[time-nuts] GPDSO Distribution amp that does not radiate ?

[Jerry O. Stern]

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