Good morning all,
Thought I would throw in my setup FYI. I have an approximately 50' tower with a
little tribander (A3S) and 40m dipole (KLM single el) on top. I have installed
three slopers from the top spaced fairly equally around the tower. They are
each approx. 72' long and are angled at (again approx) 45 deg. to the tower. I
also have an SGC-230 auto tuner at the tower top then a DX-Engineering remote
switch to select one of the three. That way I can use the slopers on all bands
and auto tune as needed. I get some pattern on 20m and up. It works pretty well
as a second/backup antenna to the others.
From: Gene Fuller <email@example.com>
Sent: Tuesday, August 7, 2012 10:49 AM
Subject: [TowerTalk] Fw: Looking for thoughts
I sent this to Roger a couple of days ago,but judging from the other
replies, I'll forward to the group.
Gene / W2LU
----- Original Message -----
From: "Gene Fuller" <firstname.lastname@example.org>
To: "K8RI" <K8RI-on-TowerTalk@tm.net>
Sent: Monday, August 06, 2012 11:28 PM
Subject: Re: [TowerTalk] Looking for thoughts
> Hi Roger -
> Sounds like a good project. I have three 160 quarterwave slopers which
> also act somewhat as 80 meter reflectors for my 80 meter bent vertical
> dipole array. I use SPST relays to connect one sloper at a time to an
> RG-213 cable which goes to the base of the 100 foot tower. At the base I
> have a simple L network which matches the RG-213 to a 200 foot cable TV
> 75 ohm burial cable back to the station. Being on 160 there isn't too much
> SWR loss in the cable down the tower and it is relatively convenient to
> come up with an L network which results in an easy cable to work with back
> at the station.
> Points which led me to this:
> 1. Relatively small loss, at moderate SWR, in the RG-213 at 1.8 MHz.
> Selected the sloper length as good for an 80 meter reflector, not minimum
> SWR on 160.
> 2. Relative ease of applying and maintaining a matching network at the
> base of the tower.
> 3. I had all of the material on hand. Maybe only 3 or 4 db "F/B" between
> the three slopers on 160, but I love the idea of 3 KW ERP vs 1.5 KW. Guys
> who settle for a single sloper because "there's only 4 or 5 db F/B are
> failing to appreciate the relative gain aspect of the configuration.
> Good luck with your endeavors.
> Gene / W2LU
> ----- Original Message -----
> From: "K8RI" <K8RI-on-TowerTalk@tm.net>
> To: <email@example.com>
> Sent: Monday, August 06, 2012 4:49 PM
> Subject: [TowerTalk] Looking for thoughts
>> I'm thinking of mounting a tuner up on the tower to feed the 160 half
>> sloper (single wire) as well as the 75 meter fan dipole and 40 meter
>> sloping dipole with ladder line, so I'll need to add a few relays to
>> switch antennas.
>> This can be a simple manual tuner, remotely driven with air variables
>> and a switched inductor, or vacuum variable and a rotary inductor, or
>> even one of the MFJ 998RT auto tuners. If I build it, I'd much prefer a
>> tuner that handles single and parallel wire without using a balun
>> Unfortunately the 998RT only has a single wire and coax output. I can
>> work around that and *apparently*, or at least some think it'd handle
>> all the way up to 2500 PEP.
>> Of course there is the problem with lightning and remote tuners mounted
>> at or near the top of the tower. Grounding relays could be added.
>> Roger (K8RI)
>> TowerTalk mailing list
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