[Elecraft] XG1 Builder Report

[William M. Spaulding, Sr.]

Hi, Folks,

For fun, literally, I just built an XG1 "Sig Gen" and measured it's
parameters.

I was using an HP 3585B Synthesized Spectrum Analyzer which has a reference
oscillator oven accurate to within 1 Hz of WWV.  The amplitude accuracy
at -73 dBm levels is better than 1 dB.

Here are the numbers I measured after setting the crystal frequency to
7.040001 MHz were:

S9 (-73dBm, 50 uV) measured at -72.3 dBm, 54.3uV.

1uV accuracy in the 3585 is a little over +/- 1 dB.  I measured 1.12 uV,
which is almost exactly 1 dB high - close for these levels!

Another important parameter I measured was generator output return loss.  I
used a bridge verified to be better than 60 dB return loss into a true 50
ohms.  The XG1 really shines here.  The return loss of the generator output
impedance was flat and 52.2 dB of return loss across the band!  For all
intents and purposes, that's a 1:1 SWR.

It sure is good enough for any but the most demanding measurements for
setting S9.  My K2, no preamp or attenuator measured S9 plus about 6 dB on
the front panel markings.  I think I could fix that.  I'm not overly
motivated to change it

This little kit is fun, useful, pretty darn accurate really compared to many
other sources, and a very good training exercise to get up to speed in kit
building.

Mine's a keeper!

73,

Bill
NA7Y