Has anyone else noticed dead spots inside their property while listening to their AM signal doing work in the yard etc.
Here is what i am getting at.
I was using my trusty AM/FM/WB Sony Walkman and a set of over the ear headphones to listen to Blue Bucket Radio 1620 while mowing the yard.
I could have fired up the FM transmitter just to listen while working in the yard but i wanted to see how the AM would hold up while i moved around the yard.
It didn’t do so well, in fact it would fade out to the point where i could hear the mower louder than the radio, then it would pop back into the receiver nice and strong.
My impression is that the antenna being in an L shape is only really radiating off of the shorter more vertical section of wire, the horizontal section which is made up of more than half the legnth of the antenna is wasting power on a horizontal plane.
Our receivers have horizontal bar antennas inside the radio, if i moved a lot while pushing the mower or just walking around the yard the signal would come and go because of a null produced by changing the antenna’s orientation to the transmitted signal. Sometimes i was in the vertical plane, other times in the horizontal plane which would yield very little signal or not enough to provide a listenable reception.
I was also able to rule out the cable line running the length of the yard as a carrier current since no matter where i was, be it under the cable in the air or one either side, the tv/internet cable would not increase the signal strength, so if my cable is re-radiating any of BBR’s 1620 signal then it isn’t as much as i had hoped it would be.
It should be noted that we have more side yard than we do back yard, in fact it only takes 20 minutes to mow the back yard and 2 hours with breaks for water to mow the rest of our yard. That side yard is in direct line with the studio where the AMT3000 transmitter is running.
Looks as though i need to place the transmitter on the floor and run the antenna up the wall facing the yard rather than havng the tx sitting on the desk and the antenna in a bent or L shape.
On the upside, I have had the TH 5.0 on 540 khz re-transmitting NOAA weather radio, that antenna is wrapped around the cable line coming into the house, that signal actually gets out pretty well. It covers the same distance as the AMT3000
(remember my coverage map on the post Unintended Carrier Current?).
Drop Out
With my radio tuned to my AM station and as I wander (and wonder) about my estate I do experience fading but this appears more due to the orientation of the radio than the distance from the house. The loopstick in my receiver makes it directional and I also observe this fading on weaker stations as I rotate the receiver.
Neil
L-Shaped AM Antennas
I have a poor impression of short L-shaped antennas on AM…
You can tune them up from the transmitter perspective, but I tend to suspect that the horizonatl portion of the radiated signal causes some cancelation of the vertical portion.
Also take into account that if the horizontal part of your AM antenna is creating a horizontally radiated plane, it is directional on the perpendicular sides only and nulled at the ends of the wire.
Punch holes in the ceiling or floor or wherever to get a vertical antenna.
Ferrite Core
These AM antennas in radio’s have been around for years and are the most effective way to put a large antenna in a compact radio case. They are directional however.
One can rotate their AM Receiver to null out stations they don’t want to hear.
About Spotty Coverage
Using a TECSUN PL-310 Portable with its digital field strength readings I have mapped out my entire yard so that I can see on one sheet of paper how spotty the reception is and where the strongs spots are.
That is one great way to create a home-made picture of what an antenna is doing.
You could do something similar with an S-meter on some radios.
My spectrum analyzer takes a boat-load of D-batteries but if I ever want to spend the $$$ it will do spectrum readings around the property.
I would..but
Carl Wrote: Punch holes in the ceiling or floor or wherever to get a vertical antenna.
We rent this house and it’s already in bad shape as it is. Our landlord makes a better friend than a landlord. I have already put enough of my own $ into this hellhole and would be afraid that the ceiling would cave in on me lol.
I hate to admit this, but if we could afford to move yet again, i would have already put the wheels in motion.
Chief Engineer
This looks like a job for Frank S. Fuseisbloan, Chief Engineer of Blue Bucket Radio 1620.
Now I just need to get him to wake up, he lives in the closet under the stairs and sleeps all day and half the night. Can’t understand a word he say’s but he always had some mighty fine wine. eermm okay that was Jeremiah Bullfrog… nevermind.
Barry of Blue Bucket Radio 1620
Secret Stash
There is enough room inside the blue bucket for 1 loading coil and 1 bottle of wine.
Normal
Way back when I used to carry a radio around with me where ever I went listening to the hit parade on AM stations in Toronto or out at the cottage and always found that signal strength was not equal everywhere….even up and down a street. Seemed to always be “pockets” of stronger and weaker signal areas. In the car the same thing happens. With a weak station I could receive at my house for example, at the house across the street it may not be receiveable.
Mark
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