Topband: 160m Inverted L High SWR

Gary Smith Gary at ka1j.com
Wed Oct 2 16:30:40 EDT 2013


Bill,

I'm probably the least savant of those on the reflector. Really... 
But I have an inverted-L which is held up under the tallest tree I 
can find and I have 45-50 130' radials on the ground and I'm feeding 
it directly with a 50 ohm coax. The SWR is at best 1.83 but it works 
fine on 10M, 12m, 15M as well as 160. The antenna is I believe 129.6" 
long and if you're looking for lower SWR, you could put a vac 
variable at the base, in series which will allow you to tailor your 
options. I used to do that but decided I really didn't need an ideal 
SWR and removed the vac variable because it worked fine as is.

73,

Gary
KA1J
 
> 
> Good afternoon all, 
> I just finished installing a new Inverted L. The previous one was
> removed because 
> a tree fell across a set of guys on my tower, which had to be taken
> down. The new 
> Inverted L is strung up amongst a lot of tall (80 ft +) pine trees.
> The vert. section is 
> abt 55 ft & the rest is nearly flat horizontal. Total length is 130
> ft/6 in. I am using a 
> 4 wire c-poise abt 9 ft high of which none are directly under the
> horiz. section. 
> Each wire is abt 135 ft long. The min. SWR is abt 2.9:1 at 1833 khz.
> The SWR 
> curve is broad which looks odd to me. I am feeding it direct with a
> random length of 
> 50 ohm coax. For these tests, I am using a TS-440S, which reduces
> power at this 
> value of SWR (the internal tuner does not operate on 160). Normally,
> I would run 
> vintage xmtrs, which load up ok. I will try it tonight to see if it
> gets out of the yard. 
>   
> Any suggestions how I can get the SWR down below 2:1 so the TS-440S
> will work at 
> full power? I apologize if this subject has been discussed before.
> If so, please point 
> me towards that info. 
>   
> Many thanks for any comments....73 de Bil l K4JYS 
>  
> _________________
> Topband Reflector





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