Just came across an interesting picture re the TH11 question
Slide 66 of
https://wwrof.org/wp-content/uploads/2016/03/WWROF-WEBNAIR-RX-Antennas-for-a-Small-Lot-.pdf
A horizontal Waller Flag with interlaced 6m beam above a TH11! That is
A LOT of 6061!
Grant KZ1W
On 1/8/2022 08:35, Grant Saviers wrote:
My experience with a DB36 and 80 shorty dipole cause me to believe that
linear loaded yagis can be significantly affected by other antennas on
the same mast. My dipole was both element aligned and boom aligned at
11 ft separation and significantly disturbed the DB36 on 30 and 40m. 20
> 6 there is very little interaction.
Off course every antenna combination will be different. JK antennas
advertises for a couple models that they are not sensitive to others.
Modeling is a way to get an answer, more difficult with trapped antennas
when the trap models might be hard to find. Then the question is what
interaction and how much of it (G, F/R, F/S, SWR) is acceptable? My
modeling experience is that a good swr doesn't tell you much about the
other three, but a bad swr means something is amiss in them.
Some no/low interaction counter examples also exist - my 4L steppir with
add on 6m elements on the same boom. Because of almost 2x the height
for my 4L, with the add ons, performs essentially as well as a 6m M2
6M5XHP 5 over 5 stack at 38/53ft. So with some hard work and luck re
where elements can be placed it is conceivable a 6m 5 element could be
interlaced on a TH11. Separate feedlines make such designs easier. The
3 and 5 band no trap interlaced beams are awesome engineering works of
art IMO, having tried modeling of a couple of them I'd like to build.
Also, the more separation likely the lower the interaction. The VHF
literature has much to say about stacking re capture area. As a
practical matter, plot the swr for each HF band before and after putting
up the 6m. Then worry or not. The wind load from either is low so your
tower may allow a mast extension.
Grant KZ1W
On 1/8/2022 07:27, mike stokes wrote:
I have the same question except that I want to use a 5 Ele 6 and a TH11.
I appreciate thoughts for both Pete and my questions.
73
Mike
KK9V
On Sat, Jan 8, 2022 at 10:09 AM Pete Smith N4ZR <pete.n4zr@gmail.com>
wrote:
I have just bought a 3-element 6-meter yagi (Cushcraft), and plan to
mount it above a C-3E tribander. Would a quarter wave spacing above the
tribander be sufficient (5 feet), or do I need more? I'll likely just
have one convenient shot at this when I have the rocket launcher down
this spring, and I'd like to get it right from the start
--
73, Pete N4ZR
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