Sorry to all about the link. I normally check my links before sending them
but I forgot to this time.
It's under the "support" tab and then click on "water and rain testing"
73's and thanks for the correction.
RoD
KD0XX
A good friend will come and bail you out of jail,
A TRUE friend will be sitting next to you saying.....
"DAMN THAT WAS FUN"
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com]On Behalf Of Steve Katz
> Sent: Friday, July 27, 2007 6:00 PM
> To: sad.tip@verizon.net; Hector@xe2k.net; Tower Talk
> Subject: Re: [TowerTalk] m2 6M7 SWR change with rain
>
>
> That M2 link just takes you to the main website, not specifically to
> anything about rain and 6m beams. I took the liberty of copying
> just a few
> sentences on this specific subject (pasted from M2 website
> directly, credit
> to them!):
>
> "CLEARLY THE CAUSE OF ANY SHIFT IS BECAUSE THE ANTENNA IS A CRITICALLY
> TUNED, HIGH GAIN YAGI WITH A VERY LOW FEED IMPEDANCE. THE GAIN
> CURVE IN THIS
> DESIGN PEAKS BETWEEN 50.200 AND 50.300 BUT IS ONLY DOWN .06 DB AT
> 50.000 AND
> 50.400 MHZ SO EVEN IF ALL THE WORKING PARAMETERS OF THE ANTENNA
> SHIFTED DOWN
> 200 KHZ, YOUR GAIN WOULD ONLY DROP BY .06 DB. AT 50.1 MHZ.
>
> THE MOST TOUCHY SECTION IS CLEARLY THE DRIVEN ELEMENT TIPS. ANY DIELECTRIC
> NEAR OR ON THE TIP OF THE ELEMENT WILL DRIVE THE FREQUENCY
> DOWNWARD. EVEN A
> PLASTIC CAP OVER THE END WILL HAVE THAT EFFECT. WATER IS A DIELECTRIC. THE
> RAIN OR WATER DROPS ALSO INCREASE THE DIAMETER OF THE ELEMENT MAKING IT GO
> EVEN LOWER IN FREQUENCY. IF THE DIAMETER OF THE DRIVEN ELEMENT
> WERE LARGER,
> WATER WOULD HAVE LESS EFFECT. WIND AREA AND COST WOULD GO UP
> UNFORTUNATELY.
> ENGINEERING WILL LOOK INTO JUST INCREASING THE EFFECTIVE TIP
> DIAMETER OF THE
> DRIVEN ELEMENT TO REDUCE THIS EFFECT. RESULTS OF THESE TEST WILL BE
> ANNOUNCED FOR THOSE OF YOU WHO NEED HELP IN THIS AREA."
>
> This is exactly what I said it was...rain droplets on the element tips.
> When the wind blows them off or the sun dries them out, everything returns
> to normal. This is normal behavior for a narrowband yagi
> antenna, from what
> I've seen, they all do it.
>
> -WB2WIK/6
>
>
>
> -----Original Message-----
> From: Sadtip [mailto:sad.tip@verizon.net]
> Sent: Friday, July 27, 2007 2:57 PM
> To: Hector@xe2k.net; Tower Talk
> Subject: Re: [TowerTalk] m2 6M7 SWR change with rain
>
> Hector,
> M2 put together a pretty complete description and explanation of the
> problem at....
>
> http://www.m2inc.com/index2.html
>
> They used a 6M5X but it's still worth a read and might help.
>
> 73's
> RoD
> KD0XX
>
> A good friend will come and bail you out of jail,
> A TRUE friend will be sitting next to you saying.....
>
>
> "DAMN THAT WAS FUN"
>
> > -----Original Message-----
> > From: towertalk-bounces@contesting.com
> > [mailto:towertalk-bounces@contesting.com]On Behalf Of Hector Garcia XE2K
> > Sent: Friday, July 27, 2007 4:42 PM
> > To: Tower Talk
> > Subject: [TowerTalk] m2 6M7 SWR change with rain
> >
> >
> > Hi guys:
> >
> > A friend just install the 6M7 in his office tower
> > and he report that his antena in the last rains the
> > swr change from the perfect 50.125 1:1 to 49.9 1:1
> > when the antena is WET , just dry and the SWR back to
> > 50.125
> >
> > I have a 6M7JHV in the box to be installed at 150ft
> > and really i will like to know if adding some clear
> > spray or paint to the driven will reduce or eliminate
> > that problem of SWR change when WET.
> >
> > any solve the problem ? any solution avaliable
> >
> > or just live with that ?
> >
> >
> > Hector
> >
> > Hector Garcia XE2K / XF1K
> > Mexicali B.C DM22fp
> > P.O.Box 73
> > El Centro CA 92244-0073
> > USA
> > http:// www.xe2k.net
> > http://www.dxxe.org
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
>
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