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Subject:
From:
John Miller <[log in to unmask]>
Reply To:
For blind ham radio operators <[log in to unmask]>
Date:
Sat, 10 Nov 2012 22:39:14 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (69 lines)
You are right, you're loss is what makes it look better to the radio. That 
sounds like my vertical, swr sweet spot on 80 is extremely narrow. I'd 
wonder if you could try a different counterpoise and see if that improves 
it. If not, and it's working for you I guess I wouldn't worry about it but 
stuff like that with me, nags at me something horrible.
----- Original Message ----- 
From: "Tom Behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, November 10, 2012 10:23 PM
Subject: Some antenna theory elmering needed again


> Hi, all.
>
> As some of you may remember, I purchased two half slopers from W8AMZ
> antennas about a year ago.  One was a 160 meter antenna, and the other was
> an 80-meter antenna.
>
> Although it is a compromise antenna for sure, I have had at least some
> success with the 160-meter antenna, in that I can keep my SWR's down below 
> 2
> to 1 on the lower half of 160, which is where I mainly like to operate
> anyway.
>
> However, I have not had as much luck with the 80-meter half sloper.
>
> The radiating element of the antenna is roughly 30 feet long, and the 
> other
> half of the antenna is grounded to my 40-foot mast as a sort of
> counterpoise.  The center of the antenna is up about 30 feet.  The antenna
> is fed with about 30 feet of RG8X coax.
>
> The resonant frequency of the antenna is around 3.900, but the sweet spot 
> is
> very narrow.  My SWR's are up around 5.0 to 1 at both the top and bottom 
> of
> the band, with varying SWR's in between, ranging between 2.1 to 1, and 4 
> to
> 1.
>
> Based on my experience out at the RV with my G5RV, I decided on a whim to
> try something tonight.  I pieced together about 100 feet of coax, and put 
> it
> as close to the transmitter as I could get it.  When I did this, my SWR's
> improved significantly.  The were 3.0 to 1 at the top of the band, 4.1 to 
> 1
> at the bottom, and below 2.1 to one through much of the rest of the band.
> The antenna tunes across the band with the TS590 auto-tuner.
>
> My question here is:  By doing what I have done here, am I just fooling
> myself into thinking things are better when they really are not?  I 
> suspect
> that anything I'm gaining by reducing the SWR is going to be lost in all 
> the
> extra coax I've now introduced into the system.
>
> Am I correct with my reservations here, or should I not worry about things
> as long as the TS590 auto-tuner can tune the antenna, thereby keeping the
> radio happy?
>
> For more info on the W8AMZ 80-meter half sloper, go to:
>
> http://www.w8amz.com/W8AMZ_SLOPERS_Page.html#80HS
>
>
> Thanks for everyone's patient elmering here.
>
> 73 from Tom Behler: KB8TYJ 

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