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Medium Wave AM radio has its faults, but one that should have been fixed by now is the polar directivity of the signal which can discourage listeners needlessly.
Here’s an example. This shelving unit here in the kitchen was custom built for this location… up top is a Panasonic table radio neatly set against the east wall. Some stations come in well, but others would require twisting the radio at a sloppy looking angle so the loop antenna in the back is favoring the north-east.
I happen to know how to swivel, turn and angle radios for best reception, but most people are unaware of it or are opposed to having their radio out of place.
We’ve got to start immediately to design antenna systems that will fill in the nulls and make AM radio optimize no matter which way the radio is pointing.
Engineers have gotten lazy after decades of success and now we stand to lose the AM legacy as stations disappear because radios are facing the wrong way!
No more slacking!
Total posts : 45366The requirement by designers, not necessarily radio engineers, for compact sets without external connections resulted in the use of loopstick antennas which are compact but respond to the magnetic component of the radio signal field. Loopsticks are, as mentioned above, directional.
An aerial, which is just a wire responds to the electrical component of the field and tends to be almost non directional. Even rather short, 1 meter or so, aerials work fine for local reception. The disadvantage is that it is not possible to null out interference such as can be done with the loopsticks.
But, because we just can’t tolerate those ugly wires sticking out of our receivers, we suffer from the effects Carl cited.
Maybe a solution is to use three loopsticks mutually orthogonal in AM receivers with a diversity receiving system.
Neil
Total posts : 45366There were some radios with the ferrite rod outside the cabinet and rotatable so the radio stays in one position and you just turn the antenna. The ferrite rod was in a plastic housing….https://ca.images.search.yahoo.com/search/images;_ylt=A0SO81_2CLBXVgQAb8_rFAx.;_ylu=X3oDMTE0cDhzMmd2BGNvbG8DZ3ExBHBvcwMxBHZ0aWQDQjI1NDZfMQRzZWMDcGl2cw–?p=venturer+radio&fr=yfp-t-620&fr2=piv-web#id=36&iurl=http%3A%2F%2Fpictures2.todocoleccion.net%2Ftc%2F2011%2F03%2F02%2F25089120.jpg&action=click
Total posts : 45366maybe the lipsticks would have to would have to be configured in the shape of a cross or an X Type shape.
Total posts : 45366They put loopstick on a pig and ran it for public office.
Meanwhile, we’re considering criss-crossed lipstick as symbolic of the “New Radio Revolution”.
Total posts : 45366” … Engineers have gotten lazy after decades of success and now we stand to lose the AM legacy as stations disappear because radios are facing the wrong way! No more slacking!”
Most “AM legacy” receivers going back to the Golden Age of Radio 60+ years ago used internally-mounted receive antennas having the same directional receive characteristics as modern-day loopsticks.
Total posts : 45366Regardin: “Most “AM legacy” receivers going back to the Golden Age of Radio 60+ years ago used internally-mounted receive antennas“
What do we know about those pre-ferrite antennas? As I recall they looked like flattened woven baskets.
Total posts : 45366My post stated that those early receive antennas (which were/are another form of a loop antenna) had/have the same directional receiving characteristics as modern-day loopstick antennas.
Your “quote” from my post was incomplete.
Total posts : 45366I know: “Your “quote” from my post was incomplete.”
Because I was only asking about that part of your statement.
Your bracketed remark answers my question: (which were/are another form of a loop antenna).
“Another form” of loop antenna is interesting.
Total posts : 45366Get a radio that has an external antenna input and use an active type antenna.
They are omini directional and have usually a gain to them which would improve
reception range.
Hi Carl been along time since we talked.
Total posts : 45366Yea, my first thought was “Heck, I’ve got radios going back to the 1930’s with wire loop antennas affixed to their back covers”. Same thing, directional, able to peak signal while nulling interference. Been this way since Tesla. The loopstick was the same concept, only smaller to fit in smaller radios without losing as much sensitivity.
I have a couple nice console radios from the 1940’s that have wire loop antennas inside their cabinets inside oval cardboard tubes that are mounted upright in the cabinet and rotate inside the radio. It wasn’t too practical to rotate your 80 pound console radio in the living room, but you could reach behind and spin the antenna.
I have a General Electric “Super Beam-A-Scope” antenna of this style that I rescued from a scrapped console radio. Says right on it “Reduces Radio Interference”. I’ll have to post a photo of it. I saved it from the old radio as it can of course be connected to any radio to improve reception.
Photo later. I’m off to work.
TIB
Total posts : 45366Tim reminded me: “…wire loop antennas inside their cabinets inside oval cardboard tubes that are mounted upright in the cabinet and rotate inside the radio.”
Yes, I’d almost forgotten the big cardboard tube in the lower rear of the radio… as a kid it was a curious but mysterious fixture right near where I learned never to touch wires connected to the electro-magnetic speaker!
Total posts : 45366Just think if we can get the FCC to crack down on these faulty AM recrivers what happens to part 15 Hobby Radio? Increased range. Isn’t that what The New Radio Revolution wants? Why not make this a part of the petition as well no?
Total posts : 45366While I don’t disagree with your intent. I would not include that as part of the petition. I would remain focussed on one area, succeed there, and move to another.
Trying to achieve greater coverage via Part 15 will be hard enough to accomplish without having to defend or justify to radio manufacturers why they should have to cater to what they are being to told is a dying band/mode. That is supposing that the FCC accepts the proposal and it makes it to the stage of requesting comments from the public.
Then add to that, the group petitioning for change are Part 15 Hobbyists?
my .02
Total posts : 45366CraigF is absolutely right about that… stick with one main objective in the “Petition” and aim all the effort toward that one subject.
Here is an additional thought ….
To get radios improved you don’t need to talk to the fcc… speak straight to the radio manufacturers! They don’t need FCC permission to improve antennas or other changes you might want… If they think you have a good suggestion they can go ahead and design better radios! The key point would be whether the public would purchase the new radios.
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