[TowerTalk] Antennas for SO2R station

[Michael Tope]

Hi Jamie,

About 20 years ago, I helped build an SO2R setup at W6UE. At that time, 
we had mono band Yagi antennas for 10, 15, and 20 meters stacked on the 
same mast with ~7 to 10 feet spacing. We also had a 40 meter mono band 
Yagi on a separate tower. Marty N6VI built a really nice set of LMR-400 
stubs for us that we installed right where the coax lead from each Yagi 
connected to the common port of the Radio1/Radio2 select switch. We put 
ICE-419 bandpass filters between each transceiver and the corresponding 
Alpha 78 amplifier.

As with others who have shared similar experiences, you could receive on 
one radio without desense while transmitting with 1500 Watts on the 
other radio as long as you stayed off the harmonic of the transmitting 
radio. We used various radios in the setup. Initially we ran a TS950SDX 
alongside a TS940S. Later on we used a pair of FT1000MP MK V's. In some 
instances the radios were setup for SO2R at one operating position. In 
other cases, we split the setup into a pair of one radio operating 
positions for doing multi-operator efforts in the SS contest.

Consider adding a set of stub filters to augment your bandpass filters, 
especially if you plan on running an amplifier and the power handling 
capability of the bandpass filters dictates that they have to be placed 
at the input of the amplifier. I think both W2VJN and K9YC have written 
good stuff on how to configure the stubs correctly.

Good luck. It's a real hoot when you get it working right.

73, Mike W4EF.........................

On 3/1/2021 10:20 AM, WW3S wrote:
> I live on a small lot, 80x180, in a subdivision....I have a 50ft tower 
> with a 3L Steppir on it.....I had planned on putting another Steppir 
> 2L about 7 ft above the tribander.....BUT......my current SO2R setup 
> I'm using a Hytower as the second antenna.....the rigs are a 7610 and 
> 7300.....I have 5B4AGN bandpass filters on both rigs.....I'm already 
> having interference issues between the rigs now, so I think moving a 
> second antenna to the same mast is asking for more trouble. Just 
> wondering if anyone uses 2 antennas on the same mast for SO2R? Also, 
> is the 7300 maybe a problem? I heard that radio generates a lot of 
> phase noise on TX, not so good in SO2R applications. Anyway, planning 
> for some tower maintenance this summer, and looking for suggestions on 
> optimizing the station for SO2R....
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk