Modeling of Milt N5IA 160 8 circle with his 80M 4SQ out side showed same thing - need to leave the 80 M elements open
Hank K7HP ----- On Jan 28, 2020, at 9:43 AM, Mpridesti via Topband <[email protected]> wrote: | I had heard several negative mentions of placing an 80 m system inside a 160 m 4 | square. At my place, I placed my 80 m 4 SQ northeast of my 160 m 4 SQ. Closest | elements are 75 feet away. Thinking I might get some negative interaction, I | took K3LR’s suggest of opening the feed points of the 80 m array while I am | using 160. Built a relay box that shorted the cable ends (1/4 wave 75 ohm | lines) so electrically opened the feed points. Pretty simple. | Then spent a lot of time listening to WebSDR receivers in EU and switched that | relay box on/off to see if I saw any gain variation with the 160 antenna. I saw | no difference. However I have found a very slight improvement in F/B or F/S | when the 80 m array was open circuited (shorting relays engaged). | On the flip side of this, I have not seen any impact on 80 to the SW as I beam | through the 160 array. I have reference antennas on each band to check array | performance. | I continue to experiment on 160 - fun retirement project with lots of exercise! | Seems array interaction varies with different stations. I did not model my | setup. | Regards, | Mark, K1RX | > On Jan 28, 2020, at 10:47 AM, Tree <[email protected]> wrote: | > W7IV asks: | > " --I am planning a 160m TX 4SQ and another for 80M. Their centers are | > going to be about 300' apart - is this far enough away? I have a little | > bit of room to move them apart, but am lucky enough as it is to have the | > space to get this. The closest verticals will be about 200' apart." | > My experience supports the post K9YC just made that you don't need to worry | > about this. | > I used to have an 80 meter 4 square with my 160 meter TX antenna right in | > the middle of it and | > everything worked great. You can also see this in the ON4UN antenna | > system. | > 73 Tree N6TR | >> On Tue, Jan 28, 2020 at 12:33 AM Paul F. Merrill <[email protected]> | >> wrote: | >> HI - I have a couple questions - | >> --I am planning a 160m TX 4SQ and another for 80M. Their centers are | >> going to be about 300' apart - is this far enough away? I have a little | >> bit of room to move them apart, but am lucky enough as it is to have the | >> space to get this. The closest verticals will be about 200' apart. | >> --I'll be using N6BT vertical dipoles, so there will be no radial issues. | >> --WRT TX chokes - I'm worried about constructing feedline chokes for the | >> feedpoints and still having enough cable (.85vf) to get to the phasing | >> box. How have others done this? Do you have a choke and did you add it to | >> pre-cut phasing lines or did you wind the chokes and work backwards towards | >> the center to get the required electrical or physical length? Did you used | >> magnet wire for the choke instead of coax? | >> I've come across N6RO's helpful 2017 writeup of his 4SQ refurbishment and | >> it touches on these issues. Anyone else have time to share some wisdom? | >> Thanks in advance, Paul / W7IV | >> _________________ | >> Searchable Archives: http://www.contesting.com/_topband - Topband | >> Reflector | > _________________ | > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector | _________________ | Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
