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#11
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Are you guessing on this, repeating an OWT, or do you have first hand hard data?
Jim "Rob Turk" shared these priceless pearls of wisdom: -You may not want to do that. It works for COM but may not work for -transponders. They work on pretty high frequencies (around 1000MHz) and it -doesn't take much to shield such signals. The composit may not be a problem, -but your paint or even wet conditions may stop the signal from getting out. - -Rob - Jim Weir (A&P/IA, CFI, & other good alphabet soup) VP Eng RST Pres. Cyberchapter EAA Tech. Counselor http://www.rst-engr.com |
#12
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Jim
The Radom's we used in military were transparent to the radar frequencies. You couldn't just take a can of Krylon and paint them. If damaged, was a special way of repairing. There must be data available on effect of glass, cloth and paints, etc., on RF transmission/reception? I haven't taken time for a Google search but might be something amoung Radoms, RF attenuation, etc Hughes Aircraft, who made the fighter radar I used, might have some attenuation figures someplace if you can get to the right person. Have a good Turkey day out there in the land of Fruits and Nuts G .. Big John Know you didn't start thread but others will read this post and thread will go on and on and on............... On Wed, 26 Nov 2003 09:20:27 -0800, Jim Weir wrote: Are you guessing on this, repeating an OWT, or do you have first hand hard data? Jim "Rob Turk" shared these priceless pearls of wisdom: -You may not want to do that. It works for COM but may not work for -transponders. They work on pretty high frequencies (around 1000MHz) and it -doesn't take much to shield such signals. The composit may not be a problem, -but your paint or even wet conditions may stop the signal from getting out. - -Rob - Jim Weir (A&P/IA, CFI, & other good alphabet soup) VP Eng RST Pres. Cyberchapter EAA Tech. Counselor http://www.rst-engr.com |
#13
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Where or how did you come up with 8 foot? References Please
"Paul Lee" wrote in message om... AFAIK the tranponder antenna should be 8+ feet away from warm bodies. "Rich S." wrote in message ... "Paul Lee" wrote in message m... There is nothing wrong with the $22 one. Only for fast birds, you may want an aerodynamic shaped one. Composite projects can even build the $22 jobs into wings, etc. Hey! Don't forget us wood and fabric types. I was going to install mine under my seat, but then I thought about possible radiation effects on the family jewels. I mentioned this to my wife who poo-pooed my concern. So I put it under her seat. Rich S. |
#14
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Big John
shared these priceless pearls of wisdom: -Jim - -The Radom's we used in military were transparent to the radar -frequencies. You couldn't just take a can of Krylon and paint them. If -damaged, was a special way of repairing. Exactly my point. There is a tremendous difference between C and X band radar and low L band transponders. Making generalities such as the prior poster did without having done the work is the worst sort of conjecture. The answer is that you CAN take a can of Krylon of the correct mix and paint them. You can't take just ANY can of Krylon without knowing what you are doing. And the damage required baking to eliminate entrapped water before you glassed the damage. - -There must be data available on effect of glass, cloth and paints, -etc., on RF transmission/reception? Yes, and we did it for Bellanca when we designed their internal antenna system. Jim Jim Weir (A&P/IA, CFI, & other good alphabet soup) VP Eng RST Pres. Cyberchapter EAA Tech. Counselor http://www.rst-engr.com |
#15
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Man, I didn't intend to start a fight...
I think I'll just buy the TED from AS&S; they're $19.95 in their on-line catalog. I'll need other stuff, so the S&H won't hurt too bad. Thanks RAH denizons for the assist! Got one half of the 'boot' cowl cut, drilled, smoothed last night. I was a bit dismayed by the un-evenness from the shears (regular scissors-type, compound lever), but a lot of the waviness went away as I de-burred the edge with 320 sandpaper. It looks quite nice. Jon B. "Cy Galley" wrote in message news:Ke6xb.315272$Fm2.330421@attbi_s04... Where or how did you come up with 8 foot? References Please "Paul Lee" wrote in message om... AFAIK the tranponder antenna should be 8+ feet away from warm bodies. "Rich S." wrote in message ... "Paul Lee" wrote in message m... There is nothing wrong with the $22 one. Only for fast birds, you may want an aerodynamic shaped one. Composite projects can even build the $22 jobs into wings, etc. Hey! Don't forget us wood and fabric types. I was going to install mine under my seat, but then I thought about possible radiation effects on the family jewels. I mentioned this to my wife who poo-pooed my concern. So I put it under her seat. Rich S. |
#16
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"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 I have sufficient experience with frequencies around 1200 MHz. Those don't like their antenna's shielded by wet or painted surfaces. Transponders are just over 1000MHz, 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. 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. Rob |
#17
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"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 operating 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 paint 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 power 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 |
#18
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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 operating 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 paint 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 power 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 |
#19
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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 : |
#20
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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 : |
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