[SJDXA] Stew Perry Overview de W2GD

[Bob Schenck N2OO]

Good Morning....
 
Its the day after the Stew, and following several 'naps'  yesterday
afternoon and evening maybe I've finally caught up on my sleep.  
 

I'll summarize the Stew experience as just "OK".  Activity was noticeably
down, conditions were best at the beginning (around sunset) and went down
hill significantly from then on.  Our best EU runs were in the first two
hours.  Condx to the west were somewhat better than during the ARRL 160 but
not that much better, at least they heard us most of the time when we
called.  Overall we did OK, our QSO total is down 15% compared to last
year....and so is our total score.  We were light on operators, that was
probably one of the factors, and we didn't push realhard either.  Since we
went into this as a 'tuneup' the score is no big deal since we identified a
few additional improvement areas to explore over the next six weeks leading
up to the CQ160 CW.

 

 

What Went Well (as discussed by K2TW, N2OO and W2GD at breakfast Sunday
Morning)

 

There now seems to be no doubt raising the TX array about 60 feet has
improved our signal in both NE and West directions.  Not a scientific
observation, more antidotal, but none the less we feel LOUD, therefore we
are loud.  Several EU stations in their TBDC 3830 soapbox comments mention
our being a beacon signal, a sign we probably have one of the standout
signals over there.  And this is backed up by our ability to attract an EU
pileup and get through quickly when calling stations from the mult position.


 

On Friday, Rick, K2XT and I moved the bottom half of the NE driven element
about 20 feet further away from the bottom leg of the delta loop by
extending the coax and pulling the NE center support rope taught.  On
Saturday TW found it did not require retuning.  What was most notable though
was a change in how the system performed in OMNI mode, the SWR curve was
significantly broader as you went higher in the band.  As N2AA says "LOUD IS
GOOD" and the TX antenna seems to be delivering.  Its now getting close to
being optimized according to the models.

 

The move this season to using the big TX array at all times (on both the run
and mult positions) is an unqualified success.  So far the new Acom 2S1
switch has worked flawlessly, and Tom's amplifier has proven to be tolerant
of some somewhat extreme frequency excursions.  Calling stations from the
mult position is now much more likely to be successful than in prior years
while using the backup TX antenna.  Bottom line this is a significant
improvement we can capitalize on during the CQ160 CW.

 

A new relocated 565' West beverage strung Friday by K2XT and W2GD was a
standout performer this weekend.   It was exceptionally quiet, and became
the "go to" antenna for anything West...as it should be.  This new west
beverage starts near the SW and NW beverages, which will make running the
feedlines (along a common route) easier in coming years.  We discovered a
bad run of RG8X cable in the conduit behind the bldg, which registered 6dB
loss on an MFJ analyzer...more on that situation later.

 

The NE phased bev. array was hearing very well this weekend as it has since
last season when everything was overhauled by W2NO.  No change there.  The
only questionable beverage this weekend was the SW.  We haven't walked it
yet this year ... it didn't sound as crisp as it did during ARRL 160, so it
probably needs some attention.

 

 

What Didn't Work as Hoped During the Stew

 

K2TW, K2XT and I spent a few hours Saturday working on the relocated short
vertical.  We tested the coax from end to end (all OK) but discovered once
again the small 27 uh mini inductor used to tune the antenna to around 1800
khz had broken and wasn't repairable.  The antenna self resonates at 3500
khz, as expected.  We called Henny, N4HY, and his suggestion as an immediate
fix was  to just bypass the inductor and connect the ~67 ohm resistor which
is in series with the inductor directly to the vertical.  We did this, we
could hear signals, but at the shack end reception was never as good as
we've experienced the past two years with this antenna.  Its still not
right.

 

Since the short vertical was apparently not working correctly, we did not
enjoy the real benefits of 'Diversity' reception on the K3's this weekend.
In retrospect, we could have substituted the backup Inverted L as our
diversity antenna on the sub receivers and probably should have (the
beverages are connected to the main K3 RX).  I estimate it cost us about 40
qsos with weak signals.

 

While Tom was on the run station with N2OO's K3, and I operated the Mult
station using K9RS's loaner K3, we compared them and found not all K3s are
created equal.  You could hear a significant difference in noise levels and
station readability as a result.  Not sure what all this means.  Possibly
its the difference in filters....the OO radio only has two roofing filters,
the RS radio may have more.  Anyway, this is a subject for discussion and
some additional testing before CQ160 CW.  

 

The only other significant issue I can recall was the loss of internet
connectivity twice.  For some reason the wireless modem stopped seeing the
DSL connection.  The fix was to remove power from the modem so it would
reboot, then restart the instances of Telnet we had running.  In both cases
this fix worked fine.  

 

 

TO DO Items before CQ160 CW on Friday January 27th, 2012

 

1.  Walk the SW beverage and check for downed trees, etc.  Consider
restringing the SW beverage element completely using one of the 'spare' west
elements still in place (we had a 560' two wire echelon bev. array West at
one point - I want to keep the old West element for a possible EAST beverage
in the future).  Also check the SW feedline for bad connections and possible
losees.  IN PARTICULAR, check the RG8X feedline that runs into the building
through the conduit behind the building for loss.  

 

2.  Replace the 27 uh mini inductor in the short vertical tuning box (I will
obtain the replacement inductor)  and retest antenna.  If results are judged
unsatisfactory, consider repositioning the vertical 1000' closer to the
building to eliminate one of the 1000' RG6 runs in the system.  With skimmer
spots now readily available on the cluster, the need for an RX antenna that
attenuates our TX signal is not as important as it was previously.  Another
alternative is to throw up a temporary Inverted L RX antenna somewhere 1000'
from the the bldg. and use that in lieu of the short vertical as our omni
directional  'diversity' rx antena.  There are many tall pine trees
available in relatively clear areas in the woods to install such an antenna
to the west of the stn.  Just one or two ground radials would be required.

 

2a.  IN THE SHACK, install a multi position coax switch in the K3 sub rx
line to allow access to the short vertical and some other omni directional
antenna (like the backup Inverted L).

 

3. We have not checked the resonant frequency of the Delta loop reflector
for many years, and it is the last potential tweak we can make to the TX
array to increase gain.  To really KNOW what we have out there, we should
make the effort to do this measurement and if necessary an adjustment.
Given the size of this element, the potential for wire stretch over time is
compelling reason to do the test.   

 

Drop the ends of the big loop, install a permanent insulator at the current
break point  (e.g. an Alpha Delta Center Insulator - we have spares) to
provide an SO239 connection in the center of the bottom leg.  Reinstall the
loop with the bottom leg unshorted and a ~100'
 RG8x line connected.  Measure the resonant frequency of the loop (this may
require taking WYRS off the air for a few minutes to do measurements with an
MFJ Analyzer  in the field since the RF field in the vicinity of the tower
swamps the instruments).   If the loop is NOT resonant in close vicinity to
1815 khz, adjust  the length of bottom leg as required to achieve the
desired resonance near 1815 khz.  Once tuned, reinstall loop with the bottom
leg shorted and RG8X coax removed.  RECHECK SWR curves of NE and WSW driven
elements, and adjust  their length as necessary to have the desired SWR
curves.

 

4.  Test all of the RG8X cables in the conduits at both ends of the building
for loss.  Consider replacements which use no-contaminating buryable
material, like RF Davis Buryflex RG9913F7 or something equivalent.  We've
had nothing but trouble with these cables with crimp connectors
supplied/installed by NO2R many years ago (one of those cases where being
frugal has come back to bite us...repeatedly).

 

 

OK, that's the report on current status.  Have a great Holiday season and
see you in 2012.

 

73,

 

John W2GD

 

 

 

See ya' in the Pileups!

73!

Bob Schenck, N2OO

President SJDXA

GO SJDXA!!! www.sjdxa.org

 

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