http://elecraft.85.s1.nabble.com/Balun-at-input-or-output-of-tuner-tp7087668p7103112.html
Thanks for the tip on the AV-640...I'll surely look into that. I am looking for a self-supporting solution to minimize my impact upon the XYL's view (to her credit, she's been incredibly patient and understanding about that). The home brew vertical dipole I'm running now requires guys which isn't pretty in her opinion.
You're right about my not having space for horizontal antennas. I had shoe-horned in here an inverted-vee for a while, but that was little more than a cloud warmer -- my vertical dipole out-performs it 10 to 1.
I went with the vertical dipole because I'm leery of verticals without radials...I see the AV-640 has what appears to be a ground plane, so that may work out just fine.
I have been reading your papers and am beginning to have a fair understanding of the pin 1 problem, though I admit I have not gotten very far in physically implementing it. I do notice the amount of RF in the shack varies a lot if I mess around with the position the 450-ohm window line. That's what piqued my interest when I read about the use of a CM choke at the feed point of balanced lines...If that helped to restore balance in the balanced feeder, my thought was that might reduce feed line radiation enough to make my relatively minor RF-in-the-shack problem effectively go away. And if it improved my radiation pattern in the process, so much the better.
But I am seeing now that line of thinking was a bit simplistic and the issue is bigger than that.
Jim, thanks for the response to my post and for sharing your knowledge in general...I for one appreciate it.
> On 12/13/2011 12:53 PM, David Herring wrote:
>> I'd like to ask a few questions.
>
> David,
>
> I hardly know where to begin in responding to your question. First, if
> you want a self-supporting vertical antenna for 30-10M, there are some
> really good choices that you can buy, that can be easily installed, that
> can be fed with 50 ohm coax, that don't require radials, and that don't
> require a balanced tuner. Loss in the feedline should be quite small if
> you use RG8 (or even RG8X). Look at the Hy-Gain AV-640, which one of my
> friends has used to work a lot of DX and do contesting from a small city
> lot. You should use one of my chokes at the feedpoint of this antenna.
> See my RFI tutorial, previously referenced.
>
> IMO, balanced tuners and so-called balanced line are highly over-rated
> solutions to problems that don't exist, or that could be better solved
> with other far simpler and less costly means. IMO, the only GOOD use of
> high impedance parallel wire feedlines is for very long runs -- 500 ft
> or more. Likewise, I am not a fan of all-band non-resonant dipole
> antennas, primarily because it is mechanically difficult choke them at
> their feedpoint, which makes them noisy and puts RF on the feedline, but
> also because their directional patterns vary widely with frequency.
> Since you're trying to make a vertical work on all bands, I'm assuming
> that horizontal antennas are not practical for you, hence the
> recommendation for the AV-640. I'm not a fan of compact, multi-band
> verticals below 40M because their efficiency tends to be poor, but at
> 30M and above they can work quite well.
>
> As to RF in the shack -- nearly all RF in the shack problems are the
> result of Pin One Problems in equipment. See the RFI tutorial for an
> explanation and solutions. Also see the pdf on Ham Interfacing for
> detailed instructions about bonding all of your gear together with short
> lengths of copper wire. This kills hum and buzz, and makes a big dent in
> the RFI you're experiencing. In extreme cases you may need to add
> chokes to individual cables.
>
>
http://audiosystemsgroup.com/publish.htm>
> 73, Jim K9YC
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