RadioBanter - View Single Post

October 5th 04, 12:56 AM

In article ,
(Brian Kelly) writes:

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

(Brian Kelly) writes:

I've owned three CAD plotters. Two were early-mid '90s pen plotters
and both were abominations I never want to have to deal with again. My
current plotter is an HP D-size Windoze color inkjet machine which is
very nice. All of 'em are/were sheet and/or roll fed and can't be used
to draw on flat surfaces. You're talking about using a flatbed pen
plotter. I guess there are some of those still out there but I don't
want anything to do with 'em for any purpose much less just to crank
out a few PCBs.

R R R

There are also various techniques where you print a positive (?) onto a
transfer sheet which is then ironed onto the boardstock (literally) and
peeled off. Then etch.

THAT sounds like the way to go. This is good. Inkjet or laser printer?

I forget. Google rec.radio.amateur.homebrew for "DIY PC boards" "inkjet" and
such words. All sorts info the past few years.

Then the slickest trick of all:

There are prototype board shops that will make boards for you. You feed 'em
the
artwork and they make the boards in an almost totally-automated process.
Prices
are low enough that if you make a few copies it gets really attractive -
particularly since the price includes things like coating and component
locations. And you don't have to deal with the chemicals or board stock.

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.

Or just do a mechanical dial...

Why would I do that when shaft encoders and freq counters are a
helluva lot smarter way to go??

They're only "smarter" if you have all the goodies to go with 'em. Like the
whole synthesizer and the controller and the programming. For a one-off
project that gets to be a bit much.

Not my problem, those are your problems, I don't reinvent wheels, I do
the knob, you do the rest.

This is one of the trends that makes homebrewing unattractive.

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.

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

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

Then came PC boards. Do the metal layout, the metal work, the PC board
layout,
fabricate the PC boards, stuff the PC boards, mount the rest of the parts.
Build a rig in some weeks of evenings.

Then came PICS and other programmable devices. Do the metal layout, the
metal
work, the PC board layout, fabricate the PC boards, stuff the PC boards,
mount
the rest of the parts. Then do the software development, debug, program.
Build a rig in many weeks of evenings.

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.

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.

Right on the money. As if Sweetums ever sank dime one of his own wad
one into any "station he operated".

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?

Fact is that he wouldn't have done
any of it if us taxpayers hadn't paid him to do it . . . Hell, we even
paid him to trudge thru the University of Monmouth Vo-Tech Division.

So what? That's what it was there for.

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.

Junior year was a trip - 5 engineering courses and working 35-39 hours/week. No
car, either. Thank you SEPTA....

Where the disconnect occurs is in situations like this:

Len says there was no use of Morse Code at ADA. Or anywhere in US Army
"point-to-point" radio comms back in 1952 or whenever. All done by
RTTY...or
RATT, as they called it then. All of which is almost certainly true.

Where the disconnect occurs is that Len seems to think that the Army's
non-use
of Morse then and there means that hams should not use or have a test for
Morse
here and now. The connection is never explained.

Nobody can "explain" irrelevance compounded by irrationality. Or
explain him for that matter.

There is no way that any guy/gal even with the world's quietist rcvr
and offscale BDRs and IMD3s is gonna "coexist" and ragchew with
anybody on 7.020 at sundown and beyond during the two big CW DX
contests, just isn't possible in any even remotely practical scenario.
Try it the last weekend of November. Move up the band or go to 30M.
'Way up the band . . .

How far up does the contest go? How about 7.070?

Bunch of variables are involved in this sticky wicket. But in general
at high noon a QRP ragchew on 7.020 should be no sweat. But when the
east coast big guns swing their monster yagis at EU to open the band
in the afternoon you better be above 7.050 and the "MUF" goes higher
from there as the clock ticks. MUF in this case being the *minimum*
usable freq for non-contesters.

R R R

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....

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

I'll buy the RB without a bet.

73 de Jim, N2EY