RadioBanter - View Single Post

October 7th 04, 12:26 AM

In article ,
(Brian Kelly) writes:

(N2EY) wrote in message
...
In article ,

(Brian Kelly) writes:

There are prototype board shops

...
They advertise all over the electronics trade publications and on the
Web. "It just ain't the same as real hombrewing." . .

Yeah, I know, but depending on yer timeframe, space, tools and tolerance
for
smells and such it may be cheaper/easier/quicker to farm it out.

Time and tools I have, the space is a question though. I was raised in
a machine shop, worked in refineries, chemical plants, textile mills
and had a darkroom. Odors are no biggie.

I didn't mean just *you*.

Agreed and trying to use SMT devices to homebrew compact complex
equipment really drives a stake in it.

There are those who can do SMT, of course. But the stuff requires yet
another level of tooling and skills.

Kills it for me.

SMT was designed to be easy to *manufacture* not repair or experiment with.

In the ancient times, you mounted the parts on a wooden base, then wired
it
up. Build a rig in an evening.

ME built a rig on a wooden base? You jest. Never in this world . . !
Aluminum or steel or forget it.

I've done it...

Point is, it was quick, inexpensive, easy and forgiving of errors

And when it's done it looks just like what it is, a POS.

Yep - Perfectly Ordered System.

Then came metal chassis and panels. Do the metal layout, the metal work,
mount
the parts, wire it up. Build a rig in a bunch of evenings.

SOP.

Yup but a lot more work than a piece o' wood

I'm willing.

Me too. Plus if you need shielding the wooden approach is out.

Given typical basement resources, I'll have my mechanical dial built and
calibrated before the other guy has his PC boards done.

Probably but it depends on whether yer talking Collins quality or
rubber-band quality mechanicals.

I figured that one out about 35 years ago:

WW2 surplus had lots of good parts. Among the very best are the integral
dial/reduction drives/capacitors found in ARC-5 rx and tx units, and the
LM/BC-221 freqmeters. All you need are adapters for the shaft and a new
dial.

Swords into plowshares. I never bothered with Millen and National drives
for
serious stuff.

Then you missed the boat.

No, I didn't.

As you know I'm more than just a tad
familiar with those old surplus drives. They were designed *seven
decades* ago for use in high altitude high vibration combat
environments.

Which makes them perfect for ham rigs.

Usually on fixed freqs. None of which has anything to do
with ham gear particularly today's ham gear. They're miserably slow
tuning *kluges* by any realistic measure.

I *like* slow tuning. How fast did you set the dial on the '847 for FD? 5 kHz
per turn?

Lookit all the "modern" HF rigs - they typically default to a tuning rate of
5-10 kHz/turn. I was doing that in my homebrew rigs 35 years ago.

The best Millen and National could do was a weenie 10:1. Miller came up with
that goofy 6:1/36:1 planetary that cost the earth and felt like mush.

A good BC-221, ARC-5 or LM cap will do the job better and for a lot less money
and grief. Real gear drive, low torque, nice dial, etc.

Was the S-line a "kluge"? Tuning rate was 20 kHz/turn, IIRC, and took the ham
bands in 200 kHz chunks. Covering 80/40/20/15 took 10 bandswitch positions and
10 xtals. Plus going across certain points on the same band (say, 3590 to 3610
or 7195 to 7205) took a bandswitch move and running the dial almost end to end.

I'll take my surplus, thank you very much.

I could build a complete DC
rcvr in the space one of those clunkers sucks up and it would have a
nice smooth tuning mechanism.

Be my guest. You can put it on a website, just like you-know-who hasn't.

Which is why you got the last of those I
had. I am not going to be the Last Dinosaur, that's your yob.

Oddly enough, ARC-5 prices keep going up but BC-221/LM prices are down.

OBTW - check out the prices on new rotary optical encoders of decent quality,
if you're thinking about a synthesized design.

Remember that you'll probably need one with a lot of slots/steps on the encoder
disk. For example, if you want to have a tuning rate of 10 kHz turn and want
the steps to be 100 Hz, you need a 100 slot/step-per-rev encoder. If you want
faster tuning rate without sacrificing resolution, you need *more* slots/steps.

How many junker BC-221s can I buy for the price of one good encoder?

The Type 7 uses a cap from a hangar-queen BC-221. 100:1 nobacklash
drive,
thermally compensated, extremely rugged cast frame, etc. Better than almost
anything in typical ham gear. Cost maybe $5 for the whole chassis, which
has
lots other good parts.

To get more dial spread, I made a dial drum from a piece of 6" plexiglass
tubing. Recycled, of course. Dial light/reflector assembly is inside the
drum
and shines through the plexiglass. You view the lighted dial through a
window
in the front panel.

To calibrate, I wound a piece of paper on the drum and marked it with the
aid
of my working BC-221. Then the raw paper was redrawn via CADD, the result
inkjet printed on a scrap of Mylar drawing stock, and the whole thing put
on
the dial drum. Works and I can read it in any light, with or without
glasses.

Steam locomotives and gas lamps still work too. I'm waiting for you to
announce that you're driving back and forth to the job in a 1937 Model
72 Terraplane.

What kind of light bulbs do most people use? Good ol' incandescents,
fundamentally the same as Tom Edison had more than 125 years ago. Biggest
changes were the use of inert gas rather than vacuum in the bulb, and tungsten
filaments. Both circa 1900.

Internal combustion engines, home construction, lots of others.

Sure he did. He had a cb set, for one.

Seems like he also had some green dot / yellow dot sorts of reddios in
addition to the CB rig. 100% Rat Shack and Moxon plug & play. Whatta
"homebrewer" . . .

You see what some folks pulled with those licenseless HTs down in Orange
County, FL?

Nope.

Coupla kids stole school HTs (dunno if they were green dot or yellow dot or
FRS/GMRS) and then said they were gonna blow up the school, shoot teachers,
etc. Both were over Len's 14 years of age limit. Both are in really deep stuff.

Sure, transmitting radios don't need licenses or training in proper use....

Yeah, I guess we had to have somebody "over there" reading the
repeater meters and locked in mortal combat with all those kamikaze
geishas in the joints in Tokyo. While I worked my way thru E school
back here on the home front. On my own dime.

Been there, done that - halfway, anyhow. One big reason I went to Penn was
the
nice Benjamin Franklin scholarship they gave me. Covered more than half of
the
cost per year. Also NDSL loans and a near-full-time job year 'round.

I took a different path and not only paid the full tab as I went along
via the job, I also had a nice wad in the bank and two years worth of
engineering experience at the end of my trek. No summers off though.

Me neither - summer and "breaks" were the time to pile on as many hours as
possible. No OT but even straight time was worth it.

Junior year was a trip - 5 engineering courses and working 35-39
hours/week.

That's ugly.

No car, either. Thank you SEPTA....

PRR MU-54s: 14 minutes flat from Aldan to 30th St.

but...but...they're OLD technology!

I run a LISP
rountine in Autocad to come up with the cross-sectional properties

Nice! But I prefer Microstation...

Lemmee know when you get yer home installation of Microstation to spit
out the plane and torsional moments of inertia of a tower section.

I can get that result in about 120 seconds.....

Here we go, I'm gonna hold yer feet to the fire on this one Micollis.
I'm gonna show up at your place with a .dxf of a random cross-section
on a CD and you find **all** of it's cross-sectional properties within
120 seconds or you pop for my Newtown Square Ale House wet roast beef
sammich.

All I do is email the problem to you and wait for the results. Then
Microstation does a format conversion....

You SLIME!

Serious spankage, huh?

I didn't say I could solve the problem, just that I could get the results!

I'll buy the RB without a bet.

. . . you got that right . . !

What's the beverage of choice with those sammiches?

73 de Jim, N2EY

......still missing the old Drexel Ale House in the Bond Shopping Center.......