[IRCA] New logbook started and new antennas tested

[Tim Hills <thills@xxxxxxxxxxxxx>]

After losing all my old logs and equipment in a fire I gave the hobby up 
for a while but I'm starting over.

I have been working on 2 different approaches for antennas to handle the 
RF zoo I live in.

One is a dual spiral, 10 turns total and 30" diameter in 2 layers 1" 
apart with varactor tuning and a single turn pickup loop.
The other is an 11" ferrite rod made from 2 5 1/2" rods from same model 
Panasonic thrift store radios also with varactor tuning and a low noise 
preamp. 102 turns of wire center tapped for the resonant winding and a 
12 turn pickup coil. Several trial winding schemes were tried with #30 
solid before I made the final with the Litz.
Both are wound with 40/44 Litz. Both have their advantages. The dual 
spiral is very sensitive for it's size but more prone to off channel 
splatter and local QRM and it seems to do better below 650KHz than the 
rod. Because there's 2 spirals working together the null is along the 
axis of the windings and sharper than the traditional coil or spiral.
The active rod's only real disadvantage is the touchy tuning but it 
covers from 500KHz to 1900KHz, 2MHz if I push the voltage over spec on 
the varactors. Neither antenna has shown any sign of intermod or 
overload but I do have to reduce the gain on stronger signals with the 
active rod. I'm also working on a LW version of the active rod using the 
7 1/2" rod salvaged from an S350DL. That POS is more useful in my 
junkbox than on the bench.

The last 4 entries made in the wee hours show that my efforts have been 
worth it. KXRB is 100W Directional aimed right at this location and just 
over 4 miles from here.

Receiver, DX-440 slightly tweaked. Added shielding.
Antenna used for these was the active rod.
All times are UTC.

990 CBW, Winnipeg, MB. CBC news with ID at 10:13 and "Weekend Morning 
Show" following. This one came in clear with a few lightning crashes but 
no interference from KXRB. CBW runs 46K at night but I'm on the back of 
the pattern
1000 KXRB Sioux Falls, SD, Local CW station with ID at 10:18
1000 UNID OM with Southern/Texas accent talking. Not clear enough to get 
any ID but nulling KXRB enough to get anything was a surprise to me.
1010 KCPW Salt Lake City, UT YL with British accent discussing "Female 
mutilation" with guest. BBC World Service 24/7. 11:30 ID
Imagine my surprise at hearing a YL with a Brit accent when I tuned to 1010.
Radiolocator still lists 1010 as a religious station but according to 
the article at Radio Netherlands Worldwide 
<http://blogs.rnw.nl/medianetwork/bbc-world-service-to-be-available-247-on-am-in-salt-lake-city> 
KCPW is only running 194W at night and it's over 800 miles away! Maybe 
after a nap I'll have to do some inverse square calculations...
There was some splatter from KXRB but tuning the radio to 1011 and 
tweaking the tuning on the rod eliminated most of it.

Tonight I'll see how it does with the 5KW directionals aimed at my back 
yard....
_______________________________________________
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