----- Original Message -----
From: <towertalk-request@contesting.com>
To: <towertalk@contesting.com>
Sent: Wednesday, May 16, 2007 9:00 AM
Subject: TowerTalk Digest, Vol 53, Issue 62
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> Today's Topics:
>
> 1. Re: the elusive 1db (Wes Attaway (N5WA))
> 2. Re: inspection list (jacobsen_5@msn.com)
> 3. Re: What relay do Ameritron and Array Solutions (jeremy-ca)
> 4. Dayton Hamvention Amateur Radio & the Law Forum (Jim OConnell)
> 5. Re: Balun on LPDA (Bill Turner)
> 6. Re: Got a tower/antenna in a CC&R subdivision? (Bill Turner)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 15 May 2007 21:17:37 -0500
> From: "Wes Attaway (N5WA)" <wesattaway@bellsouth.net>
> Subject: Re: [TowerTalk] the elusive 1db
> To: "'Bob Nielsen'" <nielsen@oz.net>, "'TowerTalk List'"
> <towertalk@contesting.com>
> Message-ID: <003b01c79760$5fa93dd0$2801a8c0@office2>
> Content-Type: text/plain; charset="US-ASCII"
>
> That is a real interesting observation about that dish. I had
> some experience at Michigan State back in 1962-63 writing some
> Fortran programs and using IBM punched cards. I never saw the
> computer. In fact, I didn't really know much about how the
> computer worked. I just wrote some code, punched the cards, and
> put them into a steel drawer. The next day I would come back and
> see if the white-coated computer priests had given me a printout.
> It was touch and go, but finally I got some actual results.
>
> My guess is that someone actually did the math for the dish and
> wrote a program and ran it on a mainframe and came up with the
> design. It could be done .... it just took a little longer back
> then. But even then the computer was a lot faster than a slide
> rule, and a whole lot more accurate. Slide rules were great, but
> you were lucky to get within 10 per cent if there were very many
> calculations to make.
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Bob
> Nielsen
> Sent: Tuesday, May 15, 2007 8:25 PM
> To: TowerTalk List
> Subject: Re: [TowerTalk] the elusive 1db
>
> On May 15, 2007, at 3:02 PM, Pat Barthelow wrote:
>
> >
> >
> >
> > That elusive DB just reared it head at Jamesburg. We
> discovered
> > that our
> > dish has neither parabolas, or hyperbolas as part of normal
> Cassegrain
> > surfaces. Mike Brenner, our laser metrologist just determined
> that
> > the
> > dish, built by Philco Ford in Late 60s, probably designed in
> early
> > 60s was a
> > tweaked design that had reshaped both surfaces to gain only
> about 1
> > db more
> > in the 63 dbi gain dish.
> > I dont know why they went to all the trouble to do that to just
> get
> > one more
> > DB to listen to Geosynchronous Satellites.
> >
> > But a more interesting question, in light of the fact that this
> was
> > WAY
> > before the HP 35 was around , (;>) in fact in the REAL olden
> days,
> > Engineers used slide rules, and surveyors used 8 place trig and
>
> > Logarithm
> > tables. Logsin A minus Logtan B plus...oops...
> >
> > Anyone here from that era who might know if such a dish
> required the
> > computation horsepower of a mainframe of the time, to design
> and
> > build?
> > Say a bunch of Fortran Punch Cards and an IBM 360?
> >
>
> Maybe a bunch of grunts wielding Friden or Marchant calculators?
>
> I worked at Douglas Aircraft for a brief time in 1957 before
> going to
> college. My job title was "technical computer" and I had a nice
> but
> noisy Friden mechanical calculator on my desk to use in
> processing
> flight test data for the Navy A4 jet (which I had read from 35 mm
>
> film, their being a camera in the cockpit pointed at the
> instrument
> panel). After I had been doing this for a few months, my boss
> asked
> me to prepare some punch cards with the raw data, as they wanted
> to
> see if they could get one of their few computers (which belonged
> to
> the payroll department) to process the data (which I had already
> done
> manually so they would have something to cross check against the
>
> computer output).
>
> 73 - Bob, N7XY
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Tue, 15 May 2007 21:23:11 -0500
> From: <jacobsen_5@msn.com>
> Subject: Re: [TowerTalk] inspection list
> To: "towertalk" <TowerTalk@contesting.com>
> Message-ID: <BAY111-DAV1521C27A683CAD8875588B23C0@phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi guys and gals..... again....... on Franks' Tower inspection
list.............
>
>
> For some reason, from time to time, when ever I include a web address in
my e-mails, the link duplicates itself when it comes out thru the list.
Haven't figured it out yet. Works sometimes, other times it dups.
> Anyway, if your not clicking on the address contained in Franks, W3LPL
original post on the tower inspection, check it out and delete all that is a
dup at the end.........
>
> 73
> Jake K9WN
>
> ------------------------------
>
> Message: 3
> Date: Tue, 15 May 2007 23:18:24 -0400
> From: "jeremy-ca" <km1h@jeremy.mv.com>
> Subject: Re: [TowerTalk] What relay do Ameritron and Array Solutions
> To: <towertalk@contesting.com>, "Jim Lux" <jimlux@earthlink.net>
> Message-ID: <007f01c79768$df71f950$6500a8c0@KITTYMA123>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
>
> >
> > The VNA might take the guesswork out of some of the measurements, but
> > doesn't tell you much about how to change the design to make it
> > "better". And for using "non-RF" components in RF applications
> > (which is what most amateur market relay boxes are.. they are NOT
> > clever stripline designs like DowKey uses) there's an awful lot of
> > craft and art to the design, probably moreso than straightforward RF
> > circuit design. (Unless someone's been out building HFSS models for
> > relays).
>
>
> The VNA is simply a tool. As with any tool it requires that the user have
an
> understanding of its abilities as well as his own.
>
> The DowKey is not a stripline design, it is a coaxial line section; big
> difference.
>
> Commercial radio manufacturers have been using small open frame power
relays
> in RF use for over 60 years, nothing new there. Vacuum relays designed
for
> switching HV made an easy transition to RF.
>
>
> >
> > The VNA just tells you "good", "bad", or "about the same"... but
> > doesn't tell you "make the box 1/4" taller so the parasitic C is
> > less".. that comes from either mindnumbing analysis (probably a waste
> > of time) or good old empiricism (try a bunch of different ideas, and
> > see what works).
>
>
> Ive never had parasitic C problems at HF in a straight 50-75 Ohm layout.
> Amplifiers and even antenna tuners are another story. A lot of my work
> resume included millimeter wave
> circuitry up to and beyond 60 gHz; now THAT stuff is tricky! But you can
do
> a lot with
> RF absorbent material at microwaves and above
>
> After youve been around the circle a few times the old gut feeling is
> often the key to success if I may borrow an anology from my younger
> circle track racing days.
>
>
> >
> > And, a lot of what goes into amateur products (or pro products for
> > that matter) is non-RF related.. manufacturing cost, durability,
> > shipping, etc. all factor into component choices. I've seen
> > products (not in the ham market, and not RF related) that were
> > originally designed around the ready availability of a particular
> > surplus component. Then, when the surplus supply ran out, the mfr
> > had to go out and have custom parts made to duplicate a long
> > discontinued WW-II vintage part. That drove the Bill of Materials
> > (BOM) cost through the roof... especially for replacement parts for
> > the original widgets, and drove a completely new design.
>
> A lot of surplus parts from WW2 Ford and Willys built jeeps found their
> way into Kaiser civilian models.
> Heathkit started in business with WW2 surplus parts.
> I got my SWLing and later ham start with surplus from Radio Row in NYC
> back in the 50's.
>
>
> >
> >>When KQ2M operated my station 1987-95, I designed and built all of the
> >>elaborate stack switching and elevation steering for a 4 stack of yagis
on
> >>20, 15 & 10 as well as the pattern switching for 160 & 80 antennas.
Specs
> >>were so tight that amp tuning never changed even when several relays and
> >>networks were in the signal path. Performance was obvious in the contest
> >>scores.
> >
> > Just out of curiosity.. did those relay boxes work that well in the
> > initial design, or were there any design changes? Do you think you
> > might have just "gotten lucky" in the design and component selection
> > in the 80s?
> >
> > I've been casually measuring a variety of off the shelf relays over
> > the past year or so, and there's huge variations between seemingly
> > identical relay designs from multiple manufacturers.
> >
>
> I had already characterized numerous relays and had settled on new DPDT PB
> with dust cover 24VDC
> surplus units from All Electronics. They had more than adequate return
loss
> and isolation at 10M
> and below. Plus they were cheap, I think $2 each!
> And since they would be mounted in gutted CATV hardline boxes I liked the
> dust cover to
> minimize condensation here in NH.
> Since elevation steering was part of the array the VNA was a key in
> determining the
> built in phase delay through the various selections. With that determined
> it was then easy to
> cut the phasing cables to exactly what was needed. Since I was using all
75
> Ohm hard and soft line it
> was extremely advantageous that the company I was working for had the 75
Ohm
> option kit for the HP VNA.
>
> In the air performance was just as expected, no luck involved I hope! I
> could barely see the
> difference in grid current at any stack setting. This kept the LK780 happy
> (a very low production
> 2 x 3CX800A7 amp from Amp Supply) and the LK500 was always idiot proof.
> (KQ2M was one of the
> originators of the SO2R concept).
> Remember that I didnt operate those contests and the first design goal
was
> to NOT be woken up at 3AM to fix a
> sleepy operator induced problem!
>
> When Bob got married and bought his own place in SW CT I dismantled most
of
> the hardware.
> These days my interests are primarily 80/160 and then 6M and above; way
> above.
>
> Carl
> KM1H
>
>
> > Jim, W6RMK
> >
> >
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 16 May 2007 08:11:21 -0500
> From: Jim OConnell <w9wu@arrl.net>
> Subject: [TowerTalk] Dayton Hamvention Amateur Radio & the Law Forum
> To: towertalk@contesting.com
> Message-ID: <464B02F9.5040106@arrl.net>
> Content-Type: text/plain; charset=us-ascii; format=flowed
>
> Hamvention Amateur Radio and the Law Forum,
> Friday, May 18, 2007 Room 3, 12:45 p.m. - 2:15 p.m. Amateur Radio and
> the Law: Getting It Up and Keeping It Up
>
> Moderator: Jim O'Connell W9WU, ARRL Volunteer Counsel
> Speakers: Fred Hopengarten,K1VR; Author,"Antenna Zoning for the Radio
> Amateur".
> Brennan T. Price, N4QX, ARRL Volunteer Counsel
> Paula Uscian, K9IR, ARRL, Volunteer Counsel
> Tim Ellam, VE6SH, IARU Vice President;
> A discussion by Amateur Radio Attorneys on legal issues of interest to
> hams: How to avoid restrictive covenants and cc&r's, present your case
> for a tower permit, info on the latest court rulings on RFI, PRB-1 and
> towers. Updates on the ARRL's Legal Defense and Assistance Committee.
>
> 73, Jim O'Connell, W9WU
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 16 May 2007 08:33:49 -0700
> From: Bill Turner <dezrat@copper.net>
> Subject: Re: [TowerTalk] Balun on LPDA
> To: <towertalk@contesting.com>
> Message-ID: <gt8m431so2qihimuf1veecvatsdpa96u3q@4ax.com>
> Content-Type: text/plain; charset=us-ascii
>
> ORIGINAL MESSAGE:
>
> On Sat, 28 Apr 2007 00:07:22 +0200, "Peter Voelpel"
> <df3kv@t-online.de> wrote:
>
> >If you feed with open wire you have to convert to unbalanced 50 ohms at
the
> >other end, so using a balun at the feedpoint is preferable.
>
> ------------ REPLY FOLLOWS ------------
>
> How about using balanced line all the way with a balanced tuner at the
> shack end?
>
> It could be tricky to keep the balanced line from touching the mast or
> any part of the tower as the antenna rotates. Some careful planning
> would be needed there.
>
> Bill W6WRT
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 16 May 2007 08:51:29 -0700
> From: Bill Turner <dezrat@copper.net>
> Subject: Re: [TowerTalk] Got a tower/antenna in a CC&R subdivision?
> To: towertalk@contesting.com
> Message-ID: <ov9m43prfre120top33pi0tceompfl807c@4ax.com>
> Content-Type: text/plain; charset=us-ascii
>
> ORIGINAL MESSAGE:
>
> On Tue, 15 May 2007 17:57:51 -0700, "Tom Osborne" <w7why@verizon.net>
> wrote:
>
> >
> <snip>
> I really like the government getting involved in my
> >life, telling me what I can and can't do in my own house, inside or out.
> >More govenment meddling is just what we need in this country. 73
> >Tom W7WHY
>
> ------------ REPLY FOLLOWS ------------
>
> I don't think the government is involved in HOAs and CC&Rs, are they?
>
> Bill W6WRT
>
>
> ------------------------------
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
> End of TowerTalk Digest, Vol 53, Issue 62
> *****************************************
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