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Author Topic: weak signal reception  (Read 782 times)

Offline pinto vortando

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weak signal reception
« on: July 31, 2018, 2146 UTC »
Been noticing an interesting affect when tuning around on the NDB band.  If a strong local beacon is tuned in, it seems to pull up weaker signals on the same or adjacent channels.  Is there a name for this or is it just my imagination.  ???
Das Radiobunker somewhere in Michigan

Offline Boriken

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Re: weak signal reception
« Reply #1 on: July 31, 2018, 2325 UTC »
Similar to exalted carrier reception with crystal radios. Here's a better explanation than I could do.

http://www.crystalradio.net/crystalsets/bfo/
Scott / WB4YZA
Western North Carolina
Mosty homebrew, 100% analog

Offline pinto vortando

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Re: weak signal reception
« Reply #2 on: August 01, 2018, 1120 UTC »
Similar to exalted carrier reception with crystal radios. Here's a better explanation than I could do.

http://www.crystalradio.net/crystalsets/bfo/

Thanks...  interesting stuff. 
Have heard about exalted carrier reception on AM using SSB mode, apparently a similar situation.
Das Radiobunker somewhere in Michigan

Offline Josh

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Re: weak signal reception
« Reply #3 on: August 01, 2018, 1915 UTC »
With weirdness like the Luxembourg effect on the low bands, it wouldn't surprise me to find any activity on a specific freq enhances ionospheric activity on nearby freqs.

I've seen it on hf before, I'm talking to someone and then the person I'm talking to responds to someone I can't hear who has just joined us, then a second or two later the other person pops up and stays loud and clear after they've stimulated the ionosphere with their rf a bit. I call it salting the ionosphere.

A friend who worked at haarp and is still up there at the university did plasma research that shows the ionosphere doesn't refract or reflect radio signals, it re-radiates them on an electron level. His research was front page on qst back in the day. A signal hits the mass of electron jello up there and the electrons store it, then reradiate it, snapping back to their original power level more or less. The trick is to find a way to use the ionosphere as an amplifier, there's zillions of amps and thousands of volts of free solar electricity up there for the folks who find out how to make a triode out of the earth and ionosphere.

One of the shuttle missions released a tether that was x meters long to drag it through the ionosphere and see what they got. Well, there was so much current flow the tether melted near the shuttle end and as the tether was floating away, it built up enough charge to arc over several feet to the shuttle, mind you this is in orbit where the air is mighty thin so the dielectric was huge and the spark had to be even huger. And yes it scared the shit out of the shuttle folks.

http://articles.latimes.com/1996-02-26/news/mn-40319_1_space-shuttle-columbia

https://patents.google.com/patent/US4686605A/en
Conveniently located near Vincennes Indiana.

Offline pinto vortando

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Re: weak signal reception
« Reply #4 on: August 01, 2018, 2142 UTC »
"Those are some tether dynamics we did not want to see".   :o
Das Radiobunker somewhere in Michigan

Offline Tim Bucknall

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Re: weak signal reception
« Reply #5 on: September 01, 2018, 1713 UTC »
Been noticing an interesting affect when tuning around on the NDB band.  If a strong local beacon is tuned in, it seems to pull up weaker signals on the same or adjacent channels.  Is there a name for this or is it just my imagination.  ???

cool thread
how far either side of the centre freq (approximately) does the effect work?


Offline pinto vortando

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Re: weak signal reception
« Reply #6 on: September 01, 2018, 2215 UTC »
Been noticing an interesting affect when tuning around on the NDB band.  If a strong local beacon is tuned in, it seems to pull up weaker signals on the same or adjacent channels.  Is there a name for this or is it just my imagination.  ???

cool thread
how far either side of the centre freq (approximately) does the effect work?

In my experience, to use the signal from a strong local beacon to exalt other weaker signals, the two signals must be very close together, either on the same frequency or maybe 1 or 2 kc apart.
Das Radiobunker somewhere in Michigan