-239's

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