[NLRS] 10 Ghz Baby Break....

[Mike King - KM0T]

Hi all,

Just wanted to report that the prop was not too bad this early morning.
Colleen was still in the hospital this morning and I took a bit of time off
to meet Jim, K0KFC and Donn WA2VOI on 10 ghz this morning.  (I also heard
W8MIL on 2M this morning, about 5x5 ssb with qsb.)

Jim got the schedule set up with me for 7:00 am and went out to Flying Cloud
airport, En34gt.  Donn came along too, even with it being early in the
morning :)

First transmit sequence here did not produce anything, however we found each
other the next round and all managed to work each other on CW.  Apparently I
was very strong there, 559 to qsb fades to the noise.  Donn and Jim were 529
to in the noise with qsb.  A little peaking on this end got them up to 4x1
to 5x1 SSB.  SSB there from me was very good as well.  However I was hearing
them (barely) 3 to 5 degrees off of each side of the main beam heading, so
it seems that folks will be fairly ok to find if they are in there.

It was pretty exciting to hear those 10 Ghz signals come thru from 180 miles
out!  It doubled my best DX on the band and they gave me grid number 6 on
the band.  Donn was tickling the S-Meter for a bit as it seemed to peak up a
bit and actually showed up on the 756 ProII bandscope.

Intresting to experiece the drifting, an issue that we will have to deal
with apparently.  Ambient temperture sure starts my freq out at different
places.  Jim indicated that I was quite a bit away from the freq that I was
at a week ago when he heard me.  The temperture was probably 15 to 20
degrees cooler here this morning than the other time.

Gene, N0DQS and I noticed the same thing when he went grid hopping some days
ago.  When it was really hot, we found each other around .103.  We tried it
one night after that when it was cool, we were around .090.  We also noticed
that as we chatted, we had to follow each other.  Going back and forth for
about 5 minutes resulted in about 3 to 5 kc drift.

This morning, I noticed about 2 to 3 kc drift as we were going back and
forth.

I dont know if it is just me, or all of us, but it does seem excessive
although not impossible.

One thought is that with my setup, the amp is also in the same enclosure and
produces some heat.  The 13 watt amps draw about 5 amps, so there is some
definte heat, but it seemed that it should take longer to take affect.

Another thought could be my IF setup.  I am using a 756proII at 28Mhz and
that drives a SSB 2 Meter transverter.  Combinations of both of these
drifting a few hertz I would imagine contribute to the drift.

I did some reserch on the web and lots of the guys in the UK that are using
the DB6NT product as I am are also experiencing drifting as well.  Seems
most die hards have gone to an external OCXO and insulated that box with
foam, etc.

I wonder if the whole transverter assembly could be insulated, some thin
foam material or similar.  I wonder if this would be an intermediate
solution.  However I will have to see if that is an issue for the
transverter itself since the whole assembly gets pretty hot from its own
internal crystal heating element.

Now this will probably not be too much of a problem when sigs are good, but
the weak ones could get missed as they move out of the passband during qsb
swings, etc.  Just have to deal with it for now I guess and see how it goes.
If it blows alot of qsos, then I will probably look into it a bit more.

For now, I will need to be aware.  Does anyone have experience with these
OCXO devices?  The DB6NT transverter schematic indicates how one can connect
one pretty simply.  It requires 106.5 Mhz at 1mW.

One other thing I think I will try is go with a FT-100D at 144 Mhz to drive
it all, that way I can eliminate one part of the IF chain and see if that
cures the drifting.  If the IFs are drifting, I would imagine an external
occilator like a OCXO will not make a difference.  Any comments or
suggestions?

Reguardless, it was an exciting event working both Jim and Donn from down
here!

73

Mike- KM0T