With Fran bearing down on us, where is the best direction to aim antennas
into prevailing possible gale force winds? I seem to recall that aiming yagis
at 45 degrees into the wind was the best bet. Any suggestions?
Thanks,
Will
>From jreid@aloha.net (Jim Reid) Thu Sep 5 22:12:26 1996
From: jreid@aloha.net (Jim Reid) (Jim Reid)
Subject: N4XM antenna tuner
Message-ID: <1.5.4.32.19960905211226.006eb064@aloha.net>
At 09:28 AM 9/4/96 -0400, you wrote to Paul Schader regarding
his defense of the cost/technology of his XMatch, Classic Lowbander
antenna tuner. Paul had written: .....the XMatch
>>"is an expensive low volume product using a state of the art innovative
>>circuit.
>>This circuit does everything, YES EVERYTHING, better. I have applied it in
>>a top quality way to the present main product. The circuit is unique and
>>yes it is patented in several countries."
Tom's question:
>"Isn't it just a reversable T network with a fixed capacitor in one leg?"
As Paul wrote, everyone is curious about something new, so I took
the cover from my XMatch Tuner, Classic Lowbander, and had a
look inside. Per my attempt at circuit tracing, I would say it is a
reversable T network, many variations upon which Paul has patented
back in 1986. And that is quite an impressive bank of 5kV capacitors
all paralled together!! And a BIG, dual section variable capacitor.
The inductor is a FB ceramic core job. The switch is a very impressive
piece of hardware, with a separate detent position locking apparatus!
To me, I think my tracing shows the inductor "hangs" between the
interchangable capacitor elements, one fixed the other the dual variable.
The roller tap of the inductor appears to go to chassis "ground" while
the other end of the inductor is left open, again, I think. It is a bit
difficult for me to trace the wires, as my eyes are no longer as they
once were. I have had retinal surgery on both of them, so don't take
my circuit description as gospel. I can't even use our simple shack
hand tools much anymore; would you believe my wife now does
solder jobs for me when needed!!!
>>Paul wrote:"1) I probably know what I'm doing."
>Tom, "In that case, maybe you can explain something that has been
bothering me. >Why is the case ungrounded except at two points then? This
destroys the ability
>of the cover to function as an RF shield."
But somewhere, I can't find it now both Lew McCoy, inventor of the
"Ultimate Transmatch", and the ARRL
have written that an antenna tuner does not need to be shielded. I
KNOW I have read that, but cannot find the reference. Even tried
looking in Maxwell's book "Reflections", but it has been written.
I guessed, perhaps wrongly, that an electrical contact between chassis
and cover at only one point is done to eliminate a shorted turn about
the tuner, which might be a factor operating on the top band, 1.8mHz.
My cover has only one non-insulated cover to chassis bolt. (Paul
got after me awhile back for calling them sheet metal screws; they
are not.)
Me and my 87A so far have experienced no problems with RF around
the operating position. The XMatch is sitting directly beside the 87A.
>>Paul, "This circuit will become the new world standard. The "Ultimate
Transmatch" circuit is sure to fade away. And you may be one of the
last to know why."
>Tom, "What is the big advantage that would cause this effect, since they
are both T networks?"
I am not certain of my circuit tracing, because the XMatch Tuner does not
tune the way the usual antenna tuner does! It takes very little turning of
the inductor tuning handle to get an excellent match, even on 160. With my
MFJ 3kW tuner, one had to crank the inductor handle a long time to
get close to a match. The variable dual capacitor is always nearly 60% or more
meshed, unlike the usual two separate variable capacitor tuner
behavior. I find the tuning is very precise, that is, you have
to tune slowly and carefually. I now use a hofi coax swich ahead of the
XMatch input connector. Now I can switch between rigs and also, optionally
to an MFJ antenna analyzer. With the analyzer I can always, quickly set
the XMatch to a perfect 1.0:1 match at any frequency at which I might want
to operate. The only problem is the finicky MFJ unit's tuning control; just
touch the tuning knob, and the internal oscillator of the analyzer may QSY
up or down 50 kHz! Mine is an early 247, so tuning may be easier with newer
models.
Tom, I am VERY pleased with my XMatch Classic Low Bander Tuner!
I managed to melt the plastic core of my old MFJ tuner while on 160 one
night! That won't happen with Paul's unit.
I made an attempt to measure the efficiency of the XM unit, but decided I
really didn't remember how. I have both Bird analog and the P-3000 digital
watt meters, but just could not seem to remember how to go about it!
I thought I could measure the input power, subtract
the output power, and the difference would be the internal loss. The
problem is determining the true input and output powers simultaneously
in the presence of reflections; with both the Bird and the P-3000 it is
possible to get a reflection reading, of course, but I am quite uncertain
about
the % accuracy of either of these units. Without that info, I don't know
if my data would have any meaning. Maybe it would, but I gave up
with out trying. Perhaps I should try anyway.
Well, enough. I like the unit and Paul's workmanship and support
when ever I have questions is outstanding.
73, Jim, AH6NB
>From jreid@aloha.net (Jim Reid) Thu Sep 5 23:04:19 1996
From: jreid@aloha.net (Jim Reid) (Jim Reid)
Subject: What is your Lat-Long?
Message-ID: <1.5.4.32.19960905220419.006740d4@aloha.net>
At 09:24 PM 9/3/96 -0700, you wrote:
> Point your browser at "http://tiger.census.gov";. This is the census bureau
tiger >mapping service.
Craig, This is super. I found the level of detail on these maps,
when zooming way in, to be astonishing in accuracy, even for
a rather remote island such as Kauai is! Out here, 1.0 arcsec
is about 118 feet at this latitude; or a little less than 12 feet per
0.1 arcsec. With these maps at that site, I could even spot my
antenna "tower" to within 25 feet or so in the backyard!
It seems to be at latitude + 21.91955 deg (+21 55' 10.6") by longitude
of -159.49819deg (159W 29' 53.48").
I was amazed to learn of a slight bend in our street, Lawailoa Lane,
of which I was not conciously aware until I viewed the highly
zoomed map of the roads leading in to this QTH. A much more
useful spotting tool for land sites that the dithered GPS signal can
now provide, for sure.
Thanks for the site tip!
73, Jim, AH6NB
On the Garden Island of Kauai
>From aa7bg@initco.net (AA7BG Matt Trott) Fri Sep 6 00:04:05 1996
From: aa7bg@initco.net (AA7BG Matt Trott) (AA7BG Matt Trott)
Subject: Where to point antennas in storm?
Message-ID: <199609052304.RAA25649@zeus.initco.net>
At 05:09 PM 9/5/96 -0400, you wrote:
>With Fran bearing down on us, where is the best direction to aim antennas
>into prevailing possible gale force winds? I seem to recall that aiming yagis
>at 45 degrees into the wind was the best bet. Any suggestions?
Will, This has been beat around a few times (no pun intended) and as I
recall it's a mixed bag. I was just re-reading W6QHS book and as far as wind
areas go, the boom presents quite a bit less area than the elements do. So
the boom 90 deg to the wind is the way alot of us do it in windy Montana
(70-80mph frequently).
Some arguments against this as I recall were that elements are easier to
replace than booms so some on the reflector within the last year or so
argued that if you don't have a stout boom, it might be better to point the
beam directly into the wind, however this creates more stress on the tower
as stated above in that the elements don't "shadow" each other so they do
indeed present more wind area.
At 45 degrees the antenna presents substantially more area to the wind than
the other two scenarios (0 deg and 90 deg).
I'm just regurgitating some of the tidbits I've read, heard, seen,
smelled,etc. But, it makes sense to me.
----------------------------------------------------------------------------
- AA7BG "Vanity upon vanity...all is vanity" --Ecclessiastes
-----------------------------------------------------------------------------
>From kg5u@hal-pc.org (Dale Martin) Fri Sep 6 00:28:35 1996
From: kg5u@hal-pc.org (Dale Martin) (Dale Martin)
Subject: FW: ARLB058 Comm emergency declared
Message-ID: <01BB9B58.4884A320@pm3-155.hal-pc.org>
With Fran bearing down on the east coast and Sprint coming up this weekend,
I felt it appropriate and advisable to send this to the reflectors (even though
3900+ kHz is not usually contest ground, there will likely be some Fran-related
activity above and below 3900).
73 and good luck to our friends in Fran's path,
Dale
kg5u
(OBS)
----------
From: w1aw@arrl.org[SMTP:w1aw@arrl.org]
Sent: Thursday, September 05, 1996 16:08 PM
To: QST
Subject: ARLB058 Comm emergency declared
SB QST @ ARL $ARLB058
ARLB058 Comm emergency declared
ZCZC AG38
QST de W1AW
ARRL Bulletin 58 ARLB058
>From ARRL Headquarters
Newington CT September 5, 1996
To all radio amateurs
SB QST ARL ARLB058
ARLB058 Comm emergency declared
The FCC has issued a voluntary communications emergency declaration:
All amateurs are requested to cooperate by recognizing the existence
of a voluntary communications emergency in North Carolina and
therefore relinquishing the use of frequency 3923 kHz plus or minus
5 kHz, for handling emergency traffic resulting from Hurricane Fran.
The FCC also issued a voluntary communications emergency declaration
for South Carolina, recognizing 3993 kHz plus or minus 5 kHz for
emergency traffic.
NNNN
/EX
>From cwman@juno.com (Fred W Hoffert) Fri Sep 6 02:28:10 1996
From: cwman@juno.com (Fred W Hoffert) (Fred W Hoffert)
Subject: contest calls
References: <1.5.4.16.19960905003531.0b675c56@fyi.net> <322EC540.7EA2@mo.net>
Message-ID: <19960905.172923.10142.0.cwman@juno.com>
On Thu, 05 Sep 1996 07:19:12 -0500 duerbusc@MO.NET (Joseph J. Duerbusch)
writes:
>Boy, I sure don't have any problems with "Brand-X" in the pileup's!
>
>I would never go back to my old call, WB0ALF, which is about as long
>as
>a box car number....
>
>
>Joe K0BX (Brand-X)
>St. Louis MO
>--
>Joe Duerbusch K0BX St. Louis MO
>jduerbusch@mdc.com at work
>duerbusc@mo.net at home
>
>http://www.qrz.com/cgi-bin/qrz_gifs?k0bx.gif
>
Thanks for the reminder, Joe. I've been racking my brains for a choice
new call and I had forgotten my old neighbor's call was available.
WB0ALF is kind of short though. Let's see... should I make that #25?
73.............Fred/WA0QOA
CWMAN...I'D RATHER WORK CW!!!
SOON TO BE KNOWN AS "THE HAM FORMERLY KNOWN AS WA0QOA"
>From bigdon@eskimo.com (Big Don) Fri Sep 6 01:18:21 1996
From: bigdon@eskimo.com (Big Don) (Big Don)
Subject: What is your Lat-Long?
Message-ID: <Pine.SUN.3.95.960905171514.12203D-100000@eskimo.com>
On Thu, 5 Sep 1996, Jim Reid wrote:
> At 09:24 PM 9/3/96 -0700, you wrote:
> > Point your browser at "http://tiger.census.gov";. This is the census bureau
> tiger >mapping service.
>
> Craig, This is super. I found the level of detail on these maps,
> when zooming way in, to be astonishing in accuracy, even for
> a rather remote island such as Kauai is! Out here, 1.0 arcsec
> is about 118 feet at this latitude; or a little less than 12 feet per
> 0.1 arcsec. With these maps at that site, I could even spot my
> antenna "tower" to within 25 feet or so in the backyard!
>
> It seems to be at latitude + 21.91955 deg (+21 55' 10.6") by longitude
> of -159.49819deg (159W 29' 53.48").
>
Big Don also had good luck with this. Am wondering if anyone with access
to GPS equipment could check Tiger_Census to see how well the two agree...
Big Don
http://www.wsu.edu:8080/~garya/uncle.html
|
