[XG3} Experiences and Opinions?

[Bob Molloy]

Hi,

 

As I slowly expand my knowledge in homebrewing, I've decided an XG3 should
be my next piece of test equipment (after a DMM and a Rigol DS1102E 'scope).
My main interest in the XG3 is for receiver alignment and RF tracing.

 

I'd like to know people's opinions and experiences with this generator.

 

Thanks & 73,

Bob  KD2UJ

 

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[Don Wilhelm-4]

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

On 9/13/2012 8:13 AM, Bob Molloy wrote:

> Hi,
>
>
> As I slowly expand my knowledge in homebrewing, I've decided an XG3 should
> be my next piece of test equipment (after a DMM and a Rigol DS1102E 'scope).
> My main interest in the XG3 is for receiver alignment and RF tracing.
>
> I'd like to know people's opinions and experiences with this generator.
>
> Thanks & 73,
>
> Bob  KD2UJ
>
>

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[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

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