how do different weather conditions effect scanners?

[Ncfirewire]

how do different weather conditions effect receiving ?? some days i can pick up just about everything for miles and miles away and then one day quite a few channels are coming in horrible such as today and it is 80 and clear today.

it just seems old how i can go days and days with crystal clear reception and then get a day with horrible

does heat and humidity do anything? clouds and rain?

thanks

 

[scanphreak]

atmospheric conditions play a big role in how RF energy propagates from one place to another. On days or nights when you can hear stations from several miles away, including hundreds of miles away, or when you hear several different stations talking on top of each other, in the VHF/UHF bands this is what's called Tropospheric Ducting, or just ducting. This occurs when hot air mass and cold air mass collides just above the ground wave level and causes RF energy at those frequencies (VHF/UHF) to sort of "surf" or flow in between like air or fluid moving through a duct from one place to another. This can take a signal with very little power and send it several hundred miles across land and sea.

This usually happens in the evening time when the heat of the day is met with cold air from a low front, or very early in the morning before the air starts to heat up. Also you have Solar radiation playing a big part in this too. Solar flares, storms, and sun spots can bombard the earth with radiation causing the different levels of the ionosphere to change and usually the layers that would reflect signals back to earth will absorb RF energy and it becomes lost. High levels of Solar activity will have negative effects on VHF/UHF signals.
To learn more check this page out: Tropospheric propagation - Wikipedia, the free encyclopedia

 

[Ncfirewire]

i have heard about that before but i'm having trouble certain days on stuff no more than 20 miles away

and it is usually an all day problem and then i will go 20 days will perfect clarity then then again i get one bad day

 

[ka3jjz]

We have a number of articles on this subject here...

DXing Above 30 Mhz - The RadioReference Wiki

Bill Hepburn's site has maps that attempt to project when tropo is going to be in a particular area. At the bottom there are links to some more descriptions about what tropo is all about.

Keep in mind that although this is a common mode (especially so during the late spring/summer), there are other weather related modes, and even the sun gets into the act at times. Lightning has been known to momentarily ionize the atmosphere, conducting signals for a few seconds; and when the sun really throws a flare or two our way, it's quite possible that they will ionize the upper regions of the ionosphere so that VHF (and even, at times UHF) signals travel 1000 miles or more (hams chase DX on 2 meters and 432 Mhz just for things like this...). So the weather can and often does have a significant impact on DX reception in the VHF bands and higher

However let's take a step back. I would check the coax connections and the coax itself for weather related damage. When's the last time you changed it? After a few years, it can and does degrade. What about the antenna itself and the connection to the coax? All of this can play a role.

HTH...Mike

 

[N8IAA]

i have heard about that before but i'm having trouble certain days on stuff no more than 20 miles away

and it is usually an all day problem and then i will go 20 days will perfect clarity then then again i get one bad day

Be more specific about what frequencies and what you are monitoring. We can just give general answers about weather conditions and how frequencies are affected. There are other conditions that may factor in to how the signal propagates.
HTH,
Larry

 

[VO1GXG]

Also note that if you have poor antennas, poor coax and poor connectors weather conditions such as humidity , rain , heat , snow etc will cause problems. I have poor connectors on one run of cable and when it rain's i can literally hear the rain drops on the antenna.

 

[kjo1981]

We had an extremely warm day today here in E. Iowa, as did most of the Midwest. And I'm hearing a lot of traffic from across the river in Illinois on my handheld Bearcat this evening that I do not typically hear. I heard fire pages on the same freq as the local FD pagers and LEO traffic on the same freq as the local PD.

 

[w2xq]

:twisted: And we recently had a solar disturbance that for a while took out 440/500/800 MHz reception from towers more than 5 or 8 miles away, unusual to be sure. Temperature inversion (heating and cooling), differences of air mass temperatures (fronts), widespread forest fire smoke, volcanic ash, widespread heavy rain, and fog are just some of the things we've observed over the years. HTH,

 

[Rt169Radio]

I think the seasons effect radio signals too,you know with the different weather and the leaves on/off the tress.

 

[RoninJoliet]

U guys are right on as we have a "warm" front drapped across northern ILL today and VHF-UHF are wide open...Hearing what sounds like stations in Wisconsin and Indiana and a couple P25, they will be gone tomorow.....

 

[eriepascannist]

I am not sure for the reason of this, but I have noticed that on hot, humid summer days, mostly during the afternoon, all bands (VHF in particular) close up, to the point where I cannot hear my local fire dispatcher. I have found that the best time to hear radio signals is on clear, cold winter nights, and the worst is hot, humid summer afternoons, ducting and the like aside.

We have recently had a lot of signals coming across from Canada to my location on Lake Erie, far more than usual, since this hot weather set in. I believe that's caused by the hot air over the cooler lake causing a kind of ducting...?

Anyhow my freqs are jammed with Canadian traffic. It's even to the point where I can't hear my local FM brodcast radio stations as they are being choked out with Canadian channels on the same freq.

Interesting stuff.

 

[w2xq]

We have recently had a lot of signals coming across from Canada to my location on Lake Erie, far more than usual, since this hot weather set in. I believe that's caused by the hot air over the cooler lake causing a kind of ducting...?

Anyhow my freqs are jammed with Canadian traffic. It's even to the point where I can't hear my local FM broadcast radio stations as they are being choked out with Canadian channels on the same freq.

You got it. The air over land cools at a different rate than air over water, not to mention signals over water propagate better than over land. On New Jersey's barrier islands, "normal" reception includes the Boston area to the coastal areas of Virginia and North Carolina. When I'm staying on one of the Thousand Islands (near Clayton) 2m/70cm repeaters up and down the river are significantly stronger than those inland in New York and Ontario. HTH.

 

[eriepascannist]

I thought so. If I ever hear a signal I don't recognize, I usually look to Canada first. This morning, a warm and humid one, my usually quiet local freqs were completely jammed up with signals I didn't recognize. Unfortunately there was never any identifying material for me to pinpoint where they were coming from. The one station on my local FD was a fire dispatcher that sounded like he was on a trunked system simulcast; I don't know of many of those in the area.

 

[RedPenguin]

Weather definitely does seem to play a major role.

I for example get what I call "frequency blackouts" where for no appearent reason channels I normally can hear well suddenly go silent except for random extremly staticy transmissions.

I tried different antennas and even different scanners and it is never solved.

So my only explanation is weather because most I listen to is UHF 453.xxx and at most transmitters 25 miles away.

 

[wheels63]

I wish my scanners would work all day as good as they come in in the early morning..


BC60XLT
BC72XLT
Pro-2036
Pro-2039

I`v lost count on how many scanners I have had.At least 15. Favorite scanner is the Radio Shack Pro-2036(Uniden890XLT).

Tom