Improved High-VHF reception when raining (whenever antenna gets wet)

[Cemguy]

I'm in central PA. I have a large 8-bay UHF antenna and a converter box for watching digital OTA TV.

I noticed that ONLY when it rained could I receive a strong enough signal on channel 27 (actually broadcasting on VHF 10) to make it "viewable". I thought it might have something to do with signal scattering, but...

I tried having someone spray the antenna with water from a hose, through a spray nozzle and am able to, very consistently and repeatably, get the same results (wet antenna - good reception on 27/10; once the antenna dries out, signal too weak for viewing on 27/10).

Anyone else have any idea what's going on here? Wetting the antenna elements definitely greatly increases the signal quality on that channel (ABC 27 - broadcast on VHF frequency 10).

At the same time, when the antenna is wet, reception on UPN 15 (actually broadcasting on UHF 23) goes from viewable to too weak to view).

Other channels do not seem to be affected.

I'll probably be adding a VHF antenna and a pre-amp, but I thought that maybe one of the "experts" in the forum could shed some light on what's happening here.

Thanks

 

[boba]

Your TV antenna is an electrical circuit so water changes the condutivity. How long has it been exposed to the weather is there corrosion at contact points?

 

[Cemguy]

Practically brand new. No corrosion. no wear.

Remember, it's a UHF antenna, so the VHF reception is not going to be that good to begin with.

The majority of the stations I receive (with the exception of the 15/23 channel) are absolutely unaffected by wet vs. dry.

 

[Jim5506]

Let me assume you have an old version CM4228.

The improved reception on VHF when wet means that the back screens need to be tied more firmly together.

If you make the back screens one electrical unit, the antenna's VHF performance is enhanced.

 

[Tower Guy]

I thought that maybe one of the "experts" in the forum could shed some light on what's happening here.

It may have nothing to do with antenna performance. If you happen to have power line noise, it tends to bother VHF more than UHF. Power line noise also tends to go away during rainy weather.

 

[Jim5506]

That does not explain why spraying the antenna with a water hose also helps.

 

[Cemguy]

The antenna is a brand new Terrestrial Digital DB8 (I bought it from Antennas Direct).

I suspect that "power line noise" could be a factor, but if that is really the case I don't think it would explain the enhanced quality of 27/10 when wet vs. the degraded quality of 15/23 (unless UHF is much less affected and a thin film of water on the elements reduces the power line noise effect???).

If the back grid is not properly "united", wouldn't that be a problem "across the board" for all channels, or could that just affect "weaker" ones?

I actually did use a continuity meter to make sure all the back grid sections were electrically connected.

Until I get an additional VHF antenna and a pre-amp, I've set up a ladder and duct-taped a hose/nozzle to it. Sounds screwy, but when I want to watch 27/10, I just turn on the hose; when I want to watch 15/23 I make sure the hose is off. Crude, but it works.

 

[Jim5506]

The DB8 makes no claims at being able to receive VHF, so anyhthing you are getting on VHF is serendipity.

I assumed you might have the CM, because the old 4228 does have some VHF capacity. When the back screens are tied together they approximate the 1/4 wave frequency of some VHF high channels giving it mild VHF capability.

 

[Splicer]

Nevermind...I read the OP wrong...