Tower Help
K7LXC at aol.com
K7LXC at aol.com
Thu Feb 8 15:02:03 EST 1996
In a message dated 96-02-08 13:45:52 EST, you write:
> How do you determine the sq. ft. wind load of an
>antenna? I have a Cushcraft A3, and I'm thinking of adding a 40m kit to it
>when it goes up (probably this summer). I can't find anything in the
>specifications that defines the wind load.
>
>Is there some simple calculation for this? This this the aerodynamic flat
>plate equivalent?
>
>Thanks.
>
>Bill Coleman, AA4LR
Hiya, Bill --
There's a long answer and a short answer. The long answer is to get Dr.
Dave Leeson's (W6QHS) book on yagi design and crank through cylindrical
multisection modulus, moment and other various calculations. The short
answer is to get the manufacturer's catalog -- it'll be listed in the specs.
If you want one publication that has all of the antennas, rotators plus
various other products complete specs, pick up a copy of the CQ Antenna
Buyer's Guide; it's a good reference for lots of specs. Contact your local
dealer or call CQ direct for the latest copy.
Regarding the Cushcraft 40M add-on kit, it's got negative gain compared to
a dipole; put up the dipole instead if possible.
73, Steve K7LXC
"Up The Tower" now appears in CQ Contest magazine
>From Pete Smith <n4zr at ix.netcom.com> Thu Feb 8 20:04:16 1996
From: Pete Smith <n4zr at ix.netcom.com> (Pete Smith)
Date: Thu, 8 Feb 1996 12:04:16 -0800
Subject: Tribander stack/spacing
Message-ID: <199602082004.MAA26932 at ix3.ix.netcom.com>
For the header-impaired, my apologies. I reloaded Eudora last week, and
just realized that I forgot to reload the signature file (yup, a hard drive
went). So I've been blithely sending or replying to messages, thinking that
each of my outgoings had a signature.
Sorry....
73,
Pete Smith N4ZR (n4zr at ix.netcom.com)
>From lvn at fox.cen.com (Larry Novak) Thu Feb 8 21:42:40 1996
From: lvn at fox.cen.com (Larry Novak) (Larry Novak)
Date: Thu, 8 Feb 96 16:42:40 EST
Subject: Contest Registry: Update
Message-ID: <9602082142.AA02003 at cen.com>
CQ Contest DXpedition Registery.
Updated February 8, 1996
This is a listing of planned contest Dxpeditions. If you have additions
or corrections, please email to lnovak at cen.com or via packet to K3TLX.
73, Larry, K3TLX
Contest Location Who/email Status
------------------------------------------------------------------
NCJ/CW Sprint VP2E/KI4HN KI4HN Low power, 20M only.
ki4hn at nando.net
------------------------------------------------------------------
ARRL DX CW FS WX9E Firm SOLP
ARRL DX CW J2 Bruce, AA6KX Probable SOAB
** CANCELLED ** AA6KX at aol.com
ARRL DX CW KG4NA KD4D Planned SOAB
bailey at integ.com
ARRL DX CW TU5A G3SXW, etal Multi-2
Via W8AEF 100260.342 at compuserve.com
ARRL DX CW V31EV NS0B, WC0W & WG9L
albraun at socketis.net
ARRL DX CW V31JZ NN7A, NG7S M/S
ARRL DX CW V4 N0BSH SOAB
N0bsh at aol.com
ARRL DX CW VP2E KI4HN and AA4NC Firm M/S
ki4hn at nando.net
ARRL DX CW VP5 K8JP SO
palooka at pyrotechnics.com
ARRL DX CW XE2EBE AA6DP, NF6H, et al M/S Confirmed
dab at kaiwan.com
ARRL DX CW ZF2OP K3DI SO/QRP
wilder at clark.new
ARRL DX CW ZF Joe, W5ASP
Jastaples at aol.com
------------------------------------------------------------------
ARRL DX SSB 8P K3KG, K3ZR & K4FJ M/S firm
K4FJ at aol.com
ARRL DX SSB FM WJ2O Planned SOHP
(NOTE CHANGE FROM FP) WJ2O at aol.com
ARRL DX SSB FS N0BSH, WE9V, WX9E etal Firm Multi-2
n0bsh at aol.com
ARRL DX SSB J37K W8KKF SO
hflasher at dayton.net
ARRL DX SSB J8 Society of Midwest Contesters Planned Multi-2
**CANCELLED** blckhole at ripco.com
ARRL DX SSB KH6 W2HPF SOLP
102042.621 at compuserve.com
ARRL DX SSB KP2(WP2AHW) KE2VB & WD5N Confirmed Multi-single
readerl at goliath.sunyocc.edu
ARRL DX SSB TD9IGI KA9FOX Firm SOAB
neader at centuryinter.net
ARRL DX SSB V2 Robert, WB5CRG
ARRL DX SSB V31DX N6YRU, KI6IM, WA9L Firm.
jdowning at intelenet.net
ARRL DX SSB VP2E WA0PUJ, AH9B, KC0ZC Firm M/S QSL via KC0ZC
grjohnson at vax1.bemidji.msus.edu
ARRL DX SSB VP2E YT6A PROBABLY SO LP.
w5robert at blkbox.COM
ARRL DX SSB XE2EBE AA6DP, NF6H, et al M/S Confirmed
dab at kaiwan.com
------------------------------------------------------------------
WPX SSB/96 KP4 KP4XS etal M/M
ramirezk at emi.com
WPX SSB/96 PY0F(ZX0F) PY0FF, N5FA, PY5EG, PY5CC Mutli/Single
Via PY5EG. py5cc at sul.com.br
------------------------------------------------------------------
WPX CW/96 VP5 W5ASP
Jastaples at aol.com
------------------------------------------------------------------
WAE CW/96 VP2MGA Bill, K5GA One of us, probable
VP2MGP Bob, N5RP One of us, probable
perring at ICSI.Net
------------------------------------------------------------------
IOTA/1996 GW(EU124) G5LP, G3VMW and G4BWP Firm M-S from EU-124
group at ptpropn.demon.co.uk
------------------------------------------------------------------
CQWW SSB J3A W8KKF, WA8LOW etal M/S or M/M
Additional ops considered (hflasher at dayton.net)
CQWW SSB V26B (QSL WT3Q) Confirmed Multi/Multi
N3ADL at aol.com
------------------------------------------------------------------
ARRL SS SSB KH6 WJ2O SO, speculative
WJ2O at aol.com
------------------------------------------------------------------
CQWW CW T3 WJ2O SO, speculative
WJ2O at aol.com
CQWW CW VP5 Dave, WD5N Reserved
wd5n at msg.ti.com
CQWW CW ZF2RF K4UVT, K9LA, N8SR + multi-single
k4uvt at aol.com
------------------------------------------------------------------
ARRL DX SSB/97 VP5 Glenn, WA0PUJ Reserved
--
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+
| Larry Novak \-\-\ email: lnovak at cen.com |
| Century Computing, Inc. | Tel: (301) 953-3330 |
| 8101 Sandy Spring Road | Tel (@NRL): (202) 404-7682 |
| Suite 200 | Fax: (301) 953-2368 |
| Laurel, MD 20707 | Amateur Radio: K3TLX, C6AHE |
| http://www.cen.com/ | |
+=-=-=-=-=-=-=-=-=---=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+
+ INSULATOR COLLECTOR'S: http://www.resilience.com/insulators/ +
+=-=-=-=-=-=-=-=-=---=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+
>From David Robbins <robbins at berkshire.net> Fri Feb 9 06:36:21 1996
From: David Robbins <robbins at berkshire.net> (David Robbins)
Date: Thu, 08 Feb 1996 22:36:21 -0800
Subject: ts-870 interesting failure
References: <199602081832.NAA26160 at sable.cc.vt.edu>
Message-ID: <311AEB65.6735 at berkshire.net>
JOHN MITCHELL wrote:
>
> The investigation
> >also showed that the "RX ant" jack on the back has a similar bulb plus
> >resistor in series with it.... plugging the beverage cable into the rx
> >ant jack restored the 870's RX for the rest of the contest.
>
> Hi David
>
> What I find REALLY interesting is that that "RX Ant jack worked as a
> beverage input!!! According to the manual, all this jack does is split the
> antenna signal going OUT of the 870 so that an external recvr can be used.
> There is a menu item to activate this feature. Did plugging the beverage
> into this jack only work because the main rcvr input was blown? Or do you
> find that the so called RX out jack works as an external RX ant input,
> perhaps when not "activated" on the menu??? Please let me know, as I now
> have to switch my beverages manually between the two SO-239 transceive jacks
> (I haven't taken time to build an external relay arrangement)
>
> Thanx, 73, John, WD4MUR
yes, it works even without changing the menu selection. i am very
confused why it is wired in the way it is. the problem would be that
it would be in parallel with the antenna on the so-239 if you just put
the beverage in that jack, with no way to cut it off. now, it would
be fairly easy to wire switches in place of those two bulbs to select
which antenna input went to the rx. in fact a slight rewireing of
the k1 relay that is used to activate the power splitint network
would probably make that menu item select either one or the other.
--
ky1h at berkshire.net or robbins at berkshire.net
http://www.berkshire.net/~robbins/ky1h.html
WWW Page now has New England Flea Market list from W1GSL
>From Fred Hopengarten" <k1vr at k1vr.jjm.com Thu Feb 8 19:17:22 1996
From: Fred Hopengarten" <k1vr at k1vr.jjm.com (Fred Hopengarten)
Date: Thu, 08 Feb 1996 14:17:22 EST
Subject: Tower Help
Message-ID: <311a4c46.k1vr at k1vr.jjm.com>
On Thu, 8 Feb 1996 08:50:13 -0800, "Stan Griffiths" <w7ni at teleport.com> wrote:
> I can certainly sympathize with your desire to know how to correctly design
> your tower installation so it won't fail. We had quite a thorough
> discussion here a couple of months ago where it was pretty much concluded
> that all of the engineering design expertise needed to do this job right
> could be put into a software program that could be used by the average ham
> much the same way as antenna design software is used today. The problem is
> that anyone who writes such a program is assuming a massive amount of
> liability in the event that one of the tower systems designed using the
> program fails.
Funny, I remember that thread, but I remember the conclusion
a bit differently. As I recall it, the engineers and the
faint-hearted felt that writing a software program would
subject them to liability if the system failed. At least
one lawyer (me) felt that a "waiver of liability" paragraph
embedded in the program would protect the software writer.
Perform the following thought experiment about "outcome
liability" with respect to software. Assume you are Lotus,
and you have written 1-2-3. A dunce in New York City
working for Gimbels uses 1-2-3 to create a spreadsheet
predicting that Gimbels will never go bankrupt, and
therefore its bonds are a good investment. I suggest to you
that Lotus is not liable for the debts of Gimbels.
Free legal advice is worth every penny you paid for it.
--
Fred Hopengarten K1VR
Six Willarch Road * Lincoln, MA 01773-5105
home + office telephone: 617/259-0088 (FAX on demand)
internet: k1vr at k1vr.jjm.com
"Big antennas, high in the sky, are better
than small ones, low."
>From n3rr at cais.cais.com (Bill Hider) Thu Feb 8 22:03:51 1996
From: n3rr at cais.cais.com (Bill Hider) (Bill Hider)
Date: Thu, 8 Feb 1996 17:03:51 -0500
Subject: Tower Help
Message-ID: <199602082203.RAA29732 at cais.cais.com>
I disagree with K7LXC's comment re: 40M element. I have used an A-4 with 40
M element since 1985. It's at 55 ft and it plays like gangbusters compared
to a 40M dipole.
The key is the rotatability and the null off the ends of it, not the gain.
Of course it doesn't have the gain of a dipole, but these other two
attributes more than make up for that. It's not gain that you need, it's
the ability to point the antenna at the station you're talking to (or trying
to talk to) and provide some rejection in the other directions. A single
fixed dipole just don't do that (except in two directions). Especially if
you don't have the supports for multiple horizontal dipoles and a switching
arrangement for them!
If you have an A-3 or A-4 you already have the rotating base for the 40M
element. If you then have the space to rotate it, it works FB! (My
experience only).
By the way, the Cushcraft catalog specifies the sq ft wind load of the 40M
kit. I don't remember what it is right now.
73!
Bill, N3RR
PS: I have NO affilliation or other relationship with Cushcraft or any other
antenna manufacturer. These comments are my own opinion based upon my
experiences.
Bill
At 03:02 PM 2/8/96 -0500, K7LXC at aol.com wrote:
>In a message dated 96-02-08 13:45:52 EST, you write:
>
>> How do you determine the sq. ft. wind load of an
>>antenna? I have a Cushcraft A3, and I'm thinking of adding a 40m kit to it
>>when it goes up (probably this summer). I can't find anything in the
>>specifications that defines the wind load.
>>
>>Is there some simple calculation for this? This this the aerodynamic flat
>>plate equivalent?
>>
>>Thanks.
>>
>>Bill Coleman, AA4LR
>
>Hiya, Bill --
>
> There's a long answer and a short answer. The long answer is to get Dr.
>Dave Leeson's (W6QHS) book on yagi design and crank through cylindrical
>multisection modulus, moment and other various calculations. The short
>answer is to get the manufacturer's catalog -- it'll be listed in the specs.
> If you want one publication that has all of the antennas, rotators plus
>various other products complete specs, pick up a copy of the CQ Antenna
>Buyer's Guide; it's a good reference for lots of specs. Contact your local
>dealer or call CQ direct for the latest copy.
>
> Regarding the Cushcraft 40M add-on kit, it's got negative gain compared to
>a dipole; put up the dipole instead if possible.
>
>
>73, Steve K7LXC
>
> "Up The Tower" now appears in CQ Contest magazine
>
>From Jeffrey Clarke <jdclarke at freenet.columbus.oh.us> Fri Feb 9 01:37:54 1996
From: Jeffrey Clarke <jdclarke at freenet.columbus.oh.us> (Jeffrey Clarke)
Date: Thu, 8 Feb 1996 20:37:54 -0500 (EST)
Subject: HELP !!! Sprint Team members needed
Message-ID: <Pine.3.07.9602082054.A15728-a100000 at acme>
Boy .... It is sure tough to put a team together ! If anyone needs
a team we still have 3 slots available on the MAD RIVER Team. right
now I have kw8n, k8cc, k8mr, nf8r , w8fn , k3jt , and ku8e (at wm4t).
lost 2 guys this week to family obligations ! SO.... if you are going to
be on e-mail me by tomorrow evening (deadline for n6tr)
Thanks in advance ,
Jeff KU8E
******************************************************************
* Jeffrey D. Clarke jdclarke at freenet.columbus.oh.us *
******************************************************************
>From Dave Lawley <101332.232 at compuserve.com> Thu Feb 8 22:13:15 1996
From: Dave Lawley <101332.232 at compuserve.com> (Dave Lawley)
Date: 08 Feb 96 17:13:15 EST
Subject: RSGB Topband Contest
Message-ID: <960208221314_101332.232_GHW93-1 at CompuServe.COM>
A reminder that this weekend is the RSGB 1.8MHz CW contest, 2100z 10th Feb
to 0100z 11th Feb. Overseas stations work UK only, and score 3 points per
QSO plus 5 point bonus for the first QSO with each county. Send RST and
serial number. UK stations send RST, serial number and three-letter county
code. A list of codes is given below, which will be used throughout 1996. Local
government reorganisation means that a different county code system may be
needed in future years.
You can email your logs to me (101332.232 at compuserve.com) please give
usual QSO data including points claimed for each QSO, and provide a summary
with the usual declaration.
CU in the contest.
73, Dave G4BUO
County codes:
ALD CHS DHM GUR JER NOR SOM WKS
ATM CVE DFD GWT KNT NHM SFD WIL
ARM CLD ESX GDD LNH NLD SCD WMD
AVN CNL FMH HPH LEC NOT SFK WLT
BFD CBA FFE HWR LCN ORK SRY YSN
BRK DYS GNM HFD LDN OFE SXE YSS
BDS DVN GNS HLD LDR PWS SXW YSW
BUX DOR GNW HBS LTH SPE TYS
CBE DWN GLR IOM MCH SRK TWR
CTR DGL GRN IOW MSY SLD TYR
>From Steven Sample <aa9ax at iglou.com> Fri Feb 9 04:12:18 1996
From: Steven Sample <aa9ax at iglou.com> (Steven Sample)
Date: Thu, 8 Feb 1996 23:12:18 -0500 (EST)
Subject: Comparison TS-870 & IC-775
Message-ID: <Pine.SOL.3.91.960208225606.17808A-100000 at iglou>
Had a little fun in the CQWW 160 CW multi-op'ing with NJ9C at his QTH.
We put several radios on for comparisons, including A-B receiver tests, etc.
I've recently noticed several people trying to get comparisons, so...
Mine is not scientific, but it's SHORT!
The 775 has the 870 beat hands-down in the receiver department. It's the
traditional problem Kenwood seems to always have - a high noise floor and
apparently wider skirts on the filters. The 775 is a much quieter radio,
and the filters are crisp and clean. The 500 hertz filters in the 775
provided more rejection than the 400 hertz filters in the 870. There
were other little nit-picky things that gave the 775 additional "edge"
over the Kenwood, but it didn't take a rocket scientist to determine the
most pleasant radio to use in a contest.
Steve / AA9AX
>From Robert <w5robert at blkbox.COM> Fri Feb 9 00:03:01 1996
From: Robert <w5robert at blkbox.COM> (Robert)
Date: Thu, 8 Feb 1996 18:03:01 -0600 (CST)
Subject: 8875/8874/MLA2500 ?
Message-ID: <9602081803.aa17508 at blkbox.COM>
MLA2500 owners, etc....
Has anyone tried a 8874 in place of the 8875?
--
73 Robert WB5CRG w5robert at blkbox.com
>From Ellen White <0006955216 at mcimail.com> Thu Feb 8 22:44:00 1996
From: Ellen White <0006955216 at mcimail.com> (Ellen White)
Date: Thu, 8 Feb 96 17:44 EST
Subject: test msg
Message-ID: <15960208224451/0006955216PJ4EM at MCIMAIL.COM>
this is a test msg de w1cw
>From okanep at iol.ie (Paul O'Kane EI5DI) Fri Feb 9 09:46:16 1996
From: okanep at iol.ie (Paul O'Kane EI5DI) (Paul O'Kane EI5DI)
Date: Fri, 9 Feb 1996 09:46:16 GMT
Subject: RSGB Topband Contest
Message-ID: <199602090946.JAA20468 at GPO.iol.ie>
If you need a contest logger specifically designed
for both sides (UK or DX) of this contest, you can
download SD from http://www.iol.ie/~okanep/ or
anonymous ftp from ftp.iol.ie/users/okanep/sd.zip
SD is shareware, and is fully working and unrestricted.
It's also good for ARRL DX, RSGB 7 MHz, CQ 160m.
73,
Paul EI5DI
>From Joe Subich" <subich at ramlink.net Fri Feb 9 03:30:48 1996
From: Joe Subich" <subich at ramlink.net (Joe Subich)
Date: Fri, 09 Feb 96 08:30:48 +0500
Subject: 8875/8874/MLA2500 ?
Message-ID: <9602091338.AA0030 at hun25.ramlink.net>
On 2/9/96 you wrote:
> MLA2500 owners, etc....
> Has anyone tried a 8874 in place of the 8875?
There is a major difference between the 8874 and 8875. The '75 uses
trasnverse cooling where the '74 uses axial cooling. To change the
tube would require major mechanical changes to pressurize the area
under the chassis and build a chimney for each tube. The chassis is
quite open aproximately the front half in the RF side) and the bottom
of the case have a great many vents.
The mechanical changes necessary to convert the MLA-2500 to use 8874s
would amount to almost a complete rework of the packaging ... and even
then the electrical problems (driving impedence, grid metering,
improper plate circuit Q on some bands) would remain.
73,
... Joe Subich, AD8I
<subich at ramlink.net>
>From i4ufh at contest.dsnet.it (Fabio) Fri Feb 9 13:37:26 1996
From: i4ufh at contest.dsnet.it (Fabio) (Fabio)
Date: Fri, 9 Feb 1996 14:37:26 +0100
Subject: IARU 95 Results Query
Message-ID: <9602091337.AA04544 at maggiore.dsnet.it>
Hello Guys,
Does anyone can reply me the top 5 results with QSO/MULT/SCORE of the IARU 1995
multi/single category, published in the February QST issue ??
I am looking for the IR4T results / published score, we receive the QST issue
after two month !!
Thank's de Fabio I4UFH
one of IR4T IG9R
i4ufh at contest.dsnet.it
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