This may be of interest to other little pistols who
need to put more FUN into those contest weekends when
things are less than terrific. Last weekend looked perfect
for Multi-Contesting, working several contests at the same time.
It looked like one might be able to work the entire band
- CW (KCJ Contest), Digital (SARTG RTTY), and Phone (NA
QSO) - and even a few more (NJ QSO & SEANET Phone) .
I loaded several contest programs while Multi-tasking
them, and switching between programs to S & P thru
the bands. This was easier than one would have suspected,
and next time I wonUt have to spend so much time working
out the hardware bugs. This was a real blast, in spite
of the meager scores. Not a serious threat, maybe next time?
73 de N2ALE/6, alan
aka ames@force.decnet.lockheed.com
SARTG Worldwide RTTY
Entry Class: Single Op, All Band
Band QSOs Pts Dist DX
80 0 0 0 0
40 6 60 4 2
20 9 95 6 3
15 0 0 0 0
10 0 0 0 0
----- ---- ---- ---- ----
Total 15 155 10 5
Score: 2325
Power Output: 50
NCJ NORTH AMERICAN QSO PARTY
Category: Single Op All Band
Mode: SSB Power: 100W
Hours of Operation: 02:53
band QSOs points mults
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
160 0 0 0
75 2 2 1
40 4 4 4
20 25 25 16
15 0 0 0
10 0 0 0
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
TOTAL 31 31 21 SCORE: 651
>From Steve Fraasch <sfraasch@ATK.COM> Wed Aug 24 20:24:00 1994
From: Steve Fraasch <sfraasch@ATK.COM> (Steve Fraasch)
Subject: No subject
Message-ID: <2E5B9E89@msm.ATK.COM>
In response to comments on elevated systems: 4 radials IS NOT THE HOT TIP
!!!!!!!!!!
I've done analysis (using NEC with full Norton/Green's function expansion of
ground) of a single elevated quarter wave vertical mounted 10' off ground
(.04 wave ht @ 75m) with 4, 8, 12, and 16 radials. Test freq was 3.8 Mhz.
16 radials provide additional gain, and a lower takeoff than 4 radials.
The 4 radial configuration sufffered from poor efficiency (high real part
of drive impedance), whereas the real part of the drive impedance converged
for 16 radials, and high efficiency was obtained. 12 provided similar
results, with 1 or 2 Ohms Re[Z] change going from 12 to 16. Because of
limited computer memory, I could not analyze greater than 16 radials. Also,
the best length was ~ 100' (3/8 wave) which provided slightly better
performance than quarter wave radials. Half-wave radials provided poor
performance: I suspect due to the half-wave transmission line effect which
transfers the far side open to the tower connection thus impeding, rather
than conducting currents (The elevated radial will begin to act more like a
transmission line when it's a few feet off the ground).
Mark, K0KX, has verified same in practice on his 4 square. 4 radials had a
definite "limp" feeling, whereas 16 provided much more "noise" in the
receiver, and much improved signal reports on xmit. He is using 100'
radials which seem to work the best.
I will publish the NEC results on the reflector when I bring the results
from home.
Point: Forget about 4 elevated radials: use 12 - 16. I cannot verify Al
Christman's results, but someone else is welcome to try. The most salient
point I can give against 4 elevated radials is this configuration cannot
work well if the real part of the drive impedance changes so drastically
going from 4 to 12, yet change slightly from 12 to 16 radials. I would not
want an antenna, and certainly not an array element that is that sensitive
to ground plane characteristics. Moreover, Mark's and my observation of his
4 radial elevated vertical was that the antenna was "dead."
Steve Fraasch, K0SF
sfraasch@atk.com
>From Skelton, Tom" <TSkelton@engineer.clemsonsc.NCR.COM Wed Aug 24 19:27:00
>1994
From: Skelton, Tom" <TSkelton@engineer.clemsonsc.NCR.COM (Skelton, Tom)
Subject: more on elevated radials
Message-ID: <2E5B9318@admin.ClemsonSC.NCR.COM>
----------
From: owner-cq-contest
To: cq-contest
Subject: ADDENDUM to my input to KM9P's posting on elevated radials
<John's good technical stuff deleted>
Just wanted to clarify one point about radials now that m. Raising them
just a few
inches from the ground greatly reduces the detuning effect of the ground,
but they need to be significantly (5-10 ft on 80 and 10-20 ft on 160)
off the ground to become efficient elevated radials.
Hope this is a tidbit of useful information to be added to my comments.
73 John W0UN broz@csn.org
----------
Here's a real-world lesson I luckily stumbled into. I have been fortunate
enough to operate from Bermuda on 2 occasions out of 3 trips there, and
both of them used the same antenna, same power level (100 watts for
visitors), and same exact QTH. (My other Bermuda trip was a honeymoon
in 1989, and the only DX I worked then was 20 cm...go figger and email me
with your jokes. Wife said no radio on honeymoon.)
The first trip I had the Butternut HF6V vertical ground mounted
with what-I-thought-were-and-should-be-resonant ground-mounted
radials (I've since gained some great knowledge from all you gurus on the
net): 2 on 80, 4 on 40, 8 on 20, 4 on 15 and 4 on 10. This trip was
summer
of 1987 for the IARU test...I struggled miserably and managed to work about
500 QSO's. I was definitely disappointed with my signal level, inability to
get a run freq, inability to hold off the Europeans who were successfully
running, etc. My first out-of-the-country contest experience was a
failure in my mind.
The second trip I took the same antenna but got it mounted on the roof
of the house --- about 20 feet off the ground. My contingent of radials
was the basically the same, but they were tied off to various trees and
shrubs
around the yard. I was about to learn the lesson of elevated radials and
didn't even know it. During the 1992 ARRL phone test, even with 100
watts, I had runs on the bands that pleasantly surprised me. I had lots
of comments on 80 and 40 about what a good signal I had, and I
attribute it all to the elevated radials. Yeah, the QRN is lower in spring
than in summer but I also did real well on 10 and 15 meters....I had to
stay off 15 most of the time due to severe telephone RFI, however,
and probably missed 200-300 QSO's. My final QSO total was
1,904..... far better than the 1987 trip.
Elevated radials: great for low band antennas!
73 Tom WB4iUX
(Tom.Skelton@ClemsonSC.NCR.COM)
>From Steve Fraasch <sfraasch@ATK.COM> Wed Aug 24 20:45:00 1994
From: Steve Fraasch <sfraasch@ATK.COM> (Steve Fraasch)
Subject: 4 Elevated Radials
Message-ID: <2E5BA37C@msm.ATK.COM>
In response to comments on elevated systems: 4 radials IS NOT THE HOT TIP
!!!!!!!!!!
I've done analysis (using NEC with full Norton/Green's function expansion of
ground) of a single elevated quarter wave vertical mounted 10' off ground
(.04 wave ht @ 75m) with 4, 8, 12, and 16 radials. Test freq was 3.8 Mhz.
16 radials provide additional gain, and a lower takeoff than 4 radials.
The 4 radial configuration sufffered from poor efficiency (high real part
of drive impedance), whereas the real part of the drive impedance converged
for 16 radials, and high efficiency was obtained. 12 provided similar
results, with 1 or 2 Ohms Re[Z] change going from 12 to 16. Because of
limited computer memory, I could not analyze greater than 16 radials. Also,
the best length was ~ 100' (3/8 wave) which provided slightly better
performance than quarter wave radials. Half-wave radials provided poor
performance: I suspect due to the half-wave transmission line effect which
transfers the far side open to the tower connection thus impeding, rather
than conducting currents (The elevated radial will begin to act more like a
transmission line when it's a few feet off the ground).
Mark, K0KX, has verified same in practice on his 4 square. 4 radials had a
definite "limp" feeling, whereas 16 provided much more "noise" in the
receiver, and much improved signal reports on xmit. He is using 100'
radials which seem to work the best.
I will publish the NEC results on the reflector when I bring the results
from home.
Point: Forget about 4 elevated radials: use 12 - 16. I cannot verify Al
Christman's results, but someone else is welcome to try. The most salient
point I can give against 4 elevated radials is this configuration cannot
work well if the real part of the drive impedance changes so drastically
going from 4 to 12, yet change slightly from 12 to 16 radials. I would not
want an antenna, and certainly not an array element that is that sensitive
to ground plane characteristics. Moreover, Mark's and my observation of his
4 radial elevated vertical was that the antenna was "dead."
Steve Fraasch, K0SF
sfraasch@atk.com
|