Mostly the signal at AM 1680 goes a few hundred feet, getting weaker on the uphill grade, and by the top of the hill is gone. But the radio was left on and there was powerline buzz alternating with a station way off in Michigan, until at about two miles while crossing a 5-way intersection the signal from home was there with enough strength to recognize the program! But in order to keep listening, it would have been necessary to remain stopped in the middle of the cross streets.
Little Surprise
From the accepted theory of radio propagation, this is impossible. From actual experience, these things do indeed happen. So what does that say about all the formal theory? The scientists will fluff this off as an anomaly. We all know there are anomalies. 🙂
Anomalies or legitimate outcomes?
I have mentioned in the past that I have had similar experiences but rather than anomalies I find myself hoping these are predictable outcomes from the accepted theory of radio propagation in environments we haven’t explored. Perhaps there is a water or sewer line that is helping the ground wave right in the middle of that intersection.
I was able to pull my station in clear as a bell for over two miles as long as followed a certain road that followed a certain drainage ditch that was connected to a mitigation pond that was behind the apartment I was set up in that was close to where my 8′ ground rod was located – as long as it was raining 🙂
Both Ideas
I like the mystique of an anomaly because it suggests there are new things yet to be discovered by us, the Part 15 inventors.
But the sewer line explanation also opens new potential that would be similar to carrier current. We would have sewage current radio, a whole new concept.
Anomalies
“We would have sewage current radio, a whole new concept.”
That’s already being done on many stations, at least in terms of programming.
Sorry, couldn’t resist.
All “anomalies” can be explained by current theory, the mystery appears because we can’t predict them in many cases but we can explain them after the fact. Carl’s experience could have been due to power lines. I have noted that they act as passive repeaters even for stations many hundreds of miles distant.
Ham radio low bands are much like this. Propagation is predictable but, as with the weather, it changes quickly at times. Two nights ago FL and TX stations were booming in here and last night no FL or TX but lots of East Coast signals were strong.
Neil
The Magic of It
Neil, your comment about programming still has me laughing so please wait ten minutes while I calm down.
What’s good here with the anomalies and the electric line repeating that may be going on is the seemingly magic notion that our small stations might reach DXers way out somewhere.
I’ll take my comments off the air.
Part 15 “DX” in 1969 3000 Feet
First of all, you guys are making me laugh
too hard.
In 1969, my Part 15 AM station, WBVR, which
stood for Buena Vista Radio (because the Buena
Vista Golf course was across the street), was
operating, sort of. The transmitter was a
Lafayette KT-195 tube kit. There was also a
built version that cost more, and this transmitter’s
history has been covered here. (The built transmitter
was the KA-320, I believe.) One wonderful experimenter
on this board got that transmitter and made it a lot
better, and my hat’s off to him. I think it was MRAM,
but I’m not sure. The memory is too far back in my
brain.
Anyway, WBVR AM was a mess in many ways. The
test receiver was from a store called Korvettes.
(Anybody remember Korvettes?) The receiver got
AM/FM, 1.6 – 4 MHz (the Marine band) and 4 – 12 MHz.
The Korvettes portable was full of images.
I wanted to be on 1600 kHz. In my mind, the higher
the frequency, the better. But it didn’t matter to
me that there was already a station on 1600 just
25 miles away, and it was audible in West Hartford!
Later, the channel of choice was 1460. It was pretty
clear during the day. But try as I might, it was not
to be. The transmitter had problems and the receiver
had bad image rejection. When I tuned the receiver
to listen to WBVR, it was on frequencies all over the
AM dial and beyond. None of these transmissions left
my yard. I had no idea if I was transmitting anywhere.
And I didn’t know what channel I was really on, if
any.
One day, I was trying to get the KT-195 to go
somewhere. After giving up, I was transmitting
records through it. The transmitting antenna was
a 10 foot piece of 300 ohm twin lead just hanging
down off the back of the table onto the rec room floor.
I think only one side of the twin lead was actually
connected to the transmitter. And this set-up was
in the basement of my parent’s house, underground.
3000 feet away, on the other side of the golf course,
across a pond, my best friend was tuning around on
a Knight Kit R-100A receiver attached to a 90 foot
long wire outside antenna. Somewhere around
2100 kHz, he heard a bunch of phonograph records
being played with long pauses of dead air in between.
After a while we talked and figured out that he was
hearing my transmitter! 2100 kHz? What was I
doing up there? And it was S6 on the R-100A’s
signal strength meter. Well, try as we might we
could never get the KT-195 to go anywhere on
the AM BCB. Nobody in the neighborhood could
tune 2100 kHz except my friend. Since the
transmitter was AC/DC and I was always getting
shocks from it, the KT-195 was abandoned and
WBVR went to FM. (That’s another story.)
Today, my friend and I still don’t understand how
he could have heard my transmitter 3000 feet
away with just a 10 foot transmitting antenna on the floor
in the cellar! To this day, we are still calling it “The BVR effect.”
Although we have a lot of theories how it might have
occurred, the actual answer is still a mystery.
Best Wishes,
Bruce, MICRO1690/1700
Images and Other Speculation
Bruce, it is fun to speculate but as you said you will never know for sure why this happened. My guess is that you had actually tuned the tx. to 2100 and thought you were on 1600 because you were hearing an image on your receiver. This happened to me a lot when I used home made LC tuned FM txs.
As a kid with not a lot of discretionary income I sought a good receiver just to listen to rock and roll on AM and my part 15 station. I had a nice Crosley tombstone radio but it didn’t put out the volume I wanted and it wasn’t very sensitive (when I learned to align receivers this problem was solved). I had read that car radios were good receivers with lots of audio power so for a few bucks and some wrench time I obtained a Buick 6 volt car radio from a local junk yard. A salvaged power transformer from a junk TV I found in the dump provided 6.3 volts at a few amps. The radio had a vibrator to convert the usual DC in into AC to power the tube rig but this was not needed since my source was AC. I removed the vibrator and strapped across the connections so the 6.3 VAC went directly to the step-up transformer. I also replaced the miserable 0Z4 rectifier tube with diodes. For a speaker I used a 12″ speaker in a gutted TV cabinet. This worked great with a short whip antenna. The polish was I added a DM70 fluorescent indicator tube connected to the volume pot hot as a tuning and modulation indicator.
I still have the radio and transformer but the last time I fired it up it didn’t play. Something is dead in the IF and though it would be great to hear it once again it remains stored at low priority for a fix.
As did you, I learned that a good receiver is necessary if you are going to do any serious hobby broadcasting and crystal controlled transmitters are a blessing.
Neil
Car Radios and 1160 kHz
I have enjoyed all your posts.
One question to you, Neil, how old
were you when you took that AM
car radio out of the junk yard and
made it into a real “in shack” DX radio?
Even when I received my Novice ham
license in 1971, at age 16, I did not
have that kind of practical knowledge.
Also, I have a vivid memory of listening
to KSL, 1160 kHz, Salt Lake City at night
on the car radio in Rhode Island. Of
course, the car radio was IN the car.
This was when 1160 was empty at night.
WJJD 1160 (country music) would sign
off at sunset from Chicago. I heard THAT
station many times in Connecticut.
As many of us remember, there is a Part
15 experimenter who revived WJJD on
his own, which I think is really cool. And
I think he put his Part 15 AM transmitter
on 1160.
Anyway, best wishes to all.
Bruce, MICRO1690/1700