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AR15.COM
12/26/2009 8:03:55 AM EDT
All the mobiles at Universal radio ask for 13.8vdc that is fine if the car is running but in an ecomm box the batteries will be at 12.7vdc or so. Will this be a problem? Would it cut the output?


Bear with me as I am just now licensed and don't have a radio yet.
12/26/2009 8:35:52 AM EDT
[#1]
Almost radio I've ever seen will run down to 10 or 11 volts, most will still receive at 9 volts but not transmit.

eta: also note as voltage drops so does output power.
12/26/2009 9:36:20 AM EDT
[#2]
you need to read the rest of the specs. most say 13.8v +- 10-15% depending on the maker. find a radio you like then check out the owners manual. that should tell you how low the voltage can get before it stops TXing.
12/26/2009 9:45:33 AM EDT
[#3]
Yeah, it will keep running until at some point, when you transmit, the voltage drops enough that the radio turns off.

I had a Yaesu FT-897 that would transmit even with voltage, on transmit, in the 11.2-11.3 range.  On receive it was still just over 12 volts.  At that point I quit for the day.
12/26/2009 11:42:08 AM EDT
[#4]
note:  voltage in tubed equipment is really touchy.  One field day we operated a TS-520S (solid state rx/tubed TX for those that dont know) on deep cycle battery.  We were doing the hunt and peck around a band so our actual duty cycle was low.  After about 90 minutes of operation (40 or so contacts so maybe 10 minutes of transmit at the most) we were told we were off freq. After some checking, sure enough we were drifting badly but the battery still had plenty of power left in it.  Had to fire up the generator to get back in the game.
12/26/2009 3:00:08 PM EDT
[#5]
Yup, tube/hybrid rigs drain power fast, especially in transmit. My old Icom 735 would run down to about 10.5 volts before it would distort on transmit. At that point it was only producing 50 watts wide open.
12/30/2009 11:48:51 AM EDT
[#6]
This for stable voltage http://stores.tgelectronics.org/StoreFront.bok