Hi, AT575-142TTW-TNCF-000-RG-41-NM
Not all 575 antennas eat the same power. Its the RG in the part number above that specifies 4.2V to 15V DC power for the internal LNA. This is the most common option - but there are others. -- Björn <div>-------- Originalmeddelande --------</div><div>Från: Bob Camp <kb...@n1k.org> </div><div>Datum:2015-02-27 20:21 (GMT+01:00) </div><div>Till: Discussion of precise time and frequency measurement <time-nuts@febo.com> </div><div>Rubrik: Re: [time-nuts] XL-DC was Re: time-nuts Digest, Vol 127, Issue 33 </div><div> </div>Hi One important caution on antennas: The 575 is quite happy with anything from 5 to 18V as a feed voltage and only pulls 35 ma. There are antennas out there that don’t like voltages over 6V. There also are antennas on the market that pull well over 50 ma. If the “original” box sourced 12V to the antenna and triggers as “overload” around 50 ma, the 575 will work great with the box. If you plug a modern timing antenna (= 5V version) into the box the antenna may be damaged and / or the over current may trigger. There also are 3.3 V antennas out there, but they are rarely seen in timing applications (yet). Simply put - the 575 is a great antenna and it will work on a lot of stuff. The problem is not at all with the antenna. It’s with the stuff specified to work with it. You have no way of knowing if it’s a 12V gizmo or a 5V feed. The same issue can come up with downconverter feeds. They often put +12 on the feed to run the downconverter. It’s best to put a DVM on the feed before attaching a nice new $1,500 antenna to it …(or even a $20 one) Bob > On Feb 27, 2015, at 1:11 PM, Russell Rezaian <r.reza...@earthlink.net> wrote: > > I can confirm there are at least two common varieties of the XL-DC GPS RX > board. > > One uses a "normal" GPS antenna (no down-converter, provides DC on the > antenna line for an amp in the antenna, the typical antenna provided seems to > be an AeroAntenna AT575 variety, but I suspect other antennas that are > similar should be fine). The specific antenna part I have is: > AT575-142TTW-TNCF-000-RG-41-NM > > It's been a while since I last decoded that part number but it's a very > easily re-useable general use GPS antenna with an integrated RF amp. Works > over a fairly wide range of DC supply voltages and claims a slightly higher > gain than some other standard timing GPS ice cream cones. > > There are also versions of the GPS module for the XL-DC that use a GPS > antenna with an integrated down converter that is actually physically part of > the antenna provided. > > The down converter antenna is normally a single integrated unit. The part > numbers I see on one I have handy are 140-614 (TrueTime) or Model 142-6150 on > the Symmetricom label. > > I don't have any details for the voltages or whether there is a reference > frequency provided for the down converter style receiver. > > I have seen some suggestions that they also had a dedicated down converter > module that could be used with "normal" GPS antennas, but I don't have any > details on that option. > > If you have a RX module that needs the converter antenna there should be a > clearly visible little label indicating this on the module itself near the > antenna connector. If you don't have that label the RX should work with most > GPS antenna systems (and also with most antenna splitter systems too). > -- > Russell > > Al Wolfe wrote: >> I have an XL-DC and it has an internal GPS receiver in it. It supplies and >> monitors 5 volts to a BNC antenna jack for an external amplified GPS >> antenna. I don't know what the internal GPS engine is but doubt if it is >> anything special. >> >> The manual describes the down converter system as an option. >> >> Al, k9si >> >> >>> Boy I ran out to mr google and did a search and now I am wondering if some >>> versions of the xl-dc just used a plain old GPS antenna. It sure looks like >>> that could be the case. The manual does say down converter. Maybe it >>> changed over time. >>> Regards >>> Paul >>> WB8TSL >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
