[TowerTalk] steppir v. lpda

[F.R. Ashley]

Am I going to work something on a SteppIR that I can't work on a LP?  Or a 
TH7?
Don't think so.

73 Buddy WB4M
----- Original Message ----- 
From: "Steve, W3AHL" <w3ahl at att.net>
To: "Tower and HF antenna construction topics." <towertalk at contesting.com>
Sent: Saturday, January 23, 2010 8:05 PM
Subject: Re: [TowerTalk] steppir v. lpda


> Since the Tennadynes that I've seen have a 50 ohm nominal feed point Z, 
> not
> 200 ohm, the issue is a little different.
>
> Having a balun at the front of the boom isn't a problem if it's 
> constructed
> correctly.  Using a coil of coax bundled up and flapping in the breeze 
> will
> eventually lead to failure probably.  A better solution is to use ferrite
> core balun is mounted in a weatherproof plastic box with its output
> terminals screwed into the boom / transmission line.
>
> Some Tennadyne owners do place the 1:1 balun at the mast plate and claim
> there is no significant difference in the pattern.
>
> What affect the feed line imbalance has in either case hasn't been evident
> in the few field measurements I've seen posted.  Whether it is enough to
> justify constructing a custom balanced feed line back to the mast is
> doubtful, if a couple of ferrites at the mast are effective.
>
> LPDA's that do use a 200-ohm transmission line boom usually have a feed
> point Z of 95-110 ohms.
>
> Steve, W3AHL
>
> ----- Original Message ----- 
> From: "Gene Fuller" <w2lu at rochester.rr.com>
> To: "Tower and HF antenna construction topics." <towertalk at contesting.com>
> Sent: Saturday, January 23, 2010 4:23 PM
> Subject: Re: [TowerTalk] steppir v. lpda
>
>
>> For the umpteenth time,ehy not make up 200 ohm  line,using 1/4" copper
>> tubing, on standoffs to keep aay from the boom, placing the balun back at
>> the mast, where it is accessible.
> ..snip..
>
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