Hi dear topbanders, I need your help please.
I am a little confused about my result experiences in
my fight against the noise and I will highly
appreciate your thoughts to enlighten me.
Loop description:
I built 2 loops, all with RG58, diamond style, 5ft
each side (20 total).
Loop 1 only the braid used, capacitor on top corner,
large snap core with 9 turn secondary down corner. It
gave 1:1 SWR in an Autek.
Loop 2, shielded style, braid open at top, cap between
inner conductors down corner while braid
uninterrupted. Coupling: RG58 loop about 1/5 dia,
braid open on top and then the end of the right braid
connected to the beginning of coupling loop braid.
Results so far:
Loop 2 performed a little better than 1. On both,
signals are nearly 30db down the TX antenna, compared
with 15/20 db which I read in most places.
Now what confused me and is driving me crazy, I always
read that users get at least some improvement in S/N
and many much more over the transmitting antenna,
which in my case is an Inverted V for 160.
Loops used inside are completely useless. At the roof
150 ft high it works but under no circumstances
(although sometimes close) could pair or improve the
inverted V S/N. (I tried many times complete
disconnecting/opening the TX antenna with very little
difference, it's apex is at same level but 50/60 ft
away).
I don't use a preamplifier because even at 30db down,
the band noise is above IC751A noise floor.
I tried it on 80 mts during WPX, more output but same
result, It couldn?t outperformed my horizontal TX
antenna S/N.
Last weekend I went to an apartment just in front of
the sea, (400KM from my QTH) 6 floors tall, same
combination Loop 2 and Inverted V sometimes completely
opened. Same result respect S/N even with the inv V
top at only 100 ft.
I need to understand the system, as normally said by
Tom, and what is going on. I must be out of focus with
my attempts or the interpretation of the results.
Future work and please your help here:
My next step will be to try a half or full size
pennant with the transformer suggested in W8JI page,
but I am wondering about this:
On 80 meters my S/N ratio was always better on
horizontal dipoles rather than verticals, inverted V
or full size sloper.
1 - Why the loops are receiving more noise than
distant signals? Could it be a matter of
polarization?2 - could it be possible I need to use
horizontal polarization with the loop? could it be
done simple rotating it 90 degrees?
3 - If I suffer the same symptom from the pennant,
Could it be possible to change it to horizontal
polarization? how?
4 ? Any other idea is welcome
Many thanks in advance dear fellows, and as suggested
by many, I didn't give up. LU2DKT...Edy.-
____________________________________________________________________________________
TV dinner still cooling?
Check out "Tonight's Picks" on Yahoo! TV.
http://tv.yahoo.com/
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|