Also coiling up about 5 or so turns about 9 inches in diameter where the coax enters the shack can sometimes decrease shield RF getting into the shack.
73
David W Wood
Ham call - G3YXX
FOC # - 1685
Licensed - 1969
-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]] On Behalf Of Steve
Sent: Thursday, November 17, 2011 8:05 PM
To: [log in to unmask]
Subject: Re: SWR's continued
Tom,
If you coil up excess coax, it may act as an RF choke. If you wind five
turns or so, it is often referred to as a "poor man's balun". It is not a
bad idea to wind five turns or so at the connection to a beam or dipole, the
choke will help prevent some signal from radiating back along the skin or
shield of the coax, if there is a significant reactive load at the antenna.
I rather doubt that you derive any similar benefit with coiled coax at the
base station. However, it is pretty likely that if you cut out a hunk, you
will notice some change in your SWR. Remember though, the velocity factor
of typical coax is around 75% if I recall correctly.
Steve, K8SP
----- Original Message -----
From: "Tom Behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, November 16, 2011 9:47 PM
Subject: Re: SWR's continued
> John:
>
> My initial feeling here is that you might indeed be correct, but others on
> the list have a different opinion, when you consider the overall losses
> for
> 40 feet of RG8X on 160 meters.
>
> Actually, now, I don't know what to think.
>
> I guess I could just try it and see what happens, although I hate to go to
> all the trouble, not know ing for sure if it will help the situation.
>
> I'll continue to read the thoughts of any others on the list who might
> want
> to weigh in on this.
>
> 73 from Tom Behler: KB8TYJ
>
> ----- Original Message -----
> From: "John Miller" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, November 16, 2011 9:35 PM
> Subject: Re: SWR's continued
>
>
>> with 40 feet of coax coiled up, it's trying to radiate the coax, if you
>> cut
>> that section out, your readings and measurements will need to start over
>> again, but they'll make more sense.
>> ----- Original Message -----
>> From: "Tom Behler" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Wednesday, November 16, 2011 9:17 PM
>> Subject: SWR's continued
>>
>>
>>> Well, I took the LDG TW1 out of the circuit, and made a direct
>>> connection
>>> to
>>> the 160 meter sloper antenna.
>>>
>>> Lowest SWR according to the TS590 was 3.0 to 1--not as good at the TW1
>>> read
>>> with a 2.0 around 1.830 or 1.840, and when I went to the top of the
>>> band,
>>> the TS590 read "over" until I got down to around 1.900. The auto-tuner
>>> didn't tune the antenna up above 1.900 either.
>>>
>>> Why it tunes the antenna throughout the entire band with the TW1 in the
>>> circuit is beyond me at this point.
>>>
>>> Anyway, despite my efforts to shorten the thing about 9 or 10 feet, the
>>> antenna still seems a bit long to me.
>>>
>>> 73 from Tom Behler: KB8TYJ
>>
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