Hello Chris,
It's really not that big of a deal.
You need a calibrated frequency source, either a frequency counter, or you
can use WWV on 10 Mhz. I find it helps considerably if I use a program with
a frequency waterfall, such as Digipan or MixW, to help me visually align
the unit. If you run PSK31 you are all set as far as the software goes.
Unscrew the top of your rig, but leave the top on. Get your digital
software program turned on. Turn your rig on and let it warm up for a
half-hour. Then, tune the rig to 10 Mhz in CW mode. You should hear, and
see (on the waterfall), a carrier at your CW offset (i.e., 700 Hz). You can
use the 'CW Spot' function (pressing and holding the CW mode button) and it
will put a signal on the waterfall at the exact offset frequency. Your goal
is to get the WWV carrier _exactly_ aligned with your CW sidetone.
The way I do this is to use the tuning knob to get the signals as closely
aligned as I can. This will result in your frequency display being off by
the amount that you need to align it by. Once the two signals are lined up
on the waterfall, I then remove the top of the rig, and adjust either C31 on
the Logic Board (if you are working with an original VI with the crystal
oven... see the manual for location) or the trimmer cap in the TXCO (if you
are working with an upgraded VI or VI+, and your manual will tell you which
one you have) so that the frequency display reads 10 Mhz.
You will need to go thru a few 'tune and align' iterations, where you tune
using the knob to align the signals, then adjust the trimmer cap to bring
the freq readout to the desired settings.
Once you've got 10 Mhz exactly on the display and the carrier/sidetone are
as close as you can get them, switch to USB mode. This should show you the
regular WWV tones (at either 500 Hz or 600 Hz depending...). Note that as
you switch between USB and LSB that the tones should move symmetrically
around 10 Mhz, i.e., -500 Hz offset for LSB, +500 Hz offset for USB. Use
your tuning knob to get the USB/LSB offsets to be as close to symmetrical as
you can, and then use the crystal oven/TXCO trimmer caps to re-set the freq
display to 10 Mhz.
Using this method I'm able to get less than 10 Hz offset... on my rig within
a couple of hertz.
Hope this helps,
- jgc
John Clifford KD7KGX
Heathkit HW-9 WARC/HFT-9/HM-9
Elecraft K2 #1678 /KSB2/KIO2/KBT2/KAT2/KNB2/KAF2/KPA100
Ten-Tec Omni VI/Opt1
Alinco DR-605TQ
Icom T90A
email: kd7kgx@arrl.net
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|