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Anyone care to opine why reception has been so dismal on the VHF-hi bands for the past few weeks. I know it's not just me, 'cause the dispatchers (CENCOM) are constantly being told by the field units they are scratchy and hard to copy. Seems like it happens at certain times of the year that are dry.

Sun Storms have been very active lately.

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"A well regulated breakfast, being necessary to the healthy start of the day, the right of the people to keep and eat food shall not be infringed."

Yes, this is reality. Oh my, . . . where to begin.

Atmospheric conditions is always a favorite. Temperature inversion layers ? Antenna type / design - and the nulls realized when high gain mountaintop antennas can't propagate the signal directly below them in the valleys ? Time of the season ? Voting receivers that are off-line ? VHF noise floor ? Topography shadows ? Refraction and refection, or rather the lack thereof ? Lack of snow on the slopes of the nearby mountains ? Age, condition, or damage to the coaxial feed lines ? Bird nests on the towers ? Local receiver desense ?

When I get this question posed to me at work, I simply reply: Its "F-M" (funny magic).

The first generation celluar AirCard for my assigned MDT would really tear up my VHF radio receive quality. The AirCard has since been upgraded - so no more concerns there. My new (modern) H.E. style washing machine at home acts like a broad spectrum menace to any VHF / UHF signal reception at my house.

Many years ago we found the old 2Ghz analog microwave link systems would freak out whenever the low setting sun would directly enter it's west facing path.

I've also noticed this poor signal quality condition within other various VHF systems - at different times during the day. The best VHF reception / performance I've experienced is just after the rain has stopped and the earth is still wet.

Colleagues tease me that I should abandon VHF as an anachronism, but I'm just too stubborn. I might suspect that VHF signal quality could perhaps be even more challenging with a narrowband digital signal emission mode - unless additional transmitters (simulcast) are properly deployed within the engineered system ?

The WSP has discussed the idea of deploying a four-frequency VHF 6.25Khz channel P-25 system as a testbed. Those design efforts and field testing would be worthwhile to follow.

Anyone else have some helpful (industry related) insight here ?

Your radio's broke :mrgreen:

Really... Check everything... Sometimes the corroded connector will work when damp and fail when dry!

I have actually been experiencing ENHANCED VHF propagation from my QTH on two meters, at least... although the vegetation growing around that antenna needs to be cleared out... I have still been hearing an Echolink node inappropriately located on an FM simplex frequency, located well up North in British Columbia someplace, on my favorite simplex frequency. The late-summer Puget Sound temperature inversion is to blame here as the rest of the year that signal simply doesn't make it here otherwise.

No trouble with LE2, Fire 1 and WSP from downtown Olalla on Saturday morning.
Eric
KB7DQH

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That is how the people at DARPA think. they take things and use them in unconventional ways, to see what happens.

I run PDW on a few PC's to monitor the pages sent SNOPAC, SNOCOM and ValleyCom. I can also confirm that as of the last 2 weeks the decode rate has went in the toilet. One of the PC's that normally decodeds at 100% has been running in the low 70's. So ya, VHF reception has indeed been poor.

As mentioned, I chalked it up to the recent sun activity.

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Neah Bay Public Safety is having trouble hearing their own people due to the higher noise floor but hearing Lincoln City Oregon almost full quieting... Like Craig said... Funny Magic! :mrgreen:

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"A well regulated breakfast, being necessary to the healthy start of the day, the right of the people to keep and eat food shall not be infringed."

Heard Pender Island fire tone out on 154.920 just south of Olympia yesterday. But I haven't heard Yakima area for a while.

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"I was installing un-programmed radios"

No problems here. :mrgreen:

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Its been jumpy here...some days super great....some days can't even hear repeaters only 50 miles away.

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Mt Wave SAR member
Support Search & Rescue: Get Lost!
http://www.mwave.org

We've been having similar issues with UHF in Southern New England.

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-Tom, W1WSO -- Plymouth, CT
http://tf.sdf.org/monitor/

Oh god....I remember the foliage would screw up UHF in the fall in Upstate NY.

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Mt Wave SAR member
Support Search & Rescue: Get Lost!
http://www.mwave.org