I'll second the observation that there is absolutely nothing "wrong" with
buying stuff...buy the best you can afford and you will be glad of it...
unless you simply ENJOY building stuff, which is FB too.....
Now I gotta go down into the basement to make some light bulbs and safety
pins ........yeah, I know I could buy 'em, they aren't expensive and they
work well but ...but ....oh I don't know.....
73 & please excuse me ...
----- Original Message -----
From: "Michael Tope" <W4EF@dellroy.com>
To: "'towertalk'" <firstname.lastname@example.org>; "Jim Lux"
Sent: Thursday, November 18, 2004 3:33 PM
Subject: Re: [TowerTalk] 80m 4Square Comtek box
> Don't be ashamed of buying stuff, people. I just paid $65
> for a tuning pulser. I haven't taken the cover off, but
> odds are that its nothing more than a relaxation oscillator
> and a rotary switch (to control the duty cycle). Still my
> free time is in short supply, so I try focus on building
> stuff where I will learn something new as that has a
> potential return on investment and is more enjoyable
> that doing the same thing over and over again.
> Modifying equipment is also a good way to learn
> how it works and build up skills without actually having
> to layout every board and fab every little detail.
> 73 de Mike, W4EF.......................
> ----- Original Message -----
> From: "Jim Lux" <email@example.com>
> To: "'towertalk'" <firstname.lastname@example.org>
> Sent: Thursday, November 18, 2004 12:03 PM
> Subject: Re: [TowerTalk] 80m 4Square Comtek box
> > At 02:23 PM 11/18/2004 -0500, Tom Rauch wrote:
> > > > Actually, there is enough information in ON4UN's book for
> > >a
> > > > competent individual to build a hybrid style (quadrature)
> > > > phasing unit without much more than an MFJ-259B. Of
> > >course
> > > > a good scope and current probes would help if one wanted
> > >to
> > > > optimize the unit.
> > >
> > >By the time most people did all that, they would be better
> > >off just buying the Comtek. Retail parts aren't cheap or
> > >easy any longer.
> > I'll second that...
> > Let's see..
> > Knowing the values is easy. for 50 ohms, 3.8MHz, you want L=2.09 uH,
> > The schematic is simple, too.
> > Then, you can engage in a few hours of design time to find an
> > core and design the inductor. (remember, it has to handle a kilowatt)
> > The caps are catalog parts (although you need to make sure they have the
> > right current ratings, etc.), so it won't take long to find them.
> > Then, you'll need to select some appropriate relays, a decidely
> > process, since RF relays that handle a kilowatt are quite pricey, so
> > going to want to use some other kind.
> > Order everything (after rummaging through the junk box) you need.
> > I'd wag the parts cost at around $100-200 (but it could easily be
> > suitable non-surplus relays are probably $10 each in the catalog, the
> > will be fairly inexpensive, cores are a couple bucks, but you have to
> > consider things like enclosures, connectors, etc.)
> > Wait 2 weeks (because you can't really work on it during the week).
> > Now, spend some time winding that inductor, figuring out how to assemble
> > it, put it into a box, etc. It's probably a nice 2 day job. And, if
> > have the time and tools, it would be enjoyable.. a nice combination of
> > mechanical engineering and electronics.
> > But all the same, if you paid yourself something like $8/hr, you'd
> > spend 20 hours on the whole project, so the labor cost is $160.
> > That's a pretty unrealistic labor cost. Either you have the time to
> > on it, in which case the time is free, or you're busy with lots of other
> > things, in which case the time is infinitely expensive.
> > Hmm.. or, just buy the Comtek box for $350. Not a bad deal.
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
> TowerTalk mailing list
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
TowerTalk mailing list