[TowerTalk] Fw: Looking for thoughts

Rod Greene w7zrc at yahoo.com
Tue Aug 7 10:20:27 PDT 2012


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. 


Rod/w7zrc



________________________________
 From: Gene Fuller <w2lu at rochester.rr.com>
To: towertalk at contesting.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" <w2lu at rochester.rr.com>
To: "K8RI" <K8RI-on-TowerTalk at 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 at tm.net>
> To: <towertalk at contesting.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.
>>
>> 73
>>
>> Roger (K8RI)
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
> 

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