ARRL JUNE VHF QSO PARTY 1995 RESULTS
W9SZ QRP portable from EN60af, Rural Compromise Township, Champaign
County IL
Band QSOs Points Grids
144 32 32 17
432 16 32 12
TOTAL 48 64 29 = 1,856 Points
Equipment: HTX-100 IF rig
Homebrew transverters for 144, 432, 1296 MHz, 5 watts out
12-el Yagi on 144, 15-el Yagi on 432, 24-el loop yagi in 1296
Comments: Murphy struck early when I got to the hilltop and found out I
forgot a critical component (26-dB attenuator) for the 1296-MHz transmit
chain. So I could hear fine on that band but couldn't transmit! Oh well,
try again next time!
The weather decided to produce rain on Sunday morning (I only
operated on Sunday) but the front coming through didn't produce any band
openings. The front came through and dropped the temperature AND the
band conditions. (At least no mosquitoes!) It got CHILLY Sunday evening!
I had fun even though no spectacular conditions and got a few new grids.
See you all next time. Thanks for the QSOs!
73, Zack W9SZ
>From engberg@ctis.af.mil (Bob Engberg) Mon Jun 12 11:08:17 1995
From: engberg@ctis.af.mil (Bob Engberg) (Bob Engberg)
Subject: Summary: Tower Cement
Message-ID: <9506121808.AA05964@edfue0.ctis.af.mil>
Several people asked me to post the summary. Here it is:
Listed below are the responses to my question on tower cement.
Thanks everyone for the good advise and references.
____ ____ ____ ____ ____ ____ ____ ____
Here's the question:
I have a 3x3x5 ft hole for my Rohn 25G tower.
Locally a pea-gravel mix is available. Just add water. Is this
the "right stuff"? I sorta recall using a sand mixture last time -
about 15 yrs ago.
[I forgot to mention in the original question that the tower will be 60-70 ft.
with my old TH6DXX.]
_____ ____ ____ ____ ____ ____ ____ ____
Here are the answers I received:
I suggest that you use a batch -plant prepared mix. It is a stronger mix
than you can buy in a bag and mix with water. I would assume from the tower
you are installing that you will be using guy wires. To me it makes little
difference. Use quality products and prevent things liked a cracked base.
I would suggest a 6 sack, pea gravel mix which will
test to 6,000 psi at 28 days of curing and it can be pumped into place for a
modest price.
Pumping the base makes the next to last phase a real piece of cake.
Good luck with your project. I will work you in the contest under my call
of 6E2T.
73,
Harv
KD6QK
hhiller@cts.com
____ ____ ____ ____ ____ ____ ____ _____
The Book (Rohn) says to guy at 35 and 70 using 500 ft of 3/16
with the anchors 55 feet from the base. The base should be
2 by 2 by 4. [they have different size bases and guying depending
on wind load. This is for 80mph. Conservative numbers.]
But here is what I do:
I guy just below the top section. [That allows me to add to the tower
in the future. All I have to do is pop off the top section and add
tower sections.]
I dig the hole making it square. I don't go down 4 feet. Three
feet is okay for Fairbanks. I went 5 feet for the 190 foot and
4 foot for 150 ft. The 125 foot towers are 3 feet. [The hole is
made square by using a hoe on the sides. I even get into
the hole and polish the sides to make it square as possible. The
idea is you don't want it (the concrete block) to rock back and
forth in the wind. ie round hold is bad.]
I build a concrete form out of 2 by 4 boards and place it over the
hole. I hand pack around the outside of the form with dirt. This will
give you a square block that is 3 1/2 inches about ground. You trowel
this off away from the tower for water run off. [no standing water]
I add sand to the hole about 5 inches. When I put the tower into the
hole it is pushed into the sand. [This is to allow water to escape the
tower legs if any gets in to it. [no standing water]. [the tower
section acts like rebar- no other added]
I place the tower section into the hole. Usually two sections. Guy
the top off with rope to near by stakes. I use a level and make the
section straight up/down. [this is very hard to do after you get much
concret into the hole. Also make sure the tower angle is correct to
the guy points. Trying to turn a tower when its in only a small amount
of mud is very very hard.] An easy way to keep the tower straight
is to get a long board and just spike it to the ground and have it
resting against the tower. This keeps pressure on the tower to keep
it straight. It doesn't take long to "set" the position.
I rent a mixer. Add 5 shovels pea gravel#2 and one shovel cement and water
to mixer. Let it mix for few seconds then pour into hole. Notice that the
first pour didn't do much. Just a wad of grey mud at the bottom.
I fill the hole completely with cement. I do not fill mostly with sand
then top off or do I throw rocks, beer cans etc into the hole. I thought
about throwing my daughter in one time when she ran off with the hose
to squirt her brother.
Thats it. I had a dumptruck load of #2 dumped in the woods near my house
and have been feeding off that for last 10 years. The concret is about $8
bucks a bag and need only 2 or 3. I throw away the unused stuff because
frezzing ruins it and I dont trust it any more. To rent a mixer is
$45 a day, but I get the big one.
Rich kl7ra@icefog.gcgo.nasa.gov
____ ____ ____ ____ ____ ____ ____ _____
Bob, I am NOT the expert on this but I've done 3 25G tower
holes and here's what I understand: (I an EE, not Civil E)
The cement does only 1 thing, and that is provide the weight
to keep the first 30 feet vertical. After that, the guy wires
equalize the forces and keep the tower vertical. So, you don't
need any special cement or rebar in your hole. Just make sure
you have plenty of cement, not too much aggregate (sp?...
you know, rocks/gravel/etc) and let it get good and hard
(48 hours curing) before you start adding the other sections.
Works for me, and is what I'll do on the new tower when I
move next month.
73, Tom WB4iUX
Tom.Skelton@ClemsonSC.ATTGIS.COM
____ ____ ____ ____ ____ ____ ____ _____
You didn't say what you were going to put on the tower, nor did you say how
high it would be, but my advice is to use the "standard" strength concrete
that is meant for steel towers and that is 3000 psi. That mix would be a
minimum of 5-1/2 sacks of cement mixed with less than 6-1/2 gallons of
water/sack and coarse aggregate (max size 3/4 inch)[I used exactly 3/4 in
stone] and average size sand.
Reference: page 10-23,24 of: Physical Design of Yagi Antennas by David B.
Leeson, W6QHS, Published by ARRL, 1992.
73...
Bill, n3rr@cais.com
_____ ____ ____ ____ ____ ____ ____ ____
The premix is really expensive to use. One bag only does 1 cubic foot.
Best to get pea gravel #2 and mix it 5 to one.
I have seven towers 190 feet on down up for years in Fairbanks. So far
the base of each tower looks good. No cracking etc.
73 Rich kl7ra@icefog.gcgo.nasa.gov
___ ____ ____ ____ ____ ____ ____ _____
1. I am not a civil engineer.
that being said...
2. Concrete is usually specified in terms of P.S.I. and stone size.
3000 psi is the common garden variety stuff, and should be good enough
for tower work. If you want to be on the safe side, you can go to
higher numbers. I think I used 4000 psi (or better) for my rohn 45.
-Tony, K1KP, fisher@hp-and.an.hp.com
____ ____ ____ ____ ____ ____ ____ ____
I believe the sand and cement mixture you speak of is mortar, used to bond
brick and blocks. Concrete, or ready-mixed is a mixture of sand, gravel and
cement. That is what you want for your tower base. And what it takes to
fill that 3X3X5 hole is a lot of hand mixing, for that matter, it's a lot of
mixing with a machine. If you have a ready-mix company near by, they might
be able to deliver to you on an over flow basis when they have a nearby
delivery.
Good Luck,
73, K8Joe"Palooka"
jpontek@aol.com
____ ____ ____ ____ ____ ____ ____ _____
For whatever it's worth, here's what the Rohn drawings have to say about
the concrete to be used -- you may be able to find some of the cited
specs, etc. on the bag. Alternatively, Dave Leeson has some words on the
right concrete to use in his book on physical yagi design - unfortunately
it's at home.
>From Rohn:
"7. Concrete materials shall conform to the appropriate state
requirements for exposed structural concrete."
...
8. Proportions of concrete materials shall be suitablefor the
installation method utilized and shall result in durable concrete for
resistance to local anticipated aggressive actions (sic). The durability
requirements of ACI 318 shall be satisfied based on the conditions
expected at the site. As a minimum, concrete shall develop a minimum
compressive strength of 3000 PSI in 28 days."
9. Maximum size of aggregate shall not exceed 3/4 inch; size suitable
for installation utilized; or one-third clear distance behind or between
reinforcing.
...
13. Minimum concrete cover for reinforcement shall be 3 inches unless
otherwise noted."
This would seem to indicate that your pea-gravel stuff would be OK. Good
luck
73, Pete
N4ZR@netcom.com
>From Chad Kurszewski" <kurscj@OAMPC12.csg.mot.com Mon Jun 12 20:01:48 1995
From: Chad Kurszewski" <kurscj@OAMPC12.csg.mot.com (Chad Kurszewski)
Subject: CW and VHF contests
References: <199506121747.AA24358@mephisto.physics.uiuc.edu>
Message-ID: <9506121401.ZM9263@WE9V>
> Why do VHF operators have such an aversion to CW? In my limited experience
> in VHF contesting, (this year & last year in June contests), some of the
> big gun stations could make a lot more qso's if they would try CW a little.
> Both this year and last on 2m, I listened to many guys endlessly calling cq
> on ssb while myself (and other small stations) tried calling them. Often,
> I think using CW would be the difference in making the qso...especially
> when the band is dead, with only weak tropo condx. Occaisionally I managed
a
> cross-mode qso.
> This was the second year that AA9D couldn't hear me...
> (Who operated some from W9YH (EN50) on 2m, 10w + 10el yagi at 25 ft)
GA, Tor.
If I recall, I worked you, from a much further north grid, from K9JK/R.
I think we were in EN54 or 64 at the time. Can't remember if it was a
cross-mode Q or not.
This was my first VHF/UHF contest, and being mostly a HF contestor, I
had no problems copying the fast code. In fact, several times I called
CQ in CW, particularily on 432. In most cases though, I had far more
cross mode Qs when the other guy was using CW. We ain't no big station,
just a 'lowly' rover, but we must have gotten out pretty well.
Even though AA9D was our 'mother' station, it seems that several of the
ops are a little slow (and I'm not talking about their code speed either).
For example, they KNEW that we would be north of them on Sunday. Whenever
we would try to call them, they would say, "The kilo 9 japan something
rover station, try it again." This would go on indefinitely. Come on!
We were supposed to be 'their' rover....they could at least remember the
call. I mean we only worked them countless times on Saturday. So anyway,
they just couldn't pull us out. Then finally, their signal would jump up
like 30dB or so and say, "Oh, K9JK/R, EN52". Those idiots should have
figured that we would be much louder when they aim their antennas north.
Duh. (Can you figure out by my affection for AA9D that I'm not one of
their groupies? I was just along for the ride. I was so disgusted with
their abilities that at the end of the contest, I didn't even bother with
passing them anymore.)
Oh well. In general, it was fun. We 'toured' 12 grids, starting in
EM59/69 and travelling north to EN54/64. K9JK/R made the most QSOs
ever, just over 500. When I asked John, K9JK, why does he think that
we made so many Qs, he responded, "Good conditions". IMHO, it was
because his partner being a competent contester, who isn't afraid of
the code either!
Sorry to talk off your ear!
73
--
Chad Kurszewski, WE9V e-mail: Chad_Kurszewski@csg.mot.com
Sultans of Shwing Loud is Cool....yeah, heh, heh, heh, LOUD IS COOL!!!
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