[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[IRCA] Unterminated, Phased BoG test (10/11-12)
After finding a suitable DX site, I measured out the 2 wire antennas: one
antenna being 300 feet long and the other one 160 feet long. Both are made
from 20 AWG, stranded, aluminum (or tinned copper). I measured both antennas
against the curb of an isolated dead-end street. Each cement piece of the
curb was exactly 10 feet long which made a handy reference. Next, I went to
Ace Hardware (conveniently a block away) and bought a 4-foot dowel for the
newly-loaded spools of antenna wire. Electrical tape was placed on the dowel
2 feet apart (to keep the spools apart) since the antennas would need to be
separated by at least that much.
For a phasing method, I brought along a Quantum Phaser, powered by 8 D-cell
batteries. Since the Quantum Phaser needs PL259 connectors, I used the PL259
connectors that were attached to small sections of RG-8X coax. After
stripping away the shielding, making sure it was out of the way, I connected
the antennas directly to the center wire. There was no impedance matching
used.
At the DX site (cold and raining pretty good by now...argh!!), I began
reeling out the wire. In order to keep both spools from falling off the ends
of the dowels, had to hold the ends. Maybe in the future, using a metal
dowel with cotter pins would make more sense. The BoG antennas were oriented
NE.
DXing began around 0110 UTC. I immedately noticed signal strengths were
weak, similar to my flag antenna at home, likely due to impedance
mismatching. 890-WLS was about S-5, but stations off the SE side were nearly
S9, like 740-KRMG, 1080-KRLD, and 1170-KFAQ. Off the back of the antenna
(SW) were Denver locals (S9+20 in some cases). I immediately set out to
phase some of them, like 850-KOA. I was able to knock out all local
stations, but phase-nulls were touchy and left little co-channel signal
(like S-1), maybe good enough to pull out an ID. One of the more noteworthy
phase-nulls was 910-KPOF, leaving a station in Spanish.
While the back end was nulled, pickup off the sides of the antenna was still
OK. The phase-null of local 950-KRWZ produced a weak Radio Reloj (Cuba), for
example. And, while the sides were nulled, pickup off the back was still
possible. The best example was a phase-null of 1080-KRLD and logging XEDY
with a clear S-2 signal. While this is easily done with a tuned indoor loop,
it's noteworthy that side nulls were much less touchy than nulling off the
back.
Reception off the right side (SE) was great! The Cuban Reloj was noted on
570, 790, 820, 930, and 950. There were many stations heard carrying LSU
sports. Stations off the front were weak (this may also have been caused by
the A-index hovering around 25). 1030-KTWO was strong most of the evening,
but co-channel XESDD was pretty strong at times off the back. I also noted
660-KTNN, 690-XERG, KGGF; 980-KFWB, 1130-CKWX, 1140-CHRB, 1160-KSL (strong).
There were no TA carriers like I get from home on a 6 ft x 6 ft broadband
loop. Again, that could be caused by the A-index at 25. Cold rain and a high
index...could the timing of these events be any worse?
Unid, but interesting receptions were on 1110 (station with LSU sports under
KFAB), 1540 (sports station under KXEL), 900 (U.S. station in English), 1040
(unID SS "Radio Vida Abundante" - likely KCBR?).
Conclusion: Although the (unterminated) BoG antenna system was oriented NE,
the best reception was from the SE (side). Receptions to the SW (back) and
NW (side) were good. Reception to the NE was dismal which was unexpected and
perhaps due to the high A-index. However, CKWX and CHRB to the NW (side)
were dominant.
After 2 hours of listening, I powered down the Drake R8 and Quantum phaser,
wound up both antennas and sloshed back to the car.
73.
Chris Knight
Fort Lupton, Colorado
http://sites.google.com/site/2008amloggings/
_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca
Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers
For more information: http://www.ircaonline.org
To Post a message: irca@xxxxxxxxxxxxxxxx