Greg Wrote:
Hi Gang:
Need help insetting up the TCXO 1ppm oscillator.
I was trying to get Method 3 to work in setting up the oscillator.
I can get to the menu CONFIG:REF CAL but when I tap 1 I do not get EWF
xxC. I assume tap 1 is the #1 key on the key pad? Any help will be great.
Ed
WA3BZT
Ed,
Please review your errata sheet that came with the radio. The firmware
is not yet ready for this calibration method.
For the record, here is another method for anyone who has an accurate
10MHz frequency standard and an oscilloscope with X-Y inputs.
1. Set up the 'scope to display a Lissajous pattern in its X-Y mode,
with sampled RF at 50MHz into the Y input and your 10MHz standard into
the X input.
2. Set the K3 to 50.000000MHz CW. Key down. You should see a slowly
rotating 5:1 Lissajous pattern.
(The pattern looks something like
http://www.math.com/students/wonders/lissajous/lissajous.html
with the following user settings:
xFreq = 10 000
yFreq = 50 001
hue Freq - any setting
Samples = 500 or more.
In this simulation, the offset between xFreq and yFreq gives a pattern
that goes through one complete evolution in about 20 seconds. Click
yFreq down to 50 000 to freeze the pattern at its current phase
difference; this corresponds to 'zero beat' between the two
frequencies.)
3. Use the VFO A knob to 'tune' the CONFIG: REF CAL setting until the
Lissajous pattern is rotating as slowly as possible. Using this visual
method you should be able to zero-beat the two frequencies much more
accurately than by ear (Method 1). The practical limitation is the 1Hz
granularity in REF CAL settings.
--
73 from Ian GM3SEK
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