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 <[email protected]> Sender: [email protected] Date: Mon, 21 Jan 2013 20:19:47 To: Discussion of precise time and frequency measurement<[email protected]> Reply-To: Discussion of precise time and frequency measurement <[email protected]> Subject: Re: [time-nuts] "Better" gps antennas than a Symmetricom 58532A On Mon, Jan 21, 2013 at 6:59 PM, Hal Murray <[email protected]> wrote: > > [email protected] 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 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
