Topband: 160 sloper readings

[Jeff Blaine]

Unless you have no BC stations for 200 miles distant, making 
measurements with an MFJ259 on 160m is going to give you unreliable 
readings.  The overload threshold on that band is extreemly low.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

On 18-Aug-18 6:10 PM, Gary Smith wrote:
> Folks,
>
> I'm starting to get ready for the upcoming
> winter frolics on 160. The 160 antenna is
> a sloper and I have somewhere around 50 or
> so 130' radials pretty much buried under
> 6-7 years of leaves. When I went to the
> remote coax switch & checked the readings
> on the sloper with 10' of coax, I found
> some readings with the old MFJ-259B that
> concerns me.
>
> I thought I'd cut the Sloper at 129' long
> for best SWR at 1.825 but I'm now reading
> the lowest SWR at 1.737 MHz and the
> impedance read 85. Going back to the shack
> I read the antenna (with 360' of 7/8 50
> ohm commscope now in-between), and the
> resistance drops to 55 but the SWR still
> reads lowest around 1.737
>
> It appears I need to shorten my antenna,
> I'll have to work out the proper length
> again but my concern is why at the feed
> point would I see 85 for the resistance at
> resonance.
>
> Suggestions on what might I give a look to
> when I go back out tomorrow?
>
> Thanks & 73,
>
> Gary
> KA1J
>
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