Hi all,
For the first time in probably a long time, I checked several frequencies for
TPs yesterday morning for about an hour (sunrise was about 45 min into the
session).
One of the frequencies I checked was 1566 kHz, and while the signal was often
quickly fading up and down, I definitely heard audio on that frequency. There
is a recording, as well as a few pictures of my PL-606 showing signal readings
(and a small piece of the Select-A-Tenna may be visible) at the link below.
http://cid-6bdd1917662288cb.office.live.com/browse.aspx/AM%20radio%20files/2011-03/TP%20-%202011-03-16
Would it be possible for someone to identify that station upon hearing it?
It's a 2.5 minute recording at about 1342 UTC.
There is some noise in the recording, though, besides what I would expect from
natural atmospheric noise, and I'm not sure if it's powerline noise (they're
probably less than 90 feet or so from where I was), or IBOC hash from 1580 KMIK
Tempe, AZ, which runs 50kW DA-N, the night pattern's main lobe being pointed
almost right at me. KMIK was fairly well audible at the time, but mixing with
50kW co-channel KBLA Santa Monica, and was not nearly as strong as it usually
gets in the evenings. (I've seen it hit 70/25 barefoot sitting on top of my
piano, 80/25 with the SAT, and 91/25 when adding the utility pole ground wire,
making it the strongest station that's usually only received at night here -
only a few locals are stronger.)
Also, I tried for 1575kHz, but couldn't get enough audio for a recording to
post. I did hear the soft-mute on the PL-606 temporarily disengage for a
fraction of a second several times, but never was able to hear enough to be
sure that I was, in fact, hearing a possible TP.
Frequencies I heard hets (but not enough audio to tell if something actually
was there) on include:
657 kHz - sounded like it may have been slightly off frequency
747 kHz - checked this one twice, once before sunrise when KCBS was coming in
on 740, and 760-KFMB was on their 50kW night DA pattern, and once again after
sunrise, when 740 had KBRT (their IBOC was making it very difficult) and 760
KFMB was down to 5kW ND for the day.
774 kHz - also checked twice, before sunset and again after sunset.
Unforutunately, I was getting domestic splatter from adjacents both times. Of
note was the second session - 770-KKOB was pretty much gone by this time
(although I suspect I may have faintly been able to hear them if I tuned the
SAT and pointed it the right direction), so it would have either been coming
from local 760-KFMB (7.3 mi NW) or 780-KKOH, which was audible at the time.
Last October when I got a good signal on 774-JOUB, none of the domestics were
much of a pest (and with the help of the SAT I was able to keep the
blocking/desense from 760-KFMB, on 5kW day pattern, to a manageable level).
I was not able to detect anything on 828 kHz (830-KLAA, which has a fair signal
all day on the barefoot PL-606, was too much of a pest), and I don't remember
if I tried 693 kHz (local 690 XEWW probably would have made that difficult) or
567 kHz (570-KLAC, audible with a fair signal in the daytime, would have made
it difficult).
I did not try for 594-JOAK this morning, either. However, I did log them last
November (Thanks again, Gary DeBock, for confirming it on the yahoo group),
even though I have a local 5kW IBOC station on 600 kHz, KOGO, just 7.7 miles
west of me. :)
About those hets... turns out my dad has a grid dip meter with an oscillator function on
it that can generate low power RF from about 400 kHz to 250 MHz. He got it used at least
40 years ago, it uses a vaccum tube, and is analog tuned, so isn't exactly stable, but I
was able to use it to aid my chase. Basically, first I'd tune it to the desired
frequency, using the PL-606's SNR display to know when I was there, then move it farther
away (if it's close enough I can get 98/25 readings, and have actually briefly seen 99/25
and 06/00 (normal dBu display range is 15-98) once each upon newly tuning a frequency
before refreshing a second later and showing a more "normal" reading) and tune
the SAT, then move it even farther away to further reduce the signal, and detune the gdm
to look for a het. If there was a het, I would turn the gdm's oscillator off and check
that frequency for a TP, occasionally briefly tuning the PL-606 to domestic signals to aid
in positioning the SAT to reduce their strength. If there was not a het, I
would move on to a different frequency.
As for generating a weak signal on/near target frequencies to aid in finding TPs,
does anyone know of an inexpensive (the lower the better even if I have to buy used
- prefer that it be considerably cheaper than the PL-606), portable
(battery-powered& small but doesn't have to be pocket size) device I could
use that would be better suited for uses like that (coverage from at least 150kHz
to 1.8 MHz, up to 22 MHz is a bonus, also strong enough to hit a solid 98/25 on the
PL-606's RSSI/SNR display when within about a foot of it, and an RF gain control
for when I need less power)? Ability to plug in an audio source and transmit that
over short range (maybe a hundred feet - for other testing purposes) would be a
nice bonus, or even modulating the carrier with a tone whose frequency could be set
by the user (when chasing TPs, though, it would only transmit an unmodulated
carrier).
(There's a few other things I wanted to ask about, but this post is getting
longer than I would like (even though it only takes a small portion of the
screen when running full screen at 1920x1440 and browser zoom at about 70%), so
I'll save those for another post sometime.)
73,
Stephen
El Cajon, CA - Grid DM12MS, SE quadrant ; within 1 mi of 32°45'40"N 116°56'50"W
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