[SECC] ARRL SS 40m antenna that works!
Dan/W4NTI
w4nti@mindspring.com
Tue, 27 Nov 2001 18:38:06 -0600
What you have there is a turnstile, if you look in a VHF handbook you will
see it. But of course for higher bands.
I tried one of those way back when on 20 meters. But I had it in my attic
of all things. So it would be difficult to say how well it worked.
What you have done tho, is to refresh my memory and I think folks need to
look at the Nuker....it could be a useful antenna.
Dan/W4NTI
-----Original Message-----
From: n4uk@mindspring.com <n4uk@mindspring.com>
To: secc@contesting.com <secc@contesting.com>
Date: Tuesday, November 27, 2001 5:02 PM
Subject: [SECC] ARRL SS 40m antenna that works!
>Bill, SECC,
> I have pasted and copied a text file of an e-mail I sent to
the contest reflector around 1997/88 describing my secret SS weapon for 40
meters. You might want to consider it. Those that have tried this antenna
have been quite pleased with its performance for domestic contests! If I
ever find the time I might try the same version for 80 meters form
domestics.
>Ken, N4UK
>
>
>Hello to all!
>Are you interested in a kick ass Sweepstakes
>antenna that doesn't eat into your budget? Then read on OM!
>This project began with the thoughts of entering the ARRL
>Phone Sweepstakes for my first ever serious effort. I set some
>goals that I thought to be within reach. One of my goals was to
>win the division and try to break the Roanoke division SS Phone
>record held by W4MYA. Another goal was to be able to run
>stations who were using average,run of the mill high angle
>antennas on 40 meters. Sort of like high angle meets high angle!
>40 meters was to be my bread and butter band since I don't have
>any rotating antennas on any of the higher bands.
>After some careful thought I came up with a list of
>what I thought I needed to do for antennas in order to achieve
>my goals. Here is what I came up with:
>1- I needed a 40 meter antenna that performed well into the
>populated areas that were within daytime 40 meter range from my
>QTH here in NorthWest South Carolina. I.E. W2,W3,W5,and W8/9
>2- The 40m antenna needed a fairly high angle of radiation to
>"reach" into the 400-700 mile range with a loud signal.
>3- I needed to be loud in all those areas at ALL times and not
>only when the proper antenna was switched in line. Read this as
>Omnidirectional!(helps to hold the frequency too)
>4- I needed a 20m antenna that performed well to the NorthWest
>where I might have trouble on the low bands picking up those
>"remote" ARRL sections.
>I Put up a 2 el wire quad beaming NW for 20 meters and
>found it to be an admirable performer to the intended direction
>though I learned during the contest that the West RULES on 20
>during the Sweeps. Which returns us to the 40 meter antenna.
>The antenna I put up on 40 meters is so simple as to
>be laughable yet I cannot find any reference to it in any of my
>old or new antenna books nor have I found anyone who has ever
>tried one. It performed beyond my expectations and netted me
>nearly 1,100 qsos on that band during the phone SS. I would have
>had even more Qs if I had known earlier how well it was working
>which would have kept me from wasting time on 20 meters. The
>signals from w9/w8/w3/w2/w1/and w5 just kept rolling in and
>rolling in at all times of the day. I had no problem holding on
>to a run frequency for as long as I wanted it. At night I had an
>abundant supply of W0 and w6/w7 to work and still had w8,9 and
>w3 calling with loud signals . I dubbed this antenna "Project X"
>due to its configuration but now call it "The NUKer" because of
>its nice round, Mushroom Cloud pattern and the way it blanketed
>the intended target areas with RF. (not fallout)
>The Antenna-"This is NOT your Father's turnstile"
>The NUKer is 2 inverted Vees at 90 degree angles to each
>other both fed at the same point on the tower with apexes at 40
>feet with a T connector and a 1/4wl of 75 ohm line on one side
>of the T feeding one of the antennas. They form an X at the
>apexes albeit sloping downward. I used 50 ohm coax(80ft) to feed
>the center of the T connector and an ELECTRICAL 1/4 wavelength
>of Radio Shack bought RG59 for the phase line. RG6,RG11 or any
>other 75 ohm coax can be used. The Velocity factor of R.S. RG6
>and RG59 is stated as 78 percent. The 1/4 wl section was
>calculated as 234/7.1mhz x .078. The 75 ohm coax phase line was
>coiled up and taped to the tower at the feedpoint of the T
>connector. The 50 ohm "stub" of coax from one port of the T
>connector to the other inverted vee should be kept as short as
>possible. The stub I used is about a foot long. Both inverted
>vees are exactly the same length physically. The angles of the
>inverted vee legs are as close to 90 degrees as possible and the
>ends are about 10 feet off the ground. I installed one vee at a
>time and tuned it for resonance at 7.1 MHZ. I used Budwig HQ-1
>dipole center insulators which have an SO239 connector built in
>to them. This made it a snap to swap the feedline during the
>tuning process. After the lowest SWR was attained I put up the
>second Inverted vee at a 90 degree angle to the first one. The
>apex of the top vee is about 6 inches above the apex of the
>second vee. It too was then tuned for lowest swr using the same
>feedline as the first Vee. The T and the phasing line were
>installed, the 50 ohm feedline connected to the T and voila,a
>low swr across the band.
>This antenna has a flat swr from 6900-7400
>with a slight "bump" (increase) in swr at around 7080. The
>usable bandwidth practically doubled compared to a single
>inverted vee. An added bonus was a very low swr all across 15
>meters!(I can't vouch for its performance on 15 since I haven't
>had the time to test it much on that band) A little touching up
>may have to be done if the center isn't where you want it to be.
>Make sure both vees are increased or decreased equally in length
>when doing so.
>Computer modeling done after the Phone
>Sweepstakes (Thanks K3MM!) confirmed what I had hoped and what I
>discovered about this antenna during the Sweepstakes. It is
>perfectly Omnidirectional and exhibits a 3db gain over a
>dipole at an equal height! This is 3 db over the dipole towards
>the directions that a dipole favors. I am not sure how many DB a
>dipole is down at its ends but assuming it is down 10-15
>db vs. its optimum directions, the NUKer is then 13-18 DB better
>in the direction a dipole DOES NOT favor and you don't have the
>hassle of switching between antennas. What about nulling out qrm
>you say? I prefer to null out QRM using the brain filters.
>Besides, when you null out qrm you are also nulling out possible
>contacts in that direction too. QRM for me is the broadcast junk
>from Europe. This also is the highly populated Northeast
>corridor. I couldn't afford to null them out too.
>The A/O model also predicts maximum gain from
>60-90 degrees above the horizon. Those figures are perfect for
>my QTH for DOMESTIC contests. A single support, easy to
>construct and cheap too! A cloudwarmer with gain! You may want
>to increase or decrease the angle of radiation by raising or
>lowering the antenna. It all depends upon the distance from your
>QTH to a highly populated area. At a decent height this thing
>may even perform well as a DX antenna. Though it doesn't exhibit
>huge gain compared to other antennas that could be used, the
>important consideration is that you are equally loud in all
>directions and not just louder in one direction. It's OKay to be
>3 or 4 db weaker in one direction vs a yagi when you're 15 db
>louder in the other direction!
>I plan on putting up an 80 meter version to see how
>it plays vs my so-so single inverted vee at 50 feet. If I had
>the tower height I would install another 40m NUKer at a half wl
>above the present one and feed them in phase. This could
>possibly increase the gain from 3 to 6db over a dipole.
>Hopefully the Omnidirectional pattern would remain. ( how about
>a model for that Ty,K3MM??) Anyone interested in trying a set of
>these antennas spaced either 1/4wl or 1/2 wl above and below
>each other??
>The success you might have with this
>antenna will vary with your location. Someone who duplicates the
>exact antenna I have up and who lives in Eastern,PA or Chicago
>will be Loud at all times into South Carolina which probably
>won't help you much in Sweepstakes or NAQP. Play with the
>heights,combinations,etc. The results may surprise you!
>Before the antenna went up numerous hams told me it wouldn't
>work. Something about the proximity of the vees and
>cancellation,etc. Well, I am happy to report that it really does
>work!
>73 Ken N4UK
>
>P.S. I fell short of the Roanoke division record by about 20k
>points but not because of the antennas. Hey, I made a couple of
>booboos that I shouldn't have made. Looking forward to next
>year! Ken
>
>P.S. The ARRL Roanoke division record was broken the next year with 40m
again
>having the most Qs.
>
>
>I take no responsibility for typos,miscalculations,errors,poor
>assumptions etc. If you spot such an animal please E-mail me
>personally and let me know and don't embarrass me publically in
>front of the whole reflector. Tnx :)
>RE: The Great Sweepstakes Antenna
>Tyler, K3MM (KF3P) sent me some more info based on a model
>using A/O modeling software. There was some confusion as to
>where the 3db "gain" was and this sets the record straight.
>
>Compared to a dipole at 40 feet, it's about 1 db more gain
>straight up.Note that all these are measurements over
>ground...ie with ground "bounce"DB's added in.
>The broadside direction gain of the dipole is at least 2 db
>higher from 5 degrees up to 45 degrees.Off the ends of the
>dipole, the N4UK beats it at all angles, with about .7
>db advantage overhead, 3db at 45 degrees up , and 8 db at 10
>degrees.So, it's a good high angle omni antenna, but it's not as
>good as a dipole at most takeoff angles in the perfect broadside
>direction. I set them both the same at 7.1, which is what I did.
>
>73, Tyler K3MM
>I think Tyler might have meant 8db at 70 or 90 degrees and not
>10 degrees. The 3-8 db better at the 45-90 degree range is what
>works at MY QTH due to the distances from here to the Major
>Metro areas NE,NW,and NW of me. A dipole and a vertical that was
>previously used here had takeoff angles that were just too low
>for use in domestic contests. My signal was going above and
>beyond the intended Metro target areas using those antennas.
>Remember that this antenna was not intended as a DX contest
>antenna.
>Thanks to Tyler for the modeling work! 73 Ken N4UK
>
>Bill Coleman <aa4lr@arrl.net> wrote:
>I know many of you have moved on to CQWW CW, but I'm still digesting what
>happened during SS Phone. Here's some of my thoughts.
>* 40m sloper just does not cut it when the band is full of region 1 QRM.
>Thinking seriously of the 40m option for the A3S. It would buy me another
>10 feet, and allow me to rotate the dipole.
>
>Anyone have any suggestions?
>
>
>
>
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