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wolfcreek
join:2003-12-02
Pagosa Springs, CO

wolfcreek to lutful

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to lutful

Re: Yagi antennas in winter

actually the original M2 version and several other brands we tried(dont remember brands anymore got smart and got rid of 900 mhz shots) had elements insulated from the boom and they would not work in any moisture level.

There is a good chance any conductive surface within one wavelength of the antenna will affect its operation. A pile of wet snow is conductive. Another problem is weight. Heavy wet snow on a radome will be quite heavy.
54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

1 edit

54067323 (banned)

Member

said by wolfcreek:

actually the original M2 version and several other brands we tried(dont remember brands anymore got smart and got rid of 900 mhz shots) had elements insulated from the boom and they would not work in any moisture level.

I wonder if that was the result of the moisture un-insulating those elements from the boom?

I know with UHF OTA TV antennas the insulators, due to UV damage, change from a nice water beads off of the surface material to a matt surface that stays wet until heated enough by the sun causing the moisture to flash off, combine that collected moisture with inpurities in the air and those insulators could very well become quite conductive.

WHT
join:2010-03-26
Rosston, TX

WHT to lutful

Member

to lutful
said by lutful:

Are you saying that I should NOT have pursued a Yagi solution

No
said by lutful:

Or are you saying that I should NOT have mentioned a solution

No
said by lutful:

Or are you saying that I should NOT have mentioned a solution

No
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful to wolfcreek

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to wolfcreek
said by wolfcreek:

original M2 version and several other brands ... had elements insulated from the boom and they would not work in any moisture level.

This is how I am interpreting what you are saying: some companies actually sold Yagi's which "would not work in any moisture level" and managed to stay in business long enough to make rod-inserted-into-boom type Yagis which work fabulously in rain, snow and ice conditions.
said by wolfcreek:

There is a good chance any conductive surface within one wavelength of the antenna will affect its operation. A pile of wet snow is conductive.

Why does snow/ice NOT affect rod-inserted-into-boom Yagi designs in your opinion?
said by wolfcreek:

Another problem is weight. Heavy wet snow on a radome will be quite heavy.

That is why I was originally suggesting radome protection ONLY for the driven element and only hydrophobic coating for the reflector and directors.

Hollow copper tubes (filled with closed-cell foam) inserted into PVC boom is lighter and mechanically more robust. Also easier on masts and small towers. Just another alternative.
54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

1 edit

54067323 (banned)

Member

said by lutful:

That is why I was originally suggesting radome protection ONLY for the driven element and only hydrophobic coating for the reflector and directors.

Hence the design Cushcraft engineered years ago into their yagis.




That little black tube is the radome protection for the active element.

What you are proposing is old news.
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful to wolfcreek

Premium Member

to wolfcreek
wolfcreek See Profile ... found a 2005 thread where Semaphore See Profile reported that his Cushcraft PC9013N "rod-inserted-into-U-boom" design Yagi stopped working in freezing rain ... so those kind of design is not immune.

»Yagi Radome ?

I also looked at Kathrein Scala full radome Yagi dimensions - separation is about 1/4 wavelength from the end of elements and about 1/2 wavelength above/below the boom.

Jason
Stowage Class Traveler

join:2001-01-24
38.2967 Lat

Jason to Anon

to Anon
Lets pause for a moment, and collect our thoughts, shall we?

Great info here, but its getting bedded beneath, well frankly... Crap.

Give me a moment to figure out what to do with this equally insightful, and inciteful thread.

Thanks