@richpowers unless that is because that TIS station in the next county making it seem that way even though it's not clearly heard. I know the further I go downtown the noise gets worse on 1630.
I have moved down to 1630 to make way for a government TIS station. The modulation seems to be a little more robust on 1630 than it was on 1700. I drove around the usually area I normally travel and only noticed a slight difference in the coverage. Little more hiss in places, but overall not a real big change.
The difference in frequency is, what, 70 Khz. About 4%. Other than noise considerations, which appear, at least in your area, not to be an issue, there should be little difference in antenna efficiency and range.
When I operated AM a while ago using a Talking Sign, I noticed little difference in range between 1570 and 1650/1660, which were the clearest in my area at the time. I ultimately decided on 1570, as there were more radios able to receive it than on the X band (including mine).
I didn't do the tone test as described previously in another thread, but the signals faded out and became unlistenable (to my ears at least) in approximately the same location for both frequencies. I was getting slightly over a mile in an area that was only partially built up (and then with residential wood housing), and with great ground conductivity (essentially a flood plain).
@artisan-radio The noise level comes up as going further in downtown on 1630. It's more noticed on 1630 than 1700. All other areas pretty much the same.
Somewhere archived in one of the forums R Fry had made a graph conisting of about 4 different frequencies, ie: like 1700, 1600 and 1500, 1400. The chart showed the resulting feild strength capability potentials of each frequency with a compliant installations.
It's great to hear your getting acceptable range on the lower frequencies, but I'm real curious about your statement about I sounding more "robust" on 1630 than it does on 1700...
Your increased noise level on 1630 heading into town is due to1630 providing less feild stregth to overcome that interference than 1700 does.
@richpowers On the SW 300 modulation monitor it's showing a better modulation swing and higher peaks. And it sounded cleaner and better dynamics than 1700.
Thas really interesting Roy. Could there be a correlation between the chosen frequency and the dynamics of the received audio? -
It's also possible that the atmospheric conditions today is quite different than the other day and that's why.
@richpowers Nothing here has changed here weather wise since I made the frequency change at 930am, I noticed it right after the change. I don't know, I'm going to have to research that one.
@wefr Well.. I notice my AM reception (listening to local licenced stations) can vary throughout the day, sometimes sounding "brighter":and other times sounding a little muddy for no particular reason.
But it's all really above my head, I'm only speaking in speculation and ponderation. But I've noticed in the past with my part 15, Some days I'd think wow,, it sounds better today for some reason.. but next I start thinking it's probally all just in my head and it's actually no different... but I'm never sure.
Bottom line, if your producing a good sounding signal and it's reaching your intended audience, you've station is a success!
@richpowers On the SW 300 modulation monitor it's showing a better modulation swing and higher peaks. And it sounded cleaner and better dynamics than 1700.
Approximately what is your elevation there in W. Virginia? I'm at 1,100 ft.
@richpowers On the SW 300 modulation monitor it's showing a better modulation swing and higher peaks. And it sounded cleaner and better dynamics than 1700.
Approximately what is your elevation there in W. Virginia? I'm at 1,100 ft.
What made you ask him that??
A google answers: "The city of Fairmont, West Virginia, is located at an elevation of 984 feet (300 meters) above sea level. Fairmont Municipal Airport, located within the city, has an elevation of 1,029 feet (314 meters)..."
Your question implies it makes a difference, and I dont recall having previous discussions about what effects might an areas generall geographic elevation have on a part 15 AM propigation?
- I guess it would make a difference, but never considered it before.
I still have the question about your question..
Does the areas geographic elevation have an effect on a part 15 AM propagation?
@richpowers Unless it's up really high like on a mountain top, tall tower or high rise building that above average terrain considerably. Not really
@wefr Yeah, but I didnt mean how high the transmitter was relative to the surrounding area. - I meant the average terrain in general. Like Denver Colorado, that's high terrain, obviously there are different average barometric pressures and what not then what the average in say Texas for example.
Well, we all know ground conductivity of an area plays a huge role in AM propagation, so it seems reasonable to assume the average terrain elevation and the atmospheric differences that comes with it it would somehow have sure effects on 100mw radio signals.
Seems to me anyway.