[TowerTalk] Upgrade

Drew Vonada-Smith drew at whisperingwoods.org
Wed Apr 25 14:36:38 EDT 2018


Consider the JK Mid-Tri/40.  You'll have less load, spend less, and have an antenna with the 40/15M interaction already worked out without the need for you to model it.  Performance will be similar, perhaps better if you consider 40M interactions.  Note that the 40M feedline is seperate, so SO2R etc is still workable.

If you do go with a separate 40M beam, please model your layout to assure good results.  Close stacking of Yagis has compromises.

The mechanicals on the JK antennas are beautiful.  I use the MidTri/40 with good results.  Reliable.

Two yagis on that sI'd say, pack will be a lot easier to deal with than three.  And you probably don't need quite the same monster to be effective on the WARC bands. Put that aluminum more into 20 & 15M.

Drew K3PA


Message: 10
Date: Tue, 24 Apr 2018 18:19:31 -0500
From: <kstover at ac0h.net>
To: <towertalk at contesting.com>
Subject: [TowerTalk] Upgrade
Message-ID: <003101d3dc22$b464cca0$1d2e65e0$@ac0h.net>
Content-Type: text/plain;charset="iso-8859-1"

OK Tower Talkers. I need wisdom and guidance.

I am finally in a position to start building my retirement station meaning a
BIG upgrade in the tower and antenna department.
Here is my plan.

70? AN Wireless HD tower
25? 3?x3/8 wall  4130 Chromoly mast, 20 foot out the top.
?? hard line from the man cave to the tower. I haven?t decided where to put
the coax switch yet, top or bottom.
Rotator, either a K7NV prop pitch or an Alpha Spid BIG RAK Anything with PST
in the name need not apply.

Antennas. I have to do all this on one tower.
Right now I?m leaning toward a JK Mid-Tri (20-10), a JK 1712 Jr for WARC .
and a 402T for 40m, in that order up the mast separated by 10ft.
16 sqft for the Mid-Tri, 9 sqft for the for the 17/12 Jr. 9sqft for the 402T
and 5 sqft for the mast. 
Another possibility is an Optibeam 11-5 for 20-10 WARC inclusive, the 402T
at the top then a six or seven element 6m beam in the middle

This load equals 39 sqft projected area including exposed mast. About 75% of
the tower rating at 100 mph. I live in an 80mph zone.
The mast will take the load all the way up to 125-130 mph depending on
antenna scenarios.

For the low bands I?m going to shunt feed the tower

SteppIR is not an option. They break too much. Save the anecdotes.
Same thing for PST whatever. They break too much. Save the anecdotes.

Since my disability my climbing days are pretty much over. I need to pick
products that are built hell bent for stout.
Nobody makes a crankup tower that will take that load. I could downsize the
antennas and go with a xr5-jk but it?s two elements per band on five bands,
I still haven?t figured out how the Navassa 5-jk works. 5 bands on a twelve
foot boom. Must be some ?Weird Science? (Quantum Mechanics) going on.

Thanks for the input.

R. Kevin Stover    AC0H


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