rx antenna
04-21-2002, 03:42 PM
#3
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MINOR SCRATCH???
Short
What in the heck are you talking about "Minor Scratch"???
He (from what I understand) broke off some of his antenna.
What is the point of diddo-ing other answers???
How do you break something off and have a minor scratch????
Have you ever done this???
Do you really know what you are telling this man???
Geeze
DOC
What in the heck are you talking about "Minor Scratch"???
He (from what I understand) broke off some of his antenna.
What is the point of diddo-ing other answers???
How do you break something off and have a minor scratch????
Have you ever done this???
Do you really know what you are telling this man???
Geeze
DOC
04-22-2002, 02:17 PM
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BRAD
Well Brad,
I apologize if the Geeze offended you. It was not intended to offend, and frankly my first time for this to happen.
Next time I will use cheese! Unless of course cheese has some obscure biblical meaning.
Again I apologize
DOC
I apologize if the Geeze offended you. It was not intended to offend, and frankly my first time for this to happen.
Next time I will use cheese! Unless of course cheese has some obscure biblical meaning.
Again I apologize
DOC
04-22-2002, 09:29 PM
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DOC
ever since day one it seams your out to put me on the spot or yell at me? i dont know if your joking sometimes or what but i just come here to have a good time and share what knowledge i posses. now i am used to be yelling at 24/7, i ref soccer and boy i get enough yelling from the parents as it is. so can we make truce
04-23-2002, 04:32 AM
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Shortmann
Nobody is yelling at you.
Chill out. If I yell at you , you will know it.
Paranoia sometime sets in if you try to read more than what is there.
Your cool don't worry.
DOC
Chill out. If I yell at you , you will know it.
Paranoia sometime sets in if you try to read more than what is there.
Your cool don't worry.
DOC
04-23-2002, 12:58 PM
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Fastang
While I cannot answer you question with the knowledge of in or out.....I have always performed a range check with the antenna in.
This is a procedure (range check) that is the most ignored (including me).
Your "long" sentences don't bother me........I find them interesting.
I am a little paranoid about my verbage because of the "G" word I unintentionally
used.
DOC
This is a procedure (range check) that is the most ignored (including me).
Your "long" sentences don't bother me........I find them interesting.
I am a little paranoid about my verbage because of the "G" word I unintentionally
used.
DOC
04-24-2002, 03:00 AM
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Problems
H Rat No flame from here. You bring up good points. Sorry to say but I think most are very true. As a retired electrical engineer I know that gauge, size etc. can effect tuning frequency response.
Thanks for posting. Bkf
Thanks for posting. Bkf
04-28-2002, 10:30 PM
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LMAO
hey guys,
if you were in Oz you would get more then the "G" word.
For what it's worth RX antenna wire is cut to a fairly broad length to cover a range of different frequencies in use.
Otherwise each Rx would have a "tuned" antenna.
Personally if only 2 - 3mm is lost it will not affect the range of the RX but if you dought it then take it to a certified repairer and have it replaced. Cheap insurance.
Someone mentioned TX antenna colapased causing the module to heat up.
It sure will, most TX use what is called a "base loaded" antenna . The TX PA( power amp) stage can be loaded down with an incorrect impedence that causes signal to be reflected back into the TX PA stage causing heat buildup.
It is nothing to worry about if you do it for a short period of time but if left on for a fair while may cause PA components to fail.
blah blah and ETC
IS that the bell of beer o'clock tolling??
Ciao!
be good to each other, the one you insult may be your mother in law!
if you were in Oz you would get more then the "G" word.
For what it's worth RX antenna wire is cut to a fairly broad length to cover a range of different frequencies in use.
Otherwise each Rx would have a "tuned" antenna.
Personally if only 2 - 3mm is lost it will not affect the range of the RX but if you dought it then take it to a certified repairer and have it replaced. Cheap insurance.
Someone mentioned TX antenna colapased causing the module to heat up.
It sure will, most TX use what is called a "base loaded" antenna . The TX PA( power amp) stage can be loaded down with an incorrect impedence that causes signal to be reflected back into the TX PA stage causing heat buildup.
It is nothing to worry about if you do it for a short period of time but if left on for a fair while may cause PA components to fail.
blah blah and ETC
IS that the bell of beer o'clock tolling??
Ciao!
be good to each other, the one you insult may be your mother in law!
05-27-2002, 06:45 AM
#13
Problems
The antenna input circuit "tunes" the random wire antenna. The wire is not a tuned length but the input of the receiver is used to match the wire to the input of the receiver.
If you really want to be sharp you would tune the receiver input while it is in the plane and flying
. Not too practical but the circuit is very accomodating. A couple millimeters won't be noticed.
If you really want to be sharp you would tune the receiver input while it is in the plane and flying
. Not too practical but the circuit is very accomodating. A couple millimeters won't be noticed.
05-27-2002, 08:57 AM
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Problems
Hey LF: With out me getting my pocket protector out is their 36mhz and our 72mhz a different harmonic. as in 1/4 wave 1/8wave etc. you get the idea. Even though various wave length antennas could in theory be used would one made for that freq. be better? Bkf
05-27-2002, 10:37 AM
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Chopped Antenna
For my two cents worth I would have to say get a new antenna.
You really aren't sure what is damaged in addition to the chopped off end and what the radiation pattern is going to be. (Probably not much of a change but why chance it?) I feel its just poor practice to be flying anything that is not it the condition it was designed. Would you fly with one end of your propeller missing 5mm?
You really aren't sure what is damaged in addition to the chopped off end and what the radiation pattern is going to be. (Probably not much of a change but why chance it?) I feel its just poor practice to be flying anything that is not it the condition it was designed. Would you fly with one end of your propeller missing 5mm?
05-27-2002, 11:23 AM
#16
Problems
These are not super sharp high Q ultra tuned antennae .The 50mhz antenna is also 39 inches as is the 53 Mhz. The only difference is the antenna input circuit.
The installation in the plane could have far greater affect regarding the antenna tuning than 3 mm of length.
Of course you could replace it if it makes you feel better. Beware of wire that is not fine 39 strand wire , since common hookup wire may not stand up to the flexing as well as the OEM wire. You may wind up far worse off for your cautious efforts.
A single bladed properly balanced prop would be a very efficient prop ! I wouldn't fly with 1/2 mm too much clearance in the piston to cylinder ,the engine won't run !. BUT 3 mm off the end of the antenna will make no measureable difference in the received signal at all. Designs have latitude and the 3mm is easily covered within that latitude. There would be no measureable difference. If you COULD measure the infinitesimal difference there would be a 50% chance the signal would INCREASE. Depending on how the input was tuned. In fact component aging in the first year would make a far larger difference than that itty bitty 3 mm.
I use receivers that are far from the way they were designed,and have no problem doing so. Most designs are compromsed by cost and as such leave room for improvements that ARE measureable ! Any MAJOR change in the antenna calls for proper retuning the receiver to THAT antenna. Most receivers could stand retuning from the factory.
The installation in the plane could have far greater affect regarding the antenna tuning than 3 mm of length.
Of course you could replace it if it makes you feel better. Beware of wire that is not fine 39 strand wire , since common hookup wire may not stand up to the flexing as well as the OEM wire. You may wind up far worse off for your cautious efforts.
A single bladed properly balanced prop would be a very efficient prop ! I wouldn't fly with 1/2 mm too much clearance in the piston to cylinder ,the engine won't run !. BUT 3 mm off the end of the antenna will make no measureable difference in the received signal at all. Designs have latitude and the 3mm is easily covered within that latitude. There would be no measureable difference. If you COULD measure the infinitesimal difference there would be a 50% chance the signal would INCREASE. Depending on how the input was tuned. In fact component aging in the first year would make a far larger difference than that itty bitty 3 mm.
I use receivers that are far from the way they were designed,and have no problem doing so. Most designs are compromsed by cost and as such leave room for improvements that ARE measureable ! Any MAJOR change in the antenna calls for proper retuning the receiver to THAT antenna. Most receivers could stand retuning from the factory.
05-29-2002, 06:05 AM
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Problems
Fiery,
The Rx antenna is attached to a double tuned font-end which can comprise several RF coils, capacitors, diodes and transistor or FET. The RF coils used in conjunction with capacitors provide a narrow signal opening for the required signal to pass.
R/C manufacturers purchase several thousand RF coils from Toko ( there are other names ), for use in their Rx's. During manufacture Toko produce coils adjusted to give the highest "Q" value (voltage magnification stated by a number), leaving the R/C manufacturer to place Capacitors in Series and Parallel configurations to obtain the required R/C frequency.
Modern R/C Rx's are machine made and having to tune each one manually is an enormous task - time is money ! R/C manufacturers insall the pre-tuned coils matched with known capacitor values to give them the selected frequency for certain countries.
50Mhz to 72Mhz Rx's will have different RF coils than those between 27Mhz to 40Mhz. One coil cannot cover such a wide range of frequencies even when pulled by Capacitors.
R/C manufacturers found that a compromise of antenna length ( 39" ) along with selected front-end capacitors and coils would determine satisfactory Selectivity, Sensitivity and Range.
Try to keep the Rx antenna at 39" to give your Rx its best chance of serving you well.
Electronics is not an exact science, there is always some form of tolerance. Too much tolerance, like significantly reducing antenna length to an already tolerant front end, can spell disaster !!
Apologies for going on at length.
DavidO
The Rx antenna is attached to a double tuned font-end which can comprise several RF coils, capacitors, diodes and transistor or FET. The RF coils used in conjunction with capacitors provide a narrow signal opening for the required signal to pass.
R/C manufacturers purchase several thousand RF coils from Toko ( there are other names ), for use in their Rx's. During manufacture Toko produce coils adjusted to give the highest "Q" value (voltage magnification stated by a number), leaving the R/C manufacturer to place Capacitors in Series and Parallel configurations to obtain the required R/C frequency.
Modern R/C Rx's are machine made and having to tune each one manually is an enormous task - time is money ! R/C manufacturers insall the pre-tuned coils matched with known capacitor values to give them the selected frequency for certain countries.
50Mhz to 72Mhz Rx's will have different RF coils than those between 27Mhz to 40Mhz. One coil cannot cover such a wide range of frequencies even when pulled by Capacitors.
R/C manufacturers found that a compromise of antenna length ( 39" ) along with selected front-end capacitors and coils would determine satisfactory Selectivity, Sensitivity and Range.
Try to keep the Rx antenna at 39" to give your Rx its best chance of serving you well.
Electronics is not an exact science, there is always some form of tolerance. Too much tolerance, like significantly reducing antenna length to an already tolerant front end, can spell disaster !!
Apologies for going on at length.
DavidO
05-29-2002, 11:35 AM
#18
Problems
Like I said ,Plus or minus 3 mm , NO measureable or meaningful difference. Theoretically it has a 50% chance of IMPROVING the signal. If you really want to make a difference ,Tune the input and ALIGN the receiver when you first get it . I do , new receivers and every other year once in service. You will gain far more from proper tuning and alignment than you will lose from 3mm of wire.
FAR MORE !
Actually most manufacturers claim they factory tune for the center of the band . In that case if you are operating nearer the top half of the band the shortening should IMPROVE the signal (IN THEORY) .
Fiery has it right ,this ain't rocket science ! But if you are that paranoid by all means put a new piece of wire on.
If you are a bit more technically astute than paranoid TUNE THE RECEIVER , you will make a REAL improvement . After one year of use component aging has taken the receiver off peak far more than that 3mm some are fretting over
If you are still paranoid the only real wasy to save the plane involves not flying
FAR MORE !
Actually most manufacturers claim they factory tune for the center of the band . In that case if you are operating nearer the top half of the band the shortening should IMPROVE the signal (IN THEORY) .
Fiery has it right ,this ain't rocket science ! But if you are that paranoid by all means put a new piece of wire on.
If you are a bit more technically astute than paranoid TUNE THE RECEIVER , you will make a REAL improvement . After one year of use component aging has taken the receiver off peak far more than that 3mm some are fretting over
If you are still paranoid the only real wasy to save the plane involves not flying
05-31-2002, 11:30 AM
#19
Problems
" Just replace the antenna wire..."
Or if you really insist on being anal replace the receiver The mismatched antenna MAY have strained the input coil and unbalanced the resonating capacitator causing detrimental and irreversible disfigurment of something else we never understood !
The question was Hey guys!
I've got problems! I just busted a 3-5mm off my rx antenna. Is that gonna screw things up?
The answer is still
NO
Or if you really insist on being anal replace the receiver
The mismatched antenna MAY have strained the input coil and unbalanced the resonating capacitator causing detrimental and irreversible disfigurment of something else we never understood !The question was Hey guys!
I've got problems! I just busted a 3-5mm off my rx antenna. Is that gonna screw things up?
The answer is still
NO
05-31-2002, 04:04 PM
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FIXIT
Oh no !
Could this be a love connetion right here on RCO????????
Advice comentary:
Fixit........Have you ever watched a dog chase a car???
What would he do if he caught it?
Ladyflyer.......Have you ever experienced a dead glow starter???
I love to have fun!
Doc
Could this be a love connetion right here on RCO????????
Advice comentary:
Fixit........Have you ever watched a dog chase a car???
What would he do if he caught it?
Ladyflyer.......Have you ever experienced a dead glow starter???
I love to have fun!
Doc
08-21-2002, 01:38 PM
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rx antenna
Diode,
I am routing my antenna through a carbon fiber/kevelar fuse on my sailplane...I have about 12" sticking out the rear of the airplane...is this ok???
I have heard carbon fiber does not let the signal reach tthe antenna...
Please comment.
Thanks in advance.
Doc
I am routing my antenna through a carbon fiber/kevelar fuse on my sailplane...I have about 12" sticking out the rear of the airplane...is this ok???
I have heard carbon fiber does not let the signal reach tthe antenna...
Please comment.
Thanks in advance.
Doc
