[Elecraft] DC-supply for a preamp?

[WILLIS COOKE]

Martin, it is a common idea.  The antenna tuners and remote relays that use only the coax use the idea.  The big danger is connecting the injection port incorrectly and putting the 12 volts on your transceiver.  I have a dead TS-850 waiting for repair because I connected the injection port backwards for my MFJ Antenna Tuner.  I have been holding off on this note because I hoped for official work from Elecraft, but I have seen none, so here is your "Take it for what it cost free advise".  The comments about putting the amp at the transceiver have merit.  Personally, I don't have an external preamp and I have about 3 db loss in my cable, but I make some nice 6 meter contacts.  The people with more equipment no doubt hear better than I.
 Willis 'Cookie' Cooke 
K5EWJ 




________________________________
From: DM4iM <hamradio at vr-web.de>
To: Reflector Elecraft <Elecraft at mailman.qth.net>
Sent: Wed, April 28, 2010 6:18:37 AM
Subject: Re: [Elecraft] DC-supply for a preamp?

Hello all,
thank you for all the info about losses in a coax cable,
but the original question was if this is a good or a bad idea.
Lots of qsb, so it disappeared in the noise. :-)

I've been thinking about it myself, my conclusion is: no good idea.
Even if the K3 passes the supply voltage to it's antenna jack, bad
things can happen if you forget to switch the supply off, when you
change antennas, switch to your dummyload, you name it.
So it is a big NONO.

Martin

--

73 , DM4iM
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