[TenTec] Antenna question

[Phil Sussman]

Hi Bob,

Thanks for the help. I have a guy with a rig on the 2nd floor using home made 
ladder line consisting of #12 wire spaced a 4in. Feedline runs perhaps 10 ft 
before it splits off (corner fed) into the loop.

No balun at all. Fed right off the ladder line. I suspect the length of the 
loop may have to be adjusted. Short of hanging line out of a second floor 
window, I don't have a clue how to add more feed line.

73 de Phil - N8PS

----------

Quoting Bob McGraw - K4TAX <RMcGraw at Blomand.net>:

> I would change the length of the feed line by 20 or so feet.  Either add or 
> take away.  I do hope the feed line is reasonably straight an if there is 
> any excess is not in a "coil" somewhere.
> 
> Also, are you using a 4:1 balun or a 1:1 balun?  And are these voltage 
> baluns or current baluns?  I find that 1:1 current baluns work better in 
> most cases unless one is feeding something like a folded dipole where the 
> impedance is close to 200 to 300 ohms.  In this case a 4:1 works better.
> 
> Based on what you describe, I suspect that you are using a 4:1 balun.  That 
> device doing it's job and presuming the load Z at the feed line at the 
> transmitter end is say 25 ohms then the 4:1 balun is making that look like 
> 6.25 ohms.  Most tuners have a  problem with this.  Therefore a 1:1 balun 
> would present a 25 ohm load to the tuner.  Much better.
> 
> 73
> Bob, K4TAX
> 
> 
> 
> 
> ----- Original Message ----- 
> From: "Phil Sussman" <psussman at pactor.com>
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Sent: Wednesday, January 21, 2009 7:15 PM
> Subject: [TenTec] Antenna question
> 
> 
> > This may be a bit off-topic - If so please forgive me:
> >
> >
> >
> > I'm working with a fellow who has problems loading an 80M loop antenna 
> > with
> > ladder line and a tuner. His antenna is about 380ft and I think that it's 
> > a bit
> > short. I borrowed my Nye-Viking and the best that I can achieve is 3 to 1 
> > match
> > at 3800 KHz.
> >
> > At that point the tuner is applying MINIMUM capacitance. That makes me 
> > think
> > that a longer antenna length is needed.
> >
> > As an aside 40m loads no better 2.5 to 1, but 30m loads up OK.
> >
> > If I take his balanced line and feed it as a long wire (one end 
> > unterminated)
> > the system loads up just fine on 40m and 80m, but it is obviously 
> > unbalanced.
> >
> > Any quick hints appreciated -- I'm not the best with HF antennas.
> >
> > PS. My 80m loop antenna is 420ft long and loads as balanced just fine.
> >
> > de Phil - N8PS
> >
> >
> >
> > _______________________________________________
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> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> > 
> 
> 
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