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Old March 2nd 10, 02:37 AM posted to rec.radio.shortwave
bpnjensen bpnjensen is offline
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First recorded activity by RadioBanter: Jul 2006
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Default Been listening to KDKA AM radio in digital

On Mar 1, 6:04*pm, Bob Dobbs wrote:
bpnjensen wrote:

I have 50 kW KGO 810 about 5 miles away, grounded in the same SF Bay
mud as my own ground.


It almost pins my S-meter at minimum 40-over even attenuated, and it
takes a massive effort to hear anything 10 kHz away from it;


During the day when KGO runs IBOC you've got those twelve and a half kc
sidebands to plug your reception on either side (800/820).

my
MFJ-1026 works totally overtime to crush the signal even when I use
USB/LSB on narrow and passband.


If your canceler is having trouble trying to null something,
about the only recourse is to reorient your sense antenna.

Even worse is another 50 kW blowtorch
just 1.5 miles away on 1100 - yecch! *Not only that, but its harmonics
are potent on 2200 and 3300 (farewell, R. Cultural, Guatemala). *I
wonder if the 1026 can wipe that 3300 harmonic...


That's another whole different issue;
is it the station that is radiating harmonics,
or some inadequacy in your receiver?

--

Operator Bob
Echo Charlie 42


To answer both your and Brenda's questions - I have an Alpha-Delta DX
UItra Multiband dipole and a 50-foot inverted L up about 20 feet.

Obviously, these two antennas will not be a perfect match for all
kinds of noise or nulling a superpower radio station a mere 5 miles
away. However, they do a respectable job - I can kill a lot of noise
with the 1026, and believe me, I have a TON of it. I can make most
local AM stations nearly inaudible with this set up - but KGO and the
thing on 1100 are just too potent. I receive them powerfully with *no
antenna at all* attached. It is hard to overstate the signal of these
monsters at this location. There are two others at 1050 and 1550 that
come close, also both a stone's throw from here.

I am aware of the rectification potential of poor solder joints and
dissimilar metals. It is entirely possible that I have one or both of
these problems after having these antennas up for a decade or so. It
has always been thus, though, and even when I attach a simple wire
directly to the Hi-Z input of my R75. FWIW, only 1100 seems to have
this effect very strongly, and it is better than it used to be (I used
to get it on 4400, 5500 and occasionally 7700).

Bruce