I have the book. It is among the first antenna books I bought in 78 when I was first starting in this hobby. The book is The Amateur Radio Vertical Antenna Handbook by Capt. Paul H. Lee, USN retired N6PL SK. I built one of the 1/2 over 1/4 wave that you gentlemen are talking about for 20m and it worked very well indeed. the sleeve I used was a cage of 8 wires for the middle 1/4 wave section which also gave the phase shift needed. It is not perfect because the sleeve diameter prevents a perfect shift, but a happy medium is possible and it will work.
73 es DX Pat H. Armstrong KF5YZ PS I have a son named Mike ---- Mike Armstrong <armst...@aol.com> wrote: > Hey...... IF the tower is tall enough for that duty (3/4 wave tall), then you > could put that "skirt" on the "middle" 1/4 wave, as it were, and you got > 'er...... Could he be that lucky? I have to admit, other than right this > second, I hadn't ever considered that as a possibility. It "should" work so > long as the height is close to correct and whatever is mounted to the top,of > the tower doesn't make the structure look too,much larger than it should look > for resonance. > > HMMMMMMMM > > Mike AB7ZU > > Kuhi no ka lima, hele no ka maka > > On Sep 6, 2013, at 19:58, "Charlie Cunningham" <charlie-cunning...@nc.rr.com> > wrote: > > > Hi, Mike > > > > I remember the guy that you are referring to, but it's been so many years > > that I don't remember his last name tither. He published a book via either > > ARRL or CQ mag. > > > > A collinear 1/2 wave over a 1/4 wave GP has certainly been done and used > > commercially at VHF. The "skirt" can also be replaced with a shorted 1/4 > > wave phasing line. > > > > Well, Tom's tower is probably tall enough - but how in heck would we get the > > verticals far enough away from the tower?? > > > > Charlie, K4OTV > > > > -----Original Message----- > > From: Mike Armstrong [mailto:armst...@aol.com] > > Sent: Friday, September 06, 2013 10:42 PM > > To: Charlie Cunningham > > Cc: ZR; Shoppa, Tim; <topband@contesting.com> > > Subject: Re: Topband: Are stacked verticals feasible? > > > > Carl and Charlie, > > I am not sure it would even be close to practical or even doable, but I > > remember seeing an old book on verticals written by a prior Navy Captain, I > > believe. He had a very interesting design for what WE would, today, call a > > collinear that was 3/4 wave length tall on 20 meters..... it was, in reality > > what looked like half of a double-zepp antenna in a vertical orientation. It > > intrigued me that it was like a half wave stacked on top of a 1/4 wave > > worked against ground (normal radial field). The interesting part was how he > > used a "skirt" around the "middle" quarter wavelength portion to produce the > > the in-phase relationship with the physically lower 1/4 wave. > > > > You guys may already know the design I am talking about. I saw that book a > > long time ago, like back in the late 60's I think..... maybe early 70's. I > > was considering trying to find the article or book whenI was looking for a > > better vertical for my winlink node on 20 meters..... the one I have been > > talking about. However, I tried the 5/8ths first because I knew how to > > build one without having to possess any special instructions. It was so > > successful, that I completely forgot about the "collinear." On the other > > hand, this discussion reminded me of that book and how author "raved", a > > little anyway, over its performance. I remember that the height of the > > finished antenna for 20 meters was something very close to 50 feet...... and > > that is not much taller than a 5/8ths..... maybe 7 or 8 feet taller. So on > > 20 it is very doable and, supposedly, it has some reasonable gain for the > > effort. I would like to find the book because it described a good way to > > make that all-important skirt that got the phase correct between the upper > > half-wave and the lower quarter-wave sections. Due to its relatively tall > > structure, it probably wouldn't even be "possible" to build one for 160..... > > at least not by most of us. It would be interesting to see if it has the > > same "problem" that Tom was referring to for the 5/8ths..... "too low" > > radiation angle. I know it isn't supposed to have that secondary lobe that > > a 5/8ths has...... So maybe it would be an improvement ..... IF it was even > > possible to build one. That would be one tall structure on 160.... LOL LOL. > > Still, for someone needing an omni antenna with some gain on the higher HF > > bands, it might be a decent answer. Never built one, so I really don't know > > if it really works or not. Although, as I said, that author was a Navy > > Captain whose job was designing some of the shipboard antenna systems, like > > the NORD and some other odd ducks.... Well, "odd" to those who don't have to > > build low loss, low band antennas on a floating "postage stamp." I know, I > > know, you might have trouble thinking of something the size of an Aircraft > > Carrier being referred to as a floating postage stamp, but if you have spent > > any time at sea on a "big deck," you know exactly what I mean by that > > statement...... he he he he. I really should remember his name, darn > > it..... with all the time I spent on ships at sea working with his designs, > > it is really sad (bad?) that I don't remember his name...... Paul > > "something?" I'll find out..... lol > > > > Mike AB7ZU > > > > Kuhi no ka lima, hele no ka maka > > > > On Sep 6, 2013, at 19:03, "Charlie Cunningham" > > <charlie-cunning...@nc.rr.com> wrote: > > > >> Well, Carl > >> > >> You just proposed a total height of 3/4 wavelength, it seems. Do you have > >> that much height? > >> > >> Charlie, K4OTV > >> > >> -----Original Message----- > >> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of ZR > >> Sent: Friday, September 06, 2013 9:26 AM > >> To: Shoppa, Tim; topband@contesting.com > >> Subject: Re: Topband: Are stacked verticals feasible? > >> > >> Look at it as 2 ground planes with the lower feed point 1/4 wave above > >> ground along with its elevated radials which should make it pretty much > >> ground independent according to what has been published on here and > >> elsewhere. > >> > >> The second ground plane would be identical with 1/4 wave spacing from the > >> top of the lower antenna or a 1/2 wave between feed points. > >> > >> Then I would think that the ground conductivity at the reflection point > >> would be the only concern as far as efficiency and gain?? > >> > >> If installed as vertical dipoles then there would also have to be > > additional > >> spacing between them. > >> > >> I would think that at 6-12' spacing from the tower it would minimize > >> interaction on 160 or 80? > >> > >> Does anyone on here have EZNEC and can plot this? > >> > >> Carl > >> KM1H > >> > >> > >> > >> ----- Original Message ----- > >> From: "Shoppa, Tim" <tsho...@wmata.com> > >> To: "Carl" <k...@jeremy.mv.com>; <topband@contesting.com> > >> Sent: Thursday, September 05, 2013 10:30 PM > >> Subject: Re: Topband: Are stacked verticals feasible? > >> > >> > >>> Isn't this a "Vertical dipole"? Two quarter wave radiating elements? And > >> tower behind it will be some kind of reflector/director depending on > > height. > >> The radials seem unimportant if thought of this way. > >>> > >>> Tim N3QE > >>> ________________________________________ > >>> From: Topband [topband-boun...@contesting.com] on behalf of Carl > >> [k...@jeremy.mv.com] > >>> Sent: Thursday, September 05, 2013 9:17 AM > >>> To: topband > >>> Subject: Topband: Are stacked verticals feasible? > >>> > >>> Assuming that sufficient tower height was available, guy wires are > >> insulated > >>> or broken up into short non-resonant sections. Tower face is 12 or 18". > >>> > >>> Start at 1/4 wave up with a 1/4 wave ground plane with radials sloping at > >>> about 45 degrees. The vertical wire is 6-12' away from the tower face. > >>> > >>> Then a 1/4 wave (or 1/8) up install a duplicate. > >>> > >>> What does EZNEC say about this? > >>> > >>> With the different spacings? > >>> > >>> Effect of starting lower and how low before there are ground related > >>> problems? > >>> > >>> Phasing with coax or a LC network? > >>> > >>> Switching in a delay line to tilt the lobe up a bit? > >>> > >>> Curiosity got the cat! > >>> > >>> Carl > >>> KM1H > >>> > >>> > >>> > >>> > >>> _________________ > >>> Topband Reflector > >>> _________________ > >>> Topband Reflector > >>> > >>> > >>> ----- > >>> No virus found in this message. > >>> Checked by AVG - www.avg.com > >>> Version: 10.0.1432 / Virus Database: 3222/6141 - Release Date: 09/05/13 > >> _________________ > >> Topband Reflector > >> > >> _________________ > >> Topband Reflector > > > _________________ > Topband Reflector _________________ Topband Reflector