[Elecraft] [XG3} Experiences and Opinions?

[Edward R Cole]

Bob,

The XG3 is quite a capable signal generator.  It can do a lot,
especially when used with the XG3 Utility program, and sounds like it
would be excellent for the purposes you have stated.  It is quite stable
both frequency wise and output level wise.

Drawbacks of the XG3 as I see it is that one cannot simply add an
attenuator to obtain extremely low signal levels (for true MDS
measurements), the XG3 is not shielded.  The only other downside is that
it has a square wave output.  That is not normally a problem because you
would inject the signal into the tuned circuits of a receiver front end,
and those tuned circuits turn the waveform into a nice sine wave.

73,
Don W3FPR
------------
Bob and Don,

I use my XG3 frequently and mostly to check health of my receivers on 
freq up to 1296.  Above 200-MHz the output is a harmonic so output is 
not calibrated.  I think typically output follows (1/n)^2 rule 
(inverse square of harmonic multiplier)  e,g, 432 is -9 dB since XG3 
runs at 144 and uses 3rd harmonic.

On freq. up thru 200-MHz I find 0 dBm level calib is within 1-dB as 
measured on my HP microwave power meter.  Checking -33 and -73 test 
levels against 0 dBm into attenuators is very close.  -107 dBm 
suffers some leakage so use of a shielded enclosure is needed (I use 
a Hammond 1550 diecast box with BNC bulkhead adapter).  With use of 
the box I can add attenuation down to about -145 dBm with no 
leakage.  If I use double-shielded coax I can go to -155 dBm

That is eme quality receiver sensitivity on 144.

I have even used my XG3 for testing VHF transverters by running 0 dBm 
at 28-MHz into the transverter in place of IF radio drive.

Square wave doesn't present a problem for most testing.  Total power 
out of XG3 >200-MHz is the fundamental plus harmonics so may be an 
issue if tuning circuits that can pass both frequencies.  I bought 
several 7-pole LP filters from CoilCraft to filter all harmonics of 
the suqare wave when a pure sine wave is needed.

Only shortcoming is testing FM radios as there is no provision for 
modulating the carrier signal.  But you can observe quieting of the 
FM radio with a test signal.

73, Ed - KL7uW