You dont have to lower them but you need to short them to ground to make them electrically invisible
On Fri, Oct 12, 2018, 6:07 PM Dick Green WC1M <[email protected]> wrote: > Interesting. This is not how I tuned my 40m 4-square, albeit with tubular > elements not slopers. > > Anyway, my understanding is that you disconnect all four elements from the > control box and measure at the feedpoint, not through the phasing lines. I > did it that way and had no trouble tuning the elements. I did, however, > tune them to a frequency that was something like 5% below the target > resonant frequency. I can't remember the exact frequencies now, but I think > I wanted the array resonant at 7.025 MHz, so I tuned them to about 6.700 > MHz. Might have been a little higher than that. > > I've not heard that you must lower the other elements to do the tuning. > Certainly a pain with nesting tubular elements. > > 73, Dick WC1M > > -----Original Message----- > From: Guy Olinger K2AV <[email protected]> > Sent: Thursday, October 11, 2018 11:29 PM > To: David Raymond <[email protected]> > Cc: [email protected]; terry burge <[email protected]>; TopBand List < > [email protected]> > Subject: Re: Topband: trying to tune up 80 meter 4-Square > > Essential point that might be missed: each one of the elements, one at a > time, must be tuned independently with the other three elements down. This > is the initial tuning. If when everything hooked up characteristics are OK > then you’re done. > > Finish initial tuning and it's *not* OK? To slide the ARRAY center freq up > or down, there are several methods: > > 1) Redo the initial one at a time tuning with an opposite-to-the-error > adjustment to the one at a time tuning target frequency. > > 2) make *small* identical wire length changes to all four elements at the > same time. > > 3) If you're an engineer and have the equipment and design software, > redesign the box to work with what you have. ☺ > > Just remember that the elements of a four square are very heavily coupled > to each other, regardless that all are driven from the control box. The > final result is a complex function of the driven current AND the effects of > the heavy mutual coupling between elements. > > 73, and good luck, > > Guy K2AV > > > > > On Thu, Oct 11, 2018 at 8:15 PM <[email protected]> wrote: > > > Yes, install ONE sloper. . .measure and cut to resonance. Duplicate that > > measurement for the other three. 73. . .Dave, W0FLS > > > > -----Original Message----- > > From: Wayne Kline > > Sent: Thursday, October 11, 2018 6:03 PM > > To: terry burge ; [email protected] > > Subject: Re: Topband: trying to tune up 80 meter 4-Square > > > > Terry, > > > > > > > > I assume you only installed ONE sloper and made your measurements ? > > > > > > > > With all 4 installed there is way to much mutual coupling to get a > > meaningful reading. > > > > > > > > If your readings were from only ONE antenna tuned with a length of 50 > > OHM cable at it’s feed point and trimmed to your desired freq. and > > that FREQ will rise about 80 to 120 KC when the 4 are installed . > > > > > > > > Wayne W3EA > > > > > > > > Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for > > Windows > > 10 > > > > > > > > ________________________________ > > From: Topband <[email protected]> on behalf of terry > > burge <[email protected]> > > Sent: Thursday, October 11, 2018 6:11:37 PM > > To: [email protected]; terry burge > > Subject: Topband: trying to tune up 80 meter 4-Square > > > > Hello Guys and Gals, > > > > > > Recently Tree did some work for me and one of the things was to put up > > the Comtek 80 meter 4-Square switching unit and a couple of pulley > > setups for my raising of the 80 meter slopers. Lately I've been > > chasing my tail around to get them dipped in around 3700-3750 Khz. > > Been adding or subtracting length of the slopers to bring them into > > resonance but it seems the more I work at it the worse things get. > > Today I dropped back to punt by rechecking my Rig Experts AA-170 with > > a 50 ohm load just to make sure it read right...it did. > > > > > > The sloper dipoles are MFJ 1779B's 'trim to length' except one I had > > to rebuild with a hy-que center SO-239. RG-213 from the switching unit > > to the Rig Expert and when put together using a long run of LMR-400 > > about 175-200' > > back to the shack. 75 ohm DXE foam RG-11/u coax quarter wavelength > > stubs from switching unit to each dipole center. Each 75 ohm stub has > > multiple ferrite snap on's 5 or 6 to form current baluns. > > > > > > Here is an example. SE sloper, read SWR of 3875-3850 Khz of 1.0:1 in > > the shack on Elecraft W2 wattmeter. 3799 Khz SWR 1.3, 3775 Khz 1.4, > > 3750 1.5, > > 3725 1.5, 3700-3650 1.7...Added 19" each end and it seemed to read > > close to the same resonance! Added 24" more each end and this time > > used the Rig Experts to check it out. Got two dips but not even where > > I was expecting them > > > > > > Resonacne 4680 Khz SWR 1.16 > > > > RL 23.3 dB |Z| 57.4 ohm > > > > R: 57.5 ohms X: 10.7 ohm > > > > C: 52000 nF up and down > > > > > > R:: 57.9 ohm XLL -4878 ohm > > > > > > second dip at 2169 Khz SWR 1.07 > > > > RL 28.0 dB |Z| 46.5 ohms > > > > R: 46.5 ohms x: 0.2/0.4 ohms > > > > L: 2.2 nH > > > > R:: 46.4 ohm X|| (infinity or very high) > > > > L:|| same infinity > > > > > > And the frequency where I was trying to drop down from when I begain > > this morning.... > > > > > > 3860 Khz > > > > resonance now 3984 Khz SWR 1.8:1 > > > > R: 10.9 dB |Z| 27.9 ohms > > > > R: 27.9 ohms x: -0.1 > > > > c: infinity > > > > R|| 27.8 ohms X|| -48000 up and down > > > > C|| 8pF > > > > > > How can I add almost 4' of wire on each end and not drop the resonance > > down a couple hundred Khz? What is with the two dips way above and > > below where the 128' sloper should be resonating? That is an > > approximate length since by this time and several days of adjusting > > I'm not sure what each dipoles length are. Since I have a 40 meter > > dipole near the slopers I tried raising and lowering about 10-15' up > > and down but it did not seem to change much. > > I'm beginning to instinctively cringe each time I have to tune up an > > antenna because this is what I know I'm in for. Especially with > > dipoles! > > > > > > After all this I just made another run of the SWR across the band with > > the SE sloper. > > > > 3550 Khz 1.7:1 , 3600 Khz 1.7 , 3650 2.0 , 3700 1.7 , 3750 1.7 > , > > 3795 1.5 , 3825 1.3 , > > > > > > 3850 1.1 , 3875 1.0 , 3900 1.1 , 3925 1.3 , 3950 1.5 …..see > > what I mean? > > > > > > Terry > > > > KI7M > > > > > > > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
