Conversation, na8v and w4an on high 10 meter beams:
NA8V said:
Bill:
My 2 cents worth sent to Rick a few days ago. Note that the drop off
I speak of was about 100' in 1/4 mile, 50' in a couple hundred yards.
All the antennas saw it into JA, the 48' ant was "high" into JA.
Also, the 170' antenna was never better into zl/vk for the same
reason.
On every antenna I've had, the higher the quieter - everything else
being equal. Only 2 exceptions were on the higher bands when they
were REALLY open - 1) heard lots of "wierd noises" on the high
antennas that I assume were spurs/birdies/other types of signals from
far away, (especially on 10 from the w and nw) and 2) sun noise when
beaming right down the greyline shortly after band opening (say at
about 13z on 15).
Still think for a REAL high antenna to be effective (for contesting),
especially when compared to a stack, it must be a long boom job.
Sounds like you've got a good selection to go with.
Greg na8v/4
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__________________________________ Subject: too high antenna?
To: <towertalk@contesting.com>
Author: Henry G Chapoton at gdlsTallahassee Date: 10/8/97 9:29 AM
Rick:
A few years back I tried a W2PV on 10 (4 el, 20' boom) up at 175'.
Main antennas were a 7 el/42'boom @ 90' and a 6 el/36' boom at 48'.
This was as the spots were just beginning to decline. Thought was
that it would be a good multiplier antenna, and extend the eu and ja
openings. Found that it was a fair antenna - boom was just too short.
Was usually that "1-2 s units" down-my s units are 3db. It was
better into eu at the end of the opening for about 15 min.- not really
worthwhile for contesting - it was time for a bandchange anyway. It
would work the off direction multipliers, but if there was a pile I
needed one of the longer booms. This antenna also suffered from
excess feedline loss (1-1.5 db) compared to the others. I was on the
side of hill with a good drop off to the west and nw, so saw NO
advantage to ja/pacific.
I think your's will work ok, but its hard to beat a good long boom
antenna. Do you have a GOOD feedline on it? Wait until there are
some real openings. I bet it will beat the low ones on the ja
openings and also on the "deep" Russia/central asia path. The high
one may not always be loudest, but it may be more consistent. I used
my 48' high during the spot peak for eu, but only after the z17/21
stuff was gone - they only came back to the 90'. I also always used
the 90' ant to africa - receive often wasn't as loud, but xmit was
always better. Think that was a product of the multiple lobes.
Bottom line: more antenna are better antennas, and very high antennas
are great antennas - BUT they need to have a reasonable chance
(gain/feedline) from the get go. Also, from experience, you need to
know which one to use when/where. Note that my comments are based on
operating in MI, which is a whole different ballgame than the South.
Low angle was much more important up there.
Have fun,
Greg na8v/4
Subject: Re: too high antenna?
Author: Bill Fisher - W4AN <w4an@contesting.com> at Internet/Unix
To: <towertalk@contesting.com>
Date: 10/13/97 3:59 PM
> Still think for a REAL high antenna to be effective (for
contesting),
> especially when compared to a stack, it must be a long boom
job.
I have to disagree with this one. I have seen very drastic
differences between antennas at different heights. I have never seen
drastic differences between antennas with different boom lengths at
the same height. This makes sense if you think about it. Whats the
difference between a 4el and 6el yagi? 1DB? Maybe 1.5DB? You wont
get a G3 to tell you he can hear that very often I bet. But you take
a 3 el 20M yagi and stick it up at 210' with low loss feedline and I
bet you find times where that antenna is MUCH better than anything
else regardless of boom length.
NA8V replied:
Well, guess I have to disagree w/ you. Talking 10 m., I was comparing
170' with 90'. 90' is already relatively high in terms of wl.,
therefore one won't see the difference from a REAL high antenna as
often, which most often is at the lowest angles. Also, I was speaking
in reference to 1) a stack - where if you have big beams you get 5db
over a small, single beam and 2) frequently the "off" or multiplier
antenna needs to break a pile-up.
I agree with you about 20 meters, having used Duffy's stuff, and
having had antennas at all different heights. Remember that in your
example of 210' on 20 it's only 105' on 10 - I think that that may be
a point where diminishing returns begin to come into play - Anecdotal
evidence aside (K6EBB worked a G on 10 w/3el at 180', nobody out here
worked one) - in single op contesting particularly rate is a key
factor, and the REAL high antenna won't give you that very often
(still talking 10 here - REAL high must be defined in terms of wl, NOT
in terms of common hardware - 200' is not real high on 40)
I remember 2 specific instances on 20: listening to a UA9, stack of
5el/46'boom at 65/125 and a 205ba @80'- bottom beam, barely readable,
205 - s5-7, top beam - s9, and stack well over 9. The other was a WPX
with a single 205ba at 160' - at 10z sunday morning, I could hear all
the west eu talking to each other, not working any US. It was like I
was on their continent.
Bottom line: very low angle is often far superior, BUT is there a
point where the lower angle doesn't propagate any better?
On 10, where high (w/l) antennas are easy (100-120'), one needs to get
as much gain as possible to differentiate from the crowd. That would
be as big (boom) a stack as practical- and 3 or 4 high would be a way
to go. Note how dominating w9re has been on 15 the last few years
since he went to his 4 high, both gain AND low angle.
As far as gain goes, I would expect my 42' yagi (a dl1bu) to have
2.5-3db gain over the 20'(w2pv) one. That is the same as a doubling
of power. While the g3 may not notice a big difference, the t77 will
pick you out of a pile a HECK of a lot quicker.
btw, you'll love a full size 3 el 40. Might want to keep it on the
low side? 100-120'? Mine was frequently too high in the mid-opening,
although a killer at 0800z and before sunset (2nd lobe?). it was at
170'.
Greg
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