Question For Jim Weir

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

"W P Dixon" wrote

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.

Yeah, I see a future Kitplanes article! g
--
Jim in NC

"W P Dixon" wrote in message
...
Jim,
Is it practical, possible and legal to build a radio for your own homebuilt
airplane?
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.

I can't see paying 1000 bucks for a panel mount unit for a
volksplane.

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.

Vaughn




--
Patrick Dixon
student SPL
aircraft structural mech

"W P Dixon" wrote in message

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

Absolutely agree! I've got a couple of receiver protos I've lashed together
and have been playing with. Great fun but not very practical. There are a
few cheapo kit receivers out there (e.g. Ramseyelectronics.com,
Hamtronics.com...) but not exactly "industrial" - and not adequate for
aircraft use. You could build something much better but the search for
decent components is a real hassle.

Possible? Yes.

Certainly possible (as noted above) but for a one-off you'll have way
more than the $1000 in it when you're done (and that's counting your
time at a mere $0.50 per hour 8-)....... Even then, you'll probably be
disappointed in the result.

Legal? I don't think so.

And this is the major rub. You can build receivers all day long and
pretty much do whatever you want with them (most of mine will
become paperweights!)... but then there's the transmitter! You'll need
lots of expertise and *FCC approval* - which is where the whole concept
comes to a screeching halt. Licensed hams can build their own
transmitters *for use in the ham bands* - but the FCC and FAA are
understandably concerned about what happens in the aviation bands.

The only "kits" I've ever seen were from RST and I actually built one
some 20 years ago. BUT - it stopped being a kit when you finished
the construction because, to be *legal*, it had to be returned to RST
for alignment, checkout and - most importantly - provision of the FCC
label that was then attached. Maybe Jim can enlighten us as to how he
managed to pull this off - and how much hassle it was...........8-)

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.

A reasonable "kit" might be something that made the handheld more
"permanent like" (tied in to the intercom, better audio, clean power, etc.)
but it would no doubt have to involve NO modifications to the portable
(or you're back to the FCC certifcation problems)...

Bill

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.

Yeah I worry about the small cockpit in the VP and just not having alot of
space to put things on the sides of the cockpit..after all there has to be
room for me in there too! I'd really like to have a panel mount. Not only
for the reason above but for better performance in general. I have not seen
any portable units installed using a real antenna to compare , just the
little rubber whip things that I do not like.

Patrick
student SPL
aircraft structural mech

"Ron Natalie" wrote in message

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.

This is exactly what got me started on my own project! What I really
wanted was a set of very small "modules" (e.g. Com, Nav, GPS, etc.)
that were "headless" black boxes. No user interface - rather a serial
(Rs232/422) or, preferably, CAN I/O scheme. Then the user control,
display, et. al. can be as simple or as sophisticated as you'd like.

Advantages are that the modules can be mounted anywhere it's
convenient while taking up very little space. The panel space needed
can be user selectable dpending on how fancy they want to get. And
the level of integration with other systems opens up some really
interesting possibilities.

Still working on it - but who knows if it will go anywhere. The
possibilities
are really intriguing however so I continue to bash on the things. In a
perfect world if I could get someone like Jim to collaborate and/or
critique the RF portions I'd be *very* tempted to move forward with
the FCC and other certifications. Surely there are others who could
use these widgets - particularly if the cost can be held to some
reasonable level. Would probably always be a niche market with
relatively modest volumes but that's fine with me.......8-) Already did
the big-ticket, high-volume drill for years and don't care to go back!

If anyone here has any comments or wants to get involved let me
know........

Bill

If anyone here has any comments or wants to get involved let me
know........

I know absolutely nothing about electronics, but I'm an expert at plastic
injection molds. Let me know if you need some help with your cases.

"LCT Paintball"

I know absolutely nothing about electronics, but I'm an expert at plastic
injection molds. Let me know if you need some help with your cases.

Great! Maybe we can start a grassroots movement to build widgets.
Drop me an email and maybe we can see how to get started.............
Aren't you the one in San Diego?

Bill

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. I am going to build Jim's magneto timer from his
Kitplane's article to start getting a feel for the stuff! I don't know why
it intimidates me so much but it DOES
Doing the schematic refresher , now finding all the parts for the magneto
timer. hey and buying and or building tools is always fun. LIKE A KID IN A
CANDY STORE!!!!!!!

Patrick
student SPL
aircraft structural mech