Sorry I haven't commented sooner, but was away for a few days, busy with
other things, etc. I've been fairly successful with single-tower SO2R.
For example, just received my plaque for First Place in ARRL DX CW 2007
W/VE and had several other wins in major contests over the last 5 years
or so.
My setup was as follows (recently downsized the station after a
lightning strike over the summer):
Radios: FT 1000D and FT990
Amps: 2 Acom 2000A's
Switching: Top Ten Devices Band decoders and sixways. 2 sixways to
switch antennas and another 2 to switch stubs. I also had a bunch of
homebew stuff involved in switching antennas between the 2 radios, Array
Solutions NQN bandpass filters and headphone audio (I wrote an article
in NCJ about 5 years ago on the audio switching.)
Antennas: Single 76 ft Rohn 45 tower with a Cushcraft 402CD at 85 ft, 2
phased TH7s @ 76 and 45 ft (using a DX Engineering (the old company)
phase box. A third TH7 was at 25 ft for the second radio. I modeled
phasing all 3 and the low one provided no significant gain to the 2
higher ones. On 80 I use a K8UR-style array and on 160 an inv vee (600
ft Bev for EU rcv), both hanging off the same tower. The top TH7 and
402CD were rotated with a T2X and the 2 lower TH7s with TIC Rings.
Regarding multiband verticals - stay away! I tried one when I first
went SO2R. It was mounted 10 ft off the ground, about 200 ft from the
tower. I believe it was a Hygain, or maybe a GAP, but it was
worthless. When I first put up the TH7 at 25 ft, the vertical was still
up for comparison - there was regularly a 6 S-unit difference on
20-10m!!! I never used it on the low bands as there was no need.
Regarding isolation between radios, with the stubs and NQN filters, I
had no problems unless I was within 10 KHz of a second harmonic. For
example, if I was on 7005, there would be a l9oud signal on 14010,
pretty much preventing me from hearing 14000-14020. However, I could
work higher on 20m no problem - and my 40m antenna was only 10 ft from
my 20m antenna! There were no interference problems whatsoever if not a
direct second harmonic (eg., 20 and 15 together, 15 and 10, etc.) One
cheap, but important thing - when cabling the station, use coax with
100% shield - it really makes a difference. For the low power cables
(between radios, NQN filters and amps) I used LMR240. On the output
side of the amp (to stubs and antennas) I used LMR400.
Hope this helps...
73,
Barry W2UP
Lee Buller wrote:
> Wow....
>
> I've learned a lot about SO2R installations over the last week. Thanks for
> all the emails and responses. Now, here is another questions.....
>
> Antennas. I think I have an issue with antennas because of make up of my
> location. I have a 60 foot tower with a C3E - 80 and 40 meter inverted -V
> dipoles on separate feedlines but at the same height on the tower, a 160
> meter Inverted-L on the tower...and a full size quarter-wave vertical in the
> yard with 32 radials. I was planning on changing out the vertical for a
> Butternut 6 band model or something similar, but as I was looking at the
> installation the antenna would be very close to both the 160 -80- and 40
> meter antennas....less than 15 feet. I am on an 80 by 150 foot lot. (I
> think SO2R is gonna get expensive when I tell the YL we have to move!) So,
> is it worthwhile to even consider doing SO2R on such a small lot because of
> the proximity of the antennas. This is a considerable investment....minus
> the new farmstead.
>
> Lee - K0WA
> "Going to buy a Lottery Ticket...."
>
>
>
> In our day and age it seems that Common Sense is in short supply. If you
> don't have any Common Sense - get some Common Sense and use it. If you can't
> find any Common Sense, ask for help from somebody who has some Common Sense.
> Is Common Sense divine?
>
> _______________________________________________
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>
>
>
--
Barry Kutner, W2UP Newtown, PA
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