Sure sounds to me like the distribution amp does have some sort of shielding problem, in effect.
Are the power connections (whether AC or DC) properly filtered? Are all the coax connectors' bodies well-bonded to the metallic enclosure? You might want to try sniffing with a small diameter (~1 inch) loop on the end of a flexible coax cable going to the SA. Sniff connectors, power input(s), seams on the case, any other penetrations in the case (like a display?), etc. Dana On Sat, Jul 13, 2019 at 12:00 PM Jerry O. Stern <jster...@att.net> wrote: > I have been using a Tbolt and TAPR TADD-1 for a few years, mainly as an > external reference source for my workbench equipment. Just got a SDR radio > kit (Ubitx) and trying to calibrate the local oscillators found this > annoying substantial 10MHz signal heterodyning with the LO's (45MHz and > 12MHz). Taking a look on my SA with just a broad band telescopic antenna > in the SA input, I see a 10MHZ at about -55 dBm and no other signals > -120 > dBm. The Tbolt is about 4-5' away from the workbench BUT I disconnected > everything and it is only connected to the TADD-1 distribution amplifier > The TADD has no distribution coaxes attached, it is in the TAPR metal > cabinet which I always thought was well shielded and every port has been > terminated with 50 Ohm dummy load plugs. When I take the TADD-1 out of > the > equation and just run the Tbolt into a 50 ohm termination plug, the 10MHz > signal on my SA drops down to > -90 dBM. I duplicated this with a > Lucent RFTGm-Xo/Rb pair and the TADD-1 with similar results. Has anyone > else seen this with their distribution amp? > > > > Jerry > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
