Re: [TowerTalk] 80m Newbie...Help w/ Inverted V Please

[Ted KT1V <kt1vbulk@demop.com>]

I had a 160m inverted V which due to trees etc. had one leg very close to a 
guy wire. No matter what I did, the SWR min was about 4:1.
I suspect coupling to the guy wire, but importantly IT WORKED OK. I worked 
plenty of DX with my 4:1 SWR and friendly ACOM amp which was happy to still 
put put a KW or so.

As a side note on 80m, my first 80m ant was an inverted Vee at about 30 
feet. Working EU was close to impossible. I raised it to 40 feet and EU was 
very very easy to work (obviously from the East Coast - hi!)

73
Ted KT1V
Ted Demopoulos KT1V
Demopoulos Associates, www.demop.com
Aligning Information Technology with Business Objectives.




Robin Midgett wrote:
>
> Hi,
> My attempts to make an inverted V resonate on 80m are not meeting with
> great success. I've put up inverted V antennas before (10m & 40m) and they
> worked very well...not so in this case; 2.8:1 (feed point fully up) is the
> best match I've seen yet. I'm hoping some of you more experienced will have
> some constructive input.
> Here's the configuration:
> 130' of Rohn 45G, on fairly flat, level ground with a 24" (out from the
> tower) aluminum stand off bracket at the 60' level. A rope and pulley rig
> is used at the end of the stand off to haul the feed point of the V up to
> the 60' level.  Each leg of the V is ~62' long, and there is ~ 80-90
> degrees between them. The ends of the wire (14 ga. stranded) are formed
> into a loop, which is where a small piece of rope attaches and anchors to a
> stake in the ground. Pretty typical stuff, from all I've seen before.
> The tower is guyed at 30' intervals to posts 85' from the tower base, so
> guy wire lengths (all 1/4" EHS) are 90', 104', 124' & 127', no insulators
> on any of them.
> With the feed point pulled up all the way, ~3:1 is the best match I get. If
> I lower the feed point to ~50', and the ends of the wires are drooped onto
> the lawn, the match improves to ~1.8-2:1.
> I'm using a MFJ-269 to make the measurements. I find really good matches
> (~1.5:1 or better) at 12 MHz, and odd multiples up the bands.
> I've changed the coax, no help. Removed the coiled coax choke; no help.
> Checked continuity from shield to end of one wire, OK; from center pin to
> end of the other wire, OK; no shorts, either.
> Is this possibly a case of guy wire coupling/interaction? Might raising the
> feed point to a higher level help the match? Should I extend the distance
> from the side of the tower to the feed point?
> Thanks,
> Lost in H.F....going back to VHF+....Robin KB4IDC
>
> "Success is the ability to go from failure to failure with no loss of
> enthusiasm." -Winston Churchill
>
> _

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