StackMaster and StackMatch User KQ2M
Bob, has stacked 5/5/5/5 on 10 and 15 and I think 4/4/4 on 20m using two StackMasters and a StackMatch respectively.
He also has a custom 160m StackMatch for Verticals. Its basically a Standard StackMatch with a bigger transformer (more windings and using teflon wires) for heavy 160m use. His inverted Ls are not very tall but they sure play well. He feeds them in BIP/BOP to get Broadside and End fire patterns.
Here are a couple of very insightful posts to the towertalk and 3830 reflector Bob has made. The first one is an excellent summary of how changing the angles is important in a contest as the ionosphere changes during the day.
[TowerTalk] Takeoff angles - some practical experience
Tue, 19 Dec 2000 13:20:47 -0500
"Robert Shohet" <email@example.com>
This topic has already been covered extensively from the theoretical and scientific viewpoints. I am somewhat lacking in those areas but I thought it might be helpful for me to share some of my observations strictly from the standpoint of a contester who has extensively guest-operated (and from home in the past three years) with all different kinds of antenna systems from all over the Northeast in all different contests for the past 20+ years.
First, there are no absolutes. Propagation is three dimensional (vertical/horizontal radiation plus shapes of the lobes). It is also
affected by changes in the ionosphere (which is varying second by second), which in turn is affected by time of day, time of year, time of cycle, sun "stuff", etc. THEN, you have the effects of antennas which of course depend on design, height, stacking (or not), phasing (or not), feedline losses, radiation efficiency, etc. Then of course there is terrain. And finally, there is the awareness and intervention of the operator, equipment and of course, other activity on the band.
In other words, there is an INFINITE number of possible permutations which vary second by second for a given qth, operator and equipment modified further by all the above. So much for uniform observations and absolute statements! Now for the practical.....
At every location there are "magic" heights, these being the height(s) at which a good antenna, properly built and installed seem to cover most of the angles, most of the time, even when logic dictates otherwise. This magic height will vary depending on ionospheric changes and the current "place" in the sunspot cycle since the angles at which the desired signals are propagated will also change, higher antennas generally more useful at the bottom of the cycle and lower antennas more useful at the top of the cycle.
Having said that, I have found through the personal experience of operating more than 200 DX contests at all different stations and station locations, that hill-top locations seem to have LESS difference between antenna combinations than over flat ground. I have also noticed that higher antennas at hill-top locations seem to suffer less vs low antennas with high-angle condx than the differences over level ground. I will confine my observations to Europe.
Many times in the past two years, my top 10 & 15 were superior most of the weekend to all signals vs the lower antennas or combinations. This is not uniform. The higher antennas always opened and closed the band and in between, generally as the MUF rose (and I stayed on a given band) progressively lower antenna combos in-turn became superior and the opposite as the MUF dropped, though (less than 1% of the time) was the lowest antenna by itself, superior. In between, the "best" antenna combo
CONSTANTLY changed every few minutes, sometimes even every few seconds. Since I have a WX0B stackmatch and 4 identical antennas on 10 and 15, I am CONSTANTLY listening and changing the antenna combo as necessary. Often what is best at 1300z in down an s-unit or two at 1305z, 1310z etc. Cndx are ALWAYS changing. Sometimes in the middle of an opening, the highest
antenna, becomes, best, sometimes the lowest. The other thing I can be certain of, is that it is CONSTANTLY changing and the differences between antennas 2 & 3 vs 3 & 4 can be 1 - 2 s-units in a matter of 10 seconds! This is NORMAL!
If you have the "proper" stacking distances between antennas (generally 22' on 10M, 31' on 15M and 43' on 20) you will see even MORE pronounced differences, again, MODIFIED by QTH and your proximity to the desired area of signal.
During an opening, usually the further away stations are louder on the lower angle (higher) antennas. For example, at 1300Z with really good cndx it is common to see DL's peaking on the 15 meter 30' & 60' antennas and UA3's louder on the 60'/90' antennas. A VQ9 might be louder still on the 90' or 109' antennas. Likewise an EA could be several s-units down on the top antenna and might actually be loudest on the 30' by itself. Of course we are NOT talking about disturbed propagation where SOMETIMES the lowest
antenna is best or sometimes the highest antenna is the only things that "hears". We are also not talking about ionospheric ducting, sporadic E, Transequatorial (TE) skip, aurora or meteor scatter, all things that blow conventional "logic" to hell. We have been "blessed" by all the above in the past few months in CQWWSSB, CQWWCW, ARRL10, complicating matters even more, where on in the ARRL 10M contest on Saturday I made most of the EU qso;s on the 45/70' stack in the morning, most on the 22/45' stack in the
afternoon and then EVERYTHING on the 100' footer on Sunday.
Then you get top of the cycle phenomena where 20 "opens" to EU in late afternoon with the 43' antenna and works its way UP in height as darkness approaches - same with 40 meters.
A really interesting Northeast phenomena is the JA path with good cndx, where in the late afternoon on 15 in the Spring, at my qth in SW CT 15 miles from the NY border, JA peaks at about 15 degrees (NOT the usual 335!) on the 109' antenna, about 0 degrees on the 60' antenna and 340 degrees on the 30' antenna. This is not unusual either. Since phasing antennas changes the wave angles, sometimes I then have to rotate the antenna AFTER I stack different antennas!
You can also see this on 15 with EU during the 10M contest. Sometimes the high antenna (low angle) path is skewed to the North or South with the high antenna and less skewed or not at all with the low antennas. The bottom line is that there are NO absolutes. Anyone is best served by having multiple antennas at multiple heights and the ability to phase any of them at any time. It is even better if you can have OTHER types of radiators as well like a 4-sq, single vertical, delta loop, inv v etc.
Although there are some weekends where high antennas are predominantly better (usually with lower SF and a higher level of geomagnetic disturbance) and some weekends where low antennas shine it is ALWAYS best to have available combinations of antennas and keep an open mind about what "should" work best. Also keep in mind that the same antennas in the midst of the prairie DO NOT behave the same way as on the edge of a cliff, or in a valley, even if the antennas and stations are the same and only a 1/4 mile apart!
Height generally makes MORE openings possible, more often and for a longer period of time and gives you the chance to experience weird propagation paths and phenomena that are just "not there" with lower antennas.
The more operating experience one has at more and more locations, the more one realizes that no one antenna is best and the "best antenna height" will vary based on so many factors. The only thing that matters is what is likely to be best for the particular weekend you want to operate a given contest!
One final note... I have found that from my location and many others you can NOT be "too high" to South America. Often a 150' antenna hears better into ZP, LU, HK, Ce, etc. than a 40' or 100' antenna regardless of cndx. I still don't understand why this is. Maybe one of the more knowledgeable guys on this reflector can explain it to me.
73 & may you have all the "right" heights!
Sun, 01 Feb 1998 17:34:44 -0800
From: "Robert L. Shohet" <firstname.lastname@example.org>
References: 1 , 2
> Robert L. Shohet wrote:
> > Never understood why the ARRL test has so much more U.S. activity than
> > the CQ when the CQ has so much MORE DX! The drop off in rate vs. the
> > ARRL 160 was quite noticeable as was the increase in DX stations and
> > countries worked in the CQ160 - this is always a mystery!
> > Conditions seemed to be pretty good especially Saturday night but the
> > static crashes were just MIND BOGGLING! Several weeks ago I said that
> > we (in CT) have a snow storm every 160 contest. I predicted one would
> > hit on the CQ160 weekend and it sure did! It made no difference what
> > antenna or beverage I listened on Friday night, the QRN was a minimum of
> > S9 at all times with the crashes at S9+40 DB. Finally at 0445Z on
> > Saturday I packed it in even though EU sunrise was only an hour away.
> > It was simply impossible to hear anyone who was less than S9+20 unless
> > they happened to call at the very moment when the static crash
> > subsided. It was grueling and frustrating - a typical 160 contest.
> > Saturday started with Eu in real early - about 1930Z! and then they just
> > continued to get louder as did C42A and 5B4ADA. Started to hear UA2's
> > about 2030Z - a good sign, but then the static crashes came back even
> > MORE ferocious than the night before. Some of them would last for 10
> > seconds of S9+40 noise! It was awful knowing that stations were calling
> > me that I could not hear and very frustrating for me to get 1 or 2
> > letters at a time and take up to 4-5 minutes to work someone. Looking
> > at the writeups afterward I was amazed at all the countries in EU and
> > the Middle East that I simply never heard and I realized that they
> > probably called me some point and wondered why it appeared they were
> > being ignored. Sorry!
> > Finally about 0500Z the static dropped to S9+20 and I was able to run
> > Europe albeit with difficulty. I started to call CQ during the crashes
> > trying to time it so that I would end the CQ about the time the crash
> > would subside. I had mixed success with this strategy but at least it
> > was better than just agonizing about it. Was able to work and run about
> > 125 EU the second night, by far the best ever from here. It would seem
> > that even though the apex of the Inv. L's was quite low (about 60 feet)
> > phasing them 270' apart gave me a significant improvement over last year
> > when I used only one. I wondered just how many countries and dx
> > stations I could have worked with a more reasonable noise level?
> > Was really surprised and excited when NL7Z answered my CQ at about
> > 0900Z.
> > Alaska is tough from here although I was also able to work one in the
> > ARRL160 (thanks to the phased Inv L's). Can't figure out where ND, MS
> > and DC were though! Wonderful activity from Candian Maritime provinces,
> > and VE4, 5 and 6. Worked EIGHT VE6's WOW!
> > Heard a loud CE but couldn't crack the midwest pileup working it with
> > impunity. Also heard a LOUD VK6VZ running JA's at 1145Z (he stopped
> > listening for US in favor of running JA's) and a loud JA running US.
> > Could NOT understand why the JA was listening for and working W3
> > stations ONLY for more than 30 minutes?! I listened with amazement as
> > the JA was peaking S7 on the Phased NW/SE position about 1130Z and then
> > started to peak in the NE/SW position about 1200Z. I could hear the
> > gradual shift in the path from NW to SW between 1130Z to 1200Z!
> > Never heard the ZL's, VK's, ZK, EM1, etc. that were reported by the
> > others. Wonder if I just did not have the propagation or the
> > directivity of the phased INV L's caused me not to hear them?
> > It turned out to be a much more interesting contest than I expected and
> > it was nice to "play at it" (for 20 hours) instead of pounding away hour
> > after hour with a serious effort. Even more enjoyable was the feeling
> > of being loud as witnessed by the fact that the EU stations did NOT CQ
> > on my frequency but rather stayed a few hundred HZ to either side of
> > me. This has NEVER happened before in a 160 contest. Since I never
> > used properly phased antennas before on 160, I have to believe that the
> > modified WX0B stackmatch box made the difference. Thanks Jay!
> > Congrats to W4ZV on a mind-boggling score from NC! I don't know how
> > much better EU is from CT vs NC but there clearly is no comparison
> > between working stateside from NC vs CT!
> > Thanks to all who worked me and those (especially DX stations) who
> > repeatedly tried (in vain). Maybe one day we will have a 160 contest
> > with good propagation and NORMAL winter noise levels (NO Snowstorm)?
> > I am still waiting for this rare combination to occur!
> > 73
> > Bob KQ2M
> CQ 160 METER CONTEST -- 1998