[amsat-bb] Re: LMR400 or 400UF?
patrickdk at patrickdk.com
Mon Aug 18 18:16:20 PDT 2008
Between your antenna and the preamp is where you want your best coax
at, cause every bit of loss you have there, is lost.
Once it's past the preamp, it will give you good gain, so then it's
just how paranoid you are, as to how much loss you are willing to give
up, to get it into your shack.
If your preamp has a noise level of like 1db, you should be able to
safely loose 1db in coax from your preamp to your shack, and at
40feet, your talking about rg8, maybe mini8 (1.2db I believe).
I'm one of the paranoid people, and normally keep my losses <1db, and
most of them are <.5 db
Quoting Michael Tondee <mat_62 at netcommander.com>:
> I need to rework my 70cm antenna system and was thinking about going
> with LMR 400. I have about a 40 foot run. Is there any real
> advantage to using the ultra flex for the entire run or can I get by
> with a short section of the UF between the preamp and antenna to
> accomodate the rotor turning? How about just using a short section
> of RG8U there instead of the LMR400UF? I'm trying to do this on a
> Tnx and 73,
> Michael, W4HIJ
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