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[Towertalk] tnx info, Greenlee & 80M vert.

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Subject: [Towertalk] tnx info, Greenlee & 80M vert.
Date: Fri, 17 Jan 2003 16:12:01 +0000
It's been less than 24 hours but I already have good suggestions on both my 
questions.  Here's a summary, some of which went just to me and not to the 

1.  I realized myself I could ease the Greenlee hanging chad problem by 
using a larger drill bit for the pilot hole.  Then the chad would be less 
likely to bind not only in the cup where it, by definition, is going to be 
an exact fit, but also to the screw in the middle.  With a larger pilot hole 
it would only be binding on the outside.  This occurred to me after 
launching the towertalk question.

2.  I like the idea of using WD-40 on the punch beforehand.  I have noticed 
they have a definite tendency to rust.

3.  On the various ideas of prying and knocking the chad out, I will be 
trying those.

4.  On the 80M vertical, some have reported 2:1 SWR bandwidth of 60-80 kHz.  
I suspect those are on shortened antennas.  K4JA and K2YWE and maybe one or 
two others report over 300 kHz 2:1 SWR bandwidth -- K4JA's with a fullsize 
four-square.  The broad bandwidth seems due to larger diameter radiators.  A 
four-square may have a larger diameter radiator effect by virtue of being 
four radiators rather than just one, plus K4JA's and many others use tubing 
or tower as the radiators themselves.  K2AV had a nice chart of bandwidth to 
be expected with various diameter radiators.

5.  Many suggested more than two radials will increase efficiency with a 
corresponding decrease in SWR bandwidth, that my bandwidth may be due to 
needing more radials for better performance.  I may try this, despite the 
Dayton Antenna Forum presentation a few years ago that said even just one 
radial was enough and many very successful stations using just one or two 
radials, when the radiator is elevated.  This strikes me as analogous to the 
quad v. yagi debate and each side quotes scientific evidence to prove their 
point.  I think it is undisputed that more radials are better when the 
vertical is ground mounted.  There also seems to be at least a consensus 
that elevating the feedpoint of your vertical is good and that fewer radials 
are needed (e.g. N4KG's 10 and other peoples' 4) to equal the performance 
with 120 radials on a ground-mounted vertical.  The debate comes down to 
just how few radials on an elevated radiator will equal or come close to 120 
ground mounted radial performance.

Thank you all for your helpful comments and suggestions!  CU on 80.
Next, pruning, maybe more radials, run the coax the rest of the way to the 
house, contemplate hooking up CATV hardline that's already run most of the 
way instead of RG-213 that I'll almost certainly hook up between the antenna 
and shack first to have some fun with it and check it out, and some 
beverages for receive.  Then, get a 160M antenna up and tribander or 
40-through-10-bander to get on all the bands.

73 - Rich, KE3Q

Rich Boyd


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