[time-nuts] "Better" gps antennas than a Symmetricom 58532A

[lists at lazygranch.com]

It is possible that the noise figure of the preamp is better than that of the gps. This is especially true if the GPS predates SiGe parts being common place.

I never ran any heliax, but isn't the idea also that it will last longer than coax.

-----Original Message-----
From: Chris Albertson <albertson.chris at gmail.com>
Sender: time-nuts-bounces at febo.com
Date: Mon, 21 Jan 2013 20:19:47 
To: Discussion of precise time and frequency measurement<time-nuts at febo.com>
Reply-To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Subject: Re: [time-nuts] "Better" gps antennas than a Symmetricom 58532A

On Mon, Jan 21, 2013 at 6:59 PM, Hal Murray <hmurray at megapathdsl.net> wrote:

>
> albertson.chris at gmail.com said:
> >  The Heliax will only do good if the length of the run is long.
>
> I don't understand that.  What does the type of antenna have to do with the
> length of the run?


You are confusing "heliax" with "helix".    The latter is an antenna type
the former is a way to build coax cable with a hard copper later in place
of the coper braid.

For most normal cable runs of say 20 to 40 feet using exotic cable is not
just ified be cause the difference in signal strength is only a dB or two
but if you are building a tall microwave tower where the equipment room is
100+ feet from the antenna then the losses add up and things like Haliax
might be worth it.

Yes you could use an amplifier and cheaper cable, most everyione facing a
longer run would do that.  It works.  But in theory amplifiers always add
some noise so in theory if you can sawp out and amplifier of some big-bucks
cable you migh gain something.   But at short distances it is moot because
there is nothing to gain.    This is why I said it only makes sense for
longer runs where cable loss matters

Of course the cheaper way to deal with cable loss is to move the GPS
receiver.  Maybe place it in the attic right under where the antenna cable
comes through the roof?


-- 

Chris Albertson
Redondo Beach, California
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