Simple RF amp for iphone FM transmitter?

gootee

Joined Apr 24, 2007
447
Randomly LENGTHENING an antenna would probably do more harm than good, if the antenna was competently designed, originally.

I believe that the suggestion was to try using an EXTERNAL antenna, not to lengthen the existing antenna.

You would also need a properly-matched controlled-impedance transmission line (e.g. a coaxial cable) in order to get good performance from an external antenna. And the external antenna would need to be optimized for the RF's frequency and the transmission line's impedance.
 

Thread Starter

rudyauction8

Joined Jan 27, 2012
250
Randomly LENGTHENING an antenna would probably do more harm than good, if the antenna was competently designed, originally.

I believe that the suggestion was to try using an EXTERNAL antenna, not to lengthen the existing antenna.

You would also need a properly-matched controlled-impedance transmission line (e.g. a coaxial cable) in order to get good performance from an external antenna. And the external antenna would need to be optimized for the RF's frequency and the transmission line's impedance.
I'm pretty sure a wrinkled strip of foil shoved in next to the circuit board is not a well designed antenna. I ended up running a 1 foot wire off of where the foil was attached and got the range I needed. As for harming the transmitter, it's only running about 1mw or less and has worked fine for quite some time now with the new antenna. If it does burn out, a new one is only $4 on ebay so I'm not worried.
 
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