The GPS seeing the horizon isn't required. Those satellites are filtered out by software. The timing GPSs are designed to be less sensitive to the horizon.
-----Original Message----- From: Chris Albertson <[email protected]> Sender: [email protected] Date: Thu, 25 Oct 2012 10:04:43 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] Timing performance of servers On Thu, Oct 25, 2012 at 9:44 AM, Sarah White <[email protected]> wrote: > Regardless of if I run linux vs bsd vs windows (will be testing multiple > configurations of each, and doing writeups over the next few years as I > test more and learn) I'll need a good external antenna for the new GPS > I'm going to run. > > Anyone think I can get by with anything cheaper than a symmetricom > 58532a antenna? I can probably get one (used) for less than $50 on ebay, > but I'd really prefer to source something more entry-level for closer to > $5 or $10 if possible. Any suggestions? Chris Albertson Redondo Beach, California Location matters a LOT more than the brand of antenna. In an ideal world a GPS antenna needs to see all the way to the horizon in all directions AND it needs to be far way from reflective objects that can cause "multi path". Some times moving a foot or some is enough for an improvement. You will notice that the best timing mode antenna come inside enclosures made to shed water and snow. They are pointy or round on top. You don't need this feature if the antenna is looking out a window. In fact the small patch type antenna might be able to be place close to a window and get a better view of the sky. All that said. These are good and not expensive. ebay #270881742870 I have one of these on a mast and the cable fits inside the pipe/mast. the patch antenna is cheaper see #290739284641 One thing to watch is the kind of connectors. You don't want to have to use a chain of adaptors, N to F to BNC. Those can cost $5 each and certinly do not help the signal. For outdoors I like "N" type as they are 100% water proof. Some types of "F" are too but not all of them. Watch that you get a 5V volt antenna (unless you really want a 3.5 volt type) and get a co-axial type cable. Some have odd-ball multi-pin cables _______________________________________________ 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.
