Here's my view of what happened:
1. Someone advises to just put the transponder antenna inside the frame.
2. I place a warning, basically saying there's more to it then just put it
in and forget about it.
3. Jim comes back and asks if I have any experience at all that supports my
warning, in a somewhat hostile way.
4. I respond that in my experience as ham operator I do have hands-on
experience working with this. I caution the group (not Jim..) that diagnosis
is harder than hooking up a cheap SWR meter.
5. Jim feels it necessary to dismiss my experience as bullsh*t, posts his
entire resume, posts his list of valuable equipment and bashes my spelling.
Nowhere did I say Jim was wrong. His 15.000 installed antennas certainly
prove it can be done. But that doesn't dismiss that an unknowing home
builder might make mistakes. The builder, or a follow-on owner may decide
it's fancy to put metallic paint on the plane. Or someone may think it's a
good idea to install an inspection hole next to the antenna, and use one of
these aluminum covers. Both will influence proper operation of the
transponder.
I think Jim's response is way out of proportion. I know Jim has plenty of
knowledge on the subject and I'm sure he'll agree that you can't just stick
the antenna anywhere you want without thinking things through. Therefor I
would have expected constructive comments from him, not all-out bashing.
Rob
wrote in message news
Rob, when you really done it, it ain't bragging.
There are thousands - maybe 10's of thousands - of Jim's antennas
flying. He wrote the book on hidden aircraft antennas. Your
information is might be a reasonable extrapolation, but his is
empirical.
On Thu, 27 Nov 2003 08:04:37 +0100, "Rob Turk"
wrote:
:Jim,
:
:I'm truely disappointed about your response. If this newsgroup is about
:showing off how big your dick is, go right ahead. I was under the
impression
:that the newsgroup was to discuss and provide help. None of the
information
:I gave is wrong, I provided a fair warning to think twice before putting
a
:UHF antenna enclosed inside a frame. You made it into a ****ing match. I
:admire the knowledge you have, but the way you display it makes me sick.
:
:Rob
The Netherlands, not a native English speaker, sorry for any spelling
:mistakes...).
:
:"Jim Weir" wrote in message
.. .
: "Rob Turk"
: shared these priceless pearls of wisdom:
:
: -"Jim Weir" wrote in message
: .. .
: - Are you guessing on this, repeating an OWT, or do you have first
hand
:hard
: -data?
: -
: - Jim
: -
: -
: -As a licensed ham operator
:
: Jesus. A ham operator? Those are the credentials you come to the table
:with?
:
: Amateur radio extra, first licensed in 1959. First 'phone with radar
: endorsement, 1960. BS-Physics (Microwave option) 1967. MSEE CGS 1983,
RF
: option. Pacific Southwest Airlines (1963-1967) avionics and radar
:technician.
: Teledyne Ryan Space Systems (1967-1973) Microwave Antenna Engineer.
:Founder and
: CEO RST Engineering, with a world class reputation for hidden antennas
in
: nonconductive structures (1973 --) with approximately fifteen THOUSAND
perating
: antennas in plastic/wood/fabric aircraft including one hanging in the
: Smithsonian.
:
:
: I have sufficient experience with frequencies
: -around 1200 MHz.
:
: How long has it been since you fell off the turnip truck, feller? The
ham
:bands
: at 33 and 23 cm are 10% or so away from the transponder frequencies.
Not
:too
: far away, but far enough.
:
:
:
: Those don't like their antenna's shielded by wet or painted
: -surfaces.
:
: First, the plural is "antennas", not the possessive. In the second
place,
:this
: is the first mistake of fact so far. That is just horsepuckey. Wet
and
aint
: won't make squat for difference. And I've done and retained the
:engineering
: data that says so.
:
:
: Transponders are just over 1000MHz
:
: 1030 and 1090 to be exact. Betcha can't tell me without looking which
one
:is
: transmit and which one is receive.
:
:
:
: , it's reasonably safe to assume
: -they are equally influenced. I'm not saying it will never work (fwiw,
:GSM at
: -900MHz works in-door), but I do want to caution people that there are
:many
: -variables involved that could make it not work.
:
: Yada, yada yada...
:
:
: -
: -Contrary to COM signals (118-136MHz) you can't use just any CB or VHF
:SWR
: -meter to check out if the antenna matches at these frequencies. With
the
: -transponder sending out pulses of 200+ Watts I wouldn't want to
gamble
: -having a bad SWR and seeing that power end up ruining the transponder
:stage.
: -Better be safe and put the $22 antenna where it belongs; Outside.
:
:
: Izzat a fact? Then I guess I'd best trash my $50k worth of RF antenna
:test
: equipment, because I surely wouldn't want to gamble my transponder on
:brothers
: Hewlett and Packard's equipment and the results derived therefrom.
:
: By the way, do the math before you post. That 200+ watts of
transponder
ower
: is peak pulse power. If you go through the calculation, you find that
the
: transponder output stage is running about 5 watts CW averaged over a
:couple of
: seconds or so.
:
: Now, to repeat what I've been telling my colleagues building airplanes
for
:the
: last 30 years...put the transponder antenna inside the plastic with a
:round or
: (better yet) octagonal ground plane, shield the sensitive parts of your
:anatomy
: with tinfoil, and go for it.
:
: Jim
:
:
: Jim Weir (A&P/IA, CFI, & other good alphabet soup)
: VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
: http://www.rst-engr.com
: