Question For Jim Weir

"W P Dixon" wrote in message:

Nothing About Electronics...I can relate. That is one reason I want to
experiment with building some things such as a radio. To get a better
understanding of them.

This is jumping into the deep end like you wouldn't believe..8-) A better
hack at some first time projects would be something around audio
frequencies or so. Better probability of success and likely something you
can actually use and enjoy. I am not trying to discourage you at all. But
there's a reason that there are so few "really good" RF guys around - they
live in a different world from the vast majority of day-to-day grunts who
are product designers/EE's cranking out widgets for the masses.

I was involved in product development for more than 25 years and
still hold purely "analog" guys (and "RF guys" in particular - as a
subspecies of the analog types) with some degree of suspicion 8-)...
and a fair amount of awe. You have to love it apparently, and you
have to really bust your nuts to master it.

But - it ain't "rocket science". It's "radio science". I don't know which
is worse...8-)............. I'm starting to dabble in it a little 'cause I
don't
have anything better to do - and because I've probably already
gotten as "twisted" as possible - and this can't make it worse.

YMMV - and it *will* - I promise...8-).....

Hey, thanks for the kudos! (I'll take anything I can get). I just (as in
2 weeks ago) quit my job with Hewlett Packard/Agilent, where I was a
Senior RF/Microwave engineer. I've been in the field for 25+ years, and
now it's time to be an A&P. I've been through the FCC, FAA, TSO, PMA
hastle, and would second the idea that a transciever is not the medium
for learning electronics (at least not if you really intend to transmit
with it). Decades ago RF design was slide rules and Smith charts, but it
has devolved to "plug and play" modules that any EE can make sing
together. The day of the 10 picofarad calibrated wet finger is
dead,(your finger may vary) or at least on it's last legs. But by gum,
if it interests you, do it! The world need inventive, curious people
just as it alsways has!

Netgeek wrote:
"W P Dixon" wrote in message:

Nothing About Electronics...I can relate. That is one reason I want to

experiment with building some things such as a radio. To get a better
understanding of them.


This is jumping into the deep end like you wouldn't believe..8-) A better
hack at some first time projects would be something around audio
frequencies or so. Better probability of success and likely something you
can actually use and enjoy. I am not trying to discourage you at all. But
there's a reason that there are so few "really good" RF guys around - they
live in a different world from the vast majority of day-to-day grunts who
are product designers/EE's cranking out widgets for the masses.

I was involved in product development for more than 25 years and
still hold purely "analog" guys (and "RF guys" in particular - as a
subspecies of the analog types) with some degree of suspicion 8-)...
and a fair amount of awe. You have to love it apparently, and you
have to really bust your nuts to master it.

But - it ain't "rocket science". It's "radio science". I don't know which
is worse...8-)............. I'm starting to dabble in it a little 'cause I
don't
have anything better to do - and because I've probably already
gotten as "twisted" as possible - and this can't make it worse.

YMMV - and it *will* - I promise...8-).....

Thanks for all the advice. I know it is probably beyond my electronic
capability but it sure is something I may try later on. I'll start out with
Jim Weir's Magneto Timer Kit and do some more projects that I may have use
for and just get alot of practice in. Who knows, before I die I may actually
build a decent radio ! Are there any other little electronic projects
that may be a good learning experience for me? Of course things for my plane
or tools/testers are of interest. I have no desire to build a robot or
crawling thingamybob.

Patrick
student SPL
aircraft structural mech

"W P Dixon" wrote in message
...
Jim,
Is it practical, possible and legal to build a radio for your own
homebuilt airplane? I can't see paying 1000 bucks for a panel mount unit
for a volksplane.

--
Patrick Dixon
student SPL
aircraft structural mech


Patrick,

For many reasons a homebuilt aircraft radio is a basket of worms best left
unopened.

The cheapest and easiest solution is a standard hand held aircraft
transceiver. They can be purchased for a couple of hundred bucks and work
well. Especially if you provide them with an external antenna.

A number of the guys around here have purchased the radio and the optional
alkaline battery holder. It is just a plastic box that fits onto the radio
so it is pretty cheap. Then they cut the bottom off the box just leaving
the attachment part with the contacts the make the connection from the
batteries to the radio. They wire this into the airplane on the panel so
they can see the face of the radio and punch the buttons when the radio is
slid onto the adaptor. Then they plug in the aircraft antenna with the
appropriate BNC or other antenna connector and they have an FCC certified
"panel" mount radio for their homebuilt.

Works great and is a lot cheaper than a regular panel mount. Plus, you can
disconnect the antenna BNC and slide the radio off the adaptor on the panel
and reconnect the rubber duckie and the original battery and use it as a
handheld as well.

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

"W P Dixon" wrote in message:

Thanks for all the advice. I know it is probably beyond my electronic
capability but it sure is something I may try later on.

For lots of folks kits are sometimes a great way to get started. You
might be interested in something like this:

http://www.ramseyelectronics.com/cgi...ction&key=AR1C

It's a pretty straightforward little airband receiver (single conversion,
manual/varactor tuning). It's cheap and hard to go wrong. There's also
*plenty* of room for improvements and customization while you're
learning and experimenting 8-)... You'll instantly learn about the value of
an antenna and what phrases like "selectivity" mean. There are many
small mods you can make and - even if you manage to toast it - easy to
fix and you're only out a few bucks anyway.

When you get bored with it you can stick it out in your garage or
workshop and listen to the local traffic - not *really* exciting, but beats
listening to "elevator music"...........8-)

Beyond that - there are *zillions* of widgets, tools and doodads you
can build (Jim's being among some of the more useful, BTW)...

Bill

"Rip" wrote in message:

Hey, thanks for the kudos! (I'll take anything I can get). I just (as in
2 weeks ago) quit my job with Hewlett Packard/Agilent, where I was a
Senior RF/Microwave engineer.

Wow! So - you must be *really* weird by now??! 8-).....

snip

Decades ago RF design was slide rules and Smith charts, but it
has devolved to "plug and play" modules that any EE can make sing
together.

Those days are coming back. All the semiconductor makers are
obsoleting those "plug and play" modules so it's back to buckets of
discrete components if you really want to build something (and can't
afford custom silicon). Hmmmm.....I predict a lucrative second
career for you as a consultant if you want to stay in the game 8-)

The day of the 10 picofarad calibrated wet finger is
dead,(your finger may vary) or at least on it's last legs.

I always thought I could make a fortune if I could come up with a
solid state "finger simulator" - you know - something you clip on to
the rabbit ears so the family doesn't have to argue about who gets to
stand beside the TV and hold the damn things...8-) Everyone would
want one!!! Then along comes cable... sigh...

Bill

"Netgeek" wrote in
:


"W P Dixon" wrote in message:

Thanks for all the advice. I know it is probably beyond my electronic
capability but it sure is something I may try later on.

For lots of folks kits are sometimes a great way to get started. You
might be interested in something like this:

http://www.ramseyelectronics.com/cgi...ction&key=AR1C

It's a pretty straightforward little airband receiver (single
conversion, manual/varactor tuning). It's cheap and hard to go wrong.
There's also *plenty* of room for improvements and customization while
you're learning and experimenting 8-)... You'll instantly learn about
the value of an antenna and what phrases like "selectivity" mean.
There are many small mods you can make and - even if you manage to
toast it - easy to fix and you're only out a few bucks anyway.

When you get bored with it you can stick it out in your garage or
workshop and listen to the local traffic - not *really* exciting, but
beats listening to "elevator music"...........8-)

Beyond that - there are *zillions* of widgets, tools and doodads you
can build (Jim's being among some of the more useful, BTW)...

Bill




I assembled one of these several years ago. Your right about the
customization. It started by hooking the my o-scope's horizontal to the
tuning pot and rapidly swinging it through it's range, while listening, and
watching the audio on the vertical. I then could mark the known frequencies
around the pot's knob. OK, it's not extremely precise, but it sure did
show where the activity was. I then made a simple sawtooth generator to
drive the varicap, and the scope's horizontal input, and schazam!...an
"aircraft band spectrum analyzer". (I live less than 2 miles out on the
approach end of 12R at MSP.)

Ron Natalie wrote:
Vaughn wrote:

Practical? No. I have been in the radio business all my life and
I would not
even consider it, probably not even a kit.

Possible? Yes.

Legal? I don't think so.

Back a long time ago, in the first incarnation of RST, Jim actually
did
have a kit radio. The "legality" was dealt with by sending the radio

off to RST after you finished building it for it's test and alignment

stage. Jim has felt the market out for radios again a few times
over
the years, but it's a hard market.

Frankly, what I suggested to him maybe 10 years ago, and I think
would
still be intersting in pursuing is to have a com radio unit where the
radio parts were preassembled/certificated but with no real user
interface parts, just a digital interface of some sort that avionics
hackers could integrate with their own electronic panel.


Use a portable. Fasten it on the side of your cockpit and use
a headset.
I have flown gliders for hundreds of hours with a tiny portable on
a light
lanyard around my neck, but that may not work well over engine
noise.

I ferried my Navion around (it was between having the new panel cut
at
one shop and the radios installed at another) with my headphones, a
portable intercom and my Yazoo handheld. Worked passably (would
have
been better with a real antenna rather than the rubber coated dummy
load), but such would work well in a homebuilt.

Cabin noise you fix with a headset. The bigger problem with a lot of

these small planes is ignition noise. That can lay waste to the AM
signal in any radio.



************************************************** **********************************
Ron;

Back in 1983 I built one of RST's 360 Nav / Com radios. It was a fun
job with over 1000 parts on 9 circuit boards,as I remember. I sent it
back for calibration/certification and they found I had a couple of
diodes installed backward - otherwise OK. I flew our Rv-4 for 700
hours with it and a Communications Specialists handheld, with a
slide-in can and connections for power and antenna and wired into my
intercom.
Bob Olds RV-4
Charleston,Arkansas


************************************************** **********************************

"W P Dixon" wrote in message
...
Jim,
Is it practical,

No.


possible

Yes.



and legal

Yes.


to build a radio for your own homebuilt
airplane? I can't see paying 1000 bucks for a panel mount unit for a
volksplane.

You will spend a thousand hours designing such a device and ten thousand
dollars testing and certifying it.. But it IS possible.

Jim

That definitely seems to be the popular answer Jim. Thanks for your input.
May try the handheld contraption in my volksplane. Just would not want an
expensive radio in it . Now the Thatcher CX4 on the other hand

Patrick
student SPL
aircraft structural mech