| Index | Thread | Archive | Nov-2002 | Archive | Send |
 |
  |
 |
   |
|
  |
|
make up a box to do it. Just got to take the time to measure each band. Tony -----Original Message----- From: Guy Olinger, K2AV [mailto:k2av@contesting.com] Sent: Saturday, November 16, 2002 21:32 To: n2tk@arrl.net; force12talk@qth.com Subject: Re: [Force 12 Talk] Phasing a C31XR and C3SS If you really want to make it work, you might just change the offset phasing length by band. Need a nearby helper with a transmitter, and a two channel oscilloscope, so you can just see the phase difference. Although this won't work with a regular stackmatch, you can do a homemade box that you can bandswitch the phasing device, using a special cut for each band. 73, Guy. ----- Original Message ----- From: "N2TK" <tony.kaz@verizon.net> To: "'Guy Olinger, K2AV'" <k2av@contesting.com>; <force12talk@qth.com> Sent: Saturday, November 16, 2002 2:00 PM Subject: RE: [Force 12 Talk] Phasing a C31XR and C3SS > Tnx Guy for the info. I knew going into this that it was a possible shot in > the dark. But out of it I got some stacking gain on 10 and 20m. Plus, I can > point to two different directions on all 3 bands and have instant switching. > So, all is not bad. I just never expected that 15m would show such a > negative gain. If the stack on 15 was near as good as each antenna I would > have been satisfied. But, signals drop quite a bit when the 15's are phased. > > I sure miss my monobanders of several years ago. Life was simpler then. > Maybe some day I will have time and get someone here to help me with a > remote signal so I can check it out, the WX0B way. Would be interesting to > see how out of phase the 15's are. I am sure that with the 15m driven > element on the C3SS being fed with jumpers from the balun, compared to the > C31 having no direct connection on the 15m driven element (element is > shorted at its center) is causing the problem. > > 73 > Tony > N2TK > > -----Original Message----- > From: Guy Olinger, K2AV [mailto:k2av@contesting.com] > Sent: Saturday, November 16, 2002 13:06 > To: n2tk@arrl.net; force12talk@qth.com > Subject: Re: [Force 12 Talk] Phasing a C31XR and C3SS > > The reasons why the antennas may not co-phase predictably are > numerous. > > While the physical displacement is an issue, it is not the only one. > The behavior of the driver cell has to be modeled. It may deliver an > EFFECTIVE phase delay caused by the interaction of the close elements. > Remember you are not directly feeding the 15 meter driver, you are > indirectly exciting it with the 20 meter driver, and the effective > phase of the wave moving forward will be some equation of the response > of both of them taken together. > > The general word on any attempt to phase dissimilar antennas, > especially tribanders, is that it's a shot in the dark. Sometimes you > can, sometimes you can't. > > I don't have a C3SS model up (it's linear loaded) or I could just run > the numbers and tell you the phases as modeled. > > 73, Guy. > > > ----- Original Message ----- > From: "N2TK" <tony.kaz@verizon.net> > To: <force12talk@qth.com> > Sent: Saturday, November 16, 2002 10:13 AM > Subject: [Force 12 Talk] Phasing a C31XR and C3SS > > > > I have a C31XR at 82'. I have a C3SS at 41'. I have equal length > Buryflex > > going to both - 85'. I tried several iterations of adding coax to > the C3SS > > to see if I can get some gain on all 3 bands. Here is what I found > out for > > my situation. > > - With equal length coax I did not see any stack gain on any bands. > > - By adding the distance the driven elements that have the balun > attached of > > each antenna are from the center of the tower and multiply this by > the > > velocity factor of the coax, I get 62". I added a 62" piece of coax > to the > > C3SS. Now I see stacking gain on 10 and 20m - it varies from just > noticeable > > to 2 s-units. On 15m, there is negative gain when stacked- about 2-4 > > s-units. > > - Tried different lengths of coax added to the 62" piece. I used 4" > > increments up to a total of 82". 10m and 20m still showed some gain. > 15m > > just got worse. It seems the best gain was with a total length of > 66" of > > coax added to the C3SS. It was difficult to tell the difference > between 4" > > either way. Did a lot of running back and forth to the tower to > change coax > > jumpers. > > - I wonder if the reason 15m shows negative gain is because on the > C31 the > > feedpoint is shorted together and on the C3SS the feedpoint is > joined to the > > coax with jumpers? Don't know if there is an easy way to do > something > > different to help 15m? > > - I haven't tried something less than 62". Don't know if there is a > length > > that would benefit 15m. > > > > At least I improved 10 and 20m. This will now allow me to improve my > signal > > on 2 bands and also allow me to have the beams in two different > directions. > > Even though I don't have gain on 15m, I can have the beams in two > different > > directions to quickly switch directions. > > > > Tony > > N2TK > > > > > > > > > > -------------------------------------------- > > Force12Talk mailing list provided as a service by Force 12 Antennas, > Inc. > > Force12 Web Site: http://www.force12inc.com > > > > To Submit Message to the List: Force12Talk@qth.com > > To unsubscribe and view the Message Archive: see > http://qth.com/force12/list > > For problems with the list: contact n4zr@qth.com > > > > > > > -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com |
This Thread
|
This Author (Nov-2002)
|