• Please note that Audiokarma will be offline briefly for updates early on Monday morning, September 28th.

Tropospheric ducting- Reality or myth?

B

bortz

New Member
I've been watching the Hepburn TD site and seeing if I can get stronger signals or even previously non existent signals during periods of high TD and really haven't seen any difference in reception.

What's your opinion on tropo ducting allowing better reception on FM during a period of high activity?
 
Register to hide this ad
I think there's something to it- There used to be this FM antenna mounted way high on my granmother's apartment, a building which was itself built on a little rise. One GORGEOUS spring day about 15 yrs ago, I took a JVC TV/cassette/radio & hooked it up to the FM antenna-WOW ! The whole FM band was one solid station-I was pullin' 'em in from way over in the Carolinas, from Marietta, Georgia, down to near Nashville-All from my extreme NE Tennessee location.
 
It's definitely real although I've never experienced it with FM broadcast. I have however talked to people on my 5 watt 146 mhz (2-meter) ham walkie-talkie several hundred miles away using just the simple (crappy) rubber duck antenna. And this was on simplex; not standing on a mountain top, through a repeater or mother ship link.
It is unpredictable but quite exciting (in a nerdy way) to experience.
JimB
 
It is a reality, but much more ducting of RF occurs during warmer months. I think that once it warms up a bit you might be able to notice a slight improvement in signal strength if your in a corridor. You need moist warmer air over cooler to facilitate the bending of the Line-of-Site path.

I have worked in wireless for over 24 years utilizing Troposcatter systems designed to skip off of the ionosphere while in the military and engineering and construction of commercial broadcast and communications systems designed to actually minimize any ducting of signal. It can be especially troublesome in cellular contributing to neighboring site handoff problems.

Regards,
TB
 
I used to sometimes get TV out of Rhode Island in Bangor, Maine, a distance of 250 miles. Had a humongous Radio Shack TV antenna on a twenty foot mast. Oddly, Boston stations didn't ever come in that I remember.
 
It is a reality, for VHF analog tv as well as radio.

Here in the Big Apple, it tends to be better when it's hazy hot and humid. August is a good time. I received a few notable broadcasts here and there but didn't really keep a log which is silly I now realize.....
 
For the past ten years, I've always looked forward to April through June, when warm and unsettled weather moves in on the chilled-from-winter East Coast. I've always been able to pick up Florida, Alabama, Georgia, and occasional Louisiana TV stations on VHF channels 2 through 6 up here in SW Mass. during these times. FM is harder because it's higher on the spectrum than channel 6. I've never had any luck any other time of year.
 
Yes tropospheric ducting is real. Where we are on the coastal part of Northern Queensland, as an amateur radio operator I see tropospheric ducting enchancement all the time on the 2 m Amateur Radio band and occasionally sporadic 'E' enhancements which are often spectacular, mainly during the summer months.

Tropospheric ducting often lifts signals levels of the order of 3 to 6 db, based on observations in this radio shack. Regards, Felix aka catman (vk4fuq).
 
OvenMaster said:
FM is harder because it's higher on the spectrum than channel 6. I've never had any luck any other time of year.
Click to expand...

I always thought that tropospheric ducting was supposed to favor higher frequencies, and would come down into the FM broadcast spectrum from the higher channels as it strangthened, whereas Sporadic-E tended to favor the lower portion of the VHF spectrum, reaching FM from the lower end of the band first as it traveled upward in frequency as the opening became more intense.

In other words, if one was a television DXer, they'd rely on E-skip openings for the lower VHF channels, and tropo for the higher VHF and UHF ones.

I once pulled in a station in Aurora, IL on 107.9 here, back when I had a 10-element Yagi on the roof. It was roughly 250 miles... not sure if it was tropo or fringe, or a combination of the two. Back in those days we'd also occasionally pull in Cleveland on Channel 8 on summer evenings if conditions were good.
 
Ah! Then it's likely that I am confusing E-skip with tropospheric ducting! Very possible! :(
If this is the case, then I've never experienced tropo ducting DX.
Tom
 
You must log in or register to reply here.
Back
Top Bottom