Hi, the model of bias tee referenced below works well, with very low insertion loss, down towards 1GHz, despite the manufacturer's specifications:
http://www.ohiomicrowave.com/things/hwe32biasteetranscept1000204C.pdf Item #270287524274 on a well known Internet auction site, lists the "Buy-It-Now" price as $19.95 for brand new units. If you are worried about return loss, I can provide plots for GPS frequencies. Performance really falls off below 500MHz, where the insertion losses approach 50dB! For the money, the build quality is superb. HTH Darren PS. I have no commercial interest in the sale of the items; I'm just a happy user. 2009/9/3 <[email protected]> > > In a message dated 03/09/2009 17:04:50 GMT Daylight Time, > [email protected] writes: > > Seems like a good idea, a lot simpler and cleaner than the other > suggestions. > Sounds like a data problem, I'd suspect your VSWR meter or cabling first. > Maybe your VSWR meter does not like diodes especially if it is not running > current thru them. > And if you are running current thru them to approximate the GPS antenna, > whatever you're doing to run the current thru them is making the reading > unhappy. > Did you try just the BNC adapter with just a short inside? And with just > the cap inside? Better cap? > And the finial test does it work OK despite the VSWR reading? > > > ----------------------- > Ummmmm > > Not really a very good idea, we're talking about two silicon diodes in > series with each other and then used as the central conductor of a coax > adapter > at nearly 1600MHz. > Aside from the discontinuity caused at the diode junction itself, consider > how fine the wire might be inside that diode and consider the magnitude of > the uncompensated impedance changes caused by this, the high VSWR shouldn't > come as too much of a surprise. > Then consider what two rectifying diode junctions are going to do to your > RF signal regardless of the VSWR. > > Burt's suggestion of fitting the diodes inside the antenna stands more > chance of success, assuming they are fitted correctly, but I would still > suggest an external biased T as the most practical answer if one still > insists > on using the 3.6v antenna. > With 5v antennas so widely available though there really doesn't seem to be > much good reason for doing this anyway. > > regards > > Nigel > GM8PZR > _______________________________________________ > 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.
