[Elecraft] DC-supply for a preamp?

[Lance Collister]

Hello Cookie,

I am using 200' of 1-5/8" Heliax, and used LMR600 for all my phasing lines.  The 
10' flexible section around the rotor is LMR600UF. I think my total feedline loss 
is less than 0.5 dB. Before I found the free piece of big Heliax, I used free 3/4" 
CATV 75 ohm hardline, which also worked well at keeping the loss down.  7/8" 
Heliax can also frequently be found in these short lengths.

If you can't find any used or end of spool pieces of hardline, new LMR600 has a 
loss of 0.5 dB per 100', so it also is a readily available option.  With all these 
options, and the fact that most people have 6m feedlines shorter than 200' long, 
it really is getting pretty easy to achieve a feedline loss under 1.0 dB on 6m.

GL and VY 73, Lance

On 4/27/2010 5:02 PM, WILLIS COOKE wrote:
> Lance, what kind of coax are you using that only has one dB loss at six
> meters? 7/8" Heliax would do it, but LMR-400 would not unless you could
> keep the run under 100 feet.
> Willis 'Cookie' Cooke
> K5EWJ
>
>
> ------------------------------------------------------------------------
> *From:* Lance Collister <w7gj at q.com>
> *To:* DM4iM <hamradio at vr-web.de>; Reflector Elecraft
> <Elecraft at mailman.qth.net>
> *Sent:* Tue, April 27, 2010 11:25:52 AM
> *Subject:* Re: [Elecraft] DC-supply for a preamp?
>
> On 4/27/2010 2:32 PM, DM4iM wrote:
>  > Elecrafters,
>  > this might be a rig-killer and vy stupid, but....
>  >
>  > Can i power a 6m masthead-preamp by feeding dc via choke and coupling
>  > C's to the KXV3A's in/out sockets (where the elecraft preamp is supposed
>  > to sit), or is this a big NONO?
>  >
>  > Martin
>  >
> Hello Martin,
>
> I think you could do better by simply installing the PR6 at the K3 and
> using low
> loss coax to the antenna. Almost all the 6m EME stations around the
> world use a
> good external preamp in the shack. If your coax cable loss is 1 dB or
> less, you
> will not gain anything by mounting the 6m preamp at the antenna.
>
> You can model this for yourself in the EME CALCULATOR (accessed from the
> EME ECHO
> MODE screen in the old WSJT Version 4). Because the EME CALCULATOR and
> EME ECHO
> MODE were never re-written in the language used in more recent revisions
> of WSTJ,
> that old version is still available:
>
> http://www.physics.princeton.edu/pulsar/K1JT/WSJT498.EXE
>
> I think you will find it much simpler to keep the preamp in the shack!
> GL and VY
> 73, Lance
>
> --
> Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A,
> ZF2OC/ZF8, E51SIX)
> P.O. Box 73
> Frenchtown, MT 59834 USA
> QTH: DN27UB
> TEL: (406) 626-5728 URL: http://www.bigskyspaces.com/w7gj
> LIVE MESSENGER CHAT: w7gj at hotmail.com <mailto:w7gj at hotmail.com>
> 2m DXCC #11, 6m DXCC #815
>
> Interested in 6m EME? Ask me about subscribing to the Magic Band EME email!
> http://6meme.com/mailman/listinfo/magic_6meme.com
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-- 
Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX)
P.O. Box 73
Frenchtown, MT  59834  USA
QTH: DN27UB
TEL: (406) 626-5728   URL: http://www.bigskyspaces.com/w7gj
LIVE MESSENGER CHAT: w7gj at hotmail.com
2m DXCC #11, 6m DXCC #815

Interested in 6m EME?  Ask me about subscribing to the Magic Band EME email!
http://6meme.com/mailman/listinfo/magic_6meme.com