signal reception

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Whiskey3JMC

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What band(s)? More than one frequency affected? Can you provide an audio sample?

One potential reason I can think of if it's just one frequency or more than one in close proximity to each other (particularly VHF, sometimes UHF) would be digital emissions (DMR, NXDN, P25, etc) from a more distant station on the same frequency since propagation is more favorable on certain summer evenings when conditions are right. Hard to draw a definite conclusion though without a sample of what you're hearing. Each mode I mentioned is a clickable hyperlink with raw emissions samples if you want to see if they sound similar

73!
 
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mmckenna

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Yeah, I'd probably say it's not the temperature, but what causes the higher temperature. Weather systems can create some interesting RF effects. Warmer weather often helps with certain types of ducting, and that can result in interference from distant co-channel users. I have a Marine AIS receiver that works on VHF marine band. When the weather is warmer, tropospheric ducting can bring in signals from several hundred miles away (I've seen hits at 700 miles on my receiver).

Add in lightning crashes on lower frequencies...
Wet pine needles can impact higher frequency(800MHz etc) coverage.
Heavy storms, etc. Its all pretty interesting.
 

mmckenna

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Non HF? Wow, that's great DX
Yeah, VHF AIS. Pretty amazing.
May 10th, 2020, I had a hit from 781 miles out in the Pacific.
I'm running a 5/8th's wave VHF base ground plane antenna with about 40 feet of LMR-600. I have a clear view out across the ocean, and I'm about 800 feet up.
Today, my average was in the 285 mile range.
Class A AIS systems run 12.5 watts, but they often are on high gain antennas mounted on the mast.
 

bob550

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Non HF? Wow, that's great DX
During my teen years in the 1960's, living south of Boston, MA., I owned a 12" portable black and white TV. I can't remember the time of year, but one night after 11 p.m. I was tuning past our local channel 2 which had gone off the air for the day, and saw a very faint and snowy image. I stayed with it long enough to identify the station as transmitting from Green Bay Wisconsin, a distance of around 860 miles! This achievement was even more fantastic when you realize I received this station only using the TV's built-in monopole antenna!
 

Ubbe

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Can hot weather cause a radio to have static noise on receive?
If the weather makes you receive much more signals and with higher signal levels, then it depends on the receiver if it might get overloaded and loose sensitivity so that the result are a noisier signal. A good receiver should be unaffected but scanners usually do not have a good receiver.

And as already mentioned, if a far away signal are received it could be too close to the monitored frequency and interfere. The FCC hands out frequencies so it shouldn't happen in a geographical area, but the area you can receive might be huge in the right weather conditions and frequencies could then interfere with each other.

Some 25-30 years ago it was possible to hear US firebrigades and others at 30MHz-40MHz in Sweden several times each summer that lasted a couple of days each. It was always from the east coast and one frequency announced itself with a female voice "This is a repeater in Boston". I usually have a search range of 30-45MHz always going but I have never heard anything since those years. It was always a narrow band of 1MHz-2MHz that was heard and it shifted slightly in frequency to another part of the band with each time it could be heard. The 11 year sunspot cycle where at a maximum at that time and later cycles have been weaker, the latest one that ends now was only half the strenght and the weakest since a 100 years.

/Ubbe
 

KA4PQA

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I have two receive radios,one in the bedroom and the other in the living room.The living room radio does receive but with a delay compared to the one in the bedroom and sometimes the delay is enough to cause it to miss traffic.My wife and i live on the ground floor of an apartment building.The radios antennas are on home made window mounts in the windows.The windows are on opposite sides of the building.What could be the cause of the delayed reception between the two rooms?
 

KA4PQA

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The radio in the bedroom will receive our neighboring towns city and county fire dispatch with no problems and it is 15 miles away.The radio in the living room will receive the same dispatch traffic on and off.What could cause one radio to receive and the other one not to?The bedroom radio antenna is in the window same side as facing neighboring town while the other is not.
 

N1GAW

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There could be other electric appliances nearby interfering or even something outside line of sight that is causing issues. Take the living room radio and move it to other locations for a few hours or more in each spot to see if it makes a difference.
 

ofd8001

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It is sort of along the lines why you try on shoes before you buy them. Even though two pair have the same sizes, one may fit different than the other. Some scanners may receive better than others, or one could have been jarred slightly just enough to loosen antenna circuitry.

Then you got all the things mentioned above. With radio waves being invisible, one never knows what is going on inside a structure. The structure itself could be "soaking up" RF just slightly, too. (Wires in walls, metal HVAC ducts, possible foil-backed wall insulation and so on.)
 

KA4PQA

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I made some living room radio station changes over the weekend where my receive/transmit base radio is which is one of the 2 radios which receives neighboring towns fire frequencies and due to living room changes have now lost that reception.Should i feel guilty having done that because my wife's family lives in that neighboring county as i have always made it a point to keep that reception to keep that reception for the family's sake.
 

KA4PQA

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If you live on the bottom floor of an apartment an are blocked by house rules from being able to put your antenna outside and you have so much coax inside that you are having to keep it coiled up so as not to have a whole lot on the floor can that affect your radio signal receive?
 
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