by jcerne » Sat Sep 23, 2006 2:26 pm
Hi All,
This is my first post to this forum and I've been very impressed by the quality and quantity of the information posted. I have a Flyzone Red Hawk, which has a 3-channel Tx that appears nearly identical to the Ventura that started this thread.
Although there's no mention of it in the manual, my Tx has a coax port that looks like it carries the FM signal (puts out a 6V amplitude, 12V peak-to-peak, sine wave at 27 MHz). This signal looks the same as the signal I measure when I put the voltage probes directly on the antenna. I would like to try using my Tx with FMS using SmartPropoPlus, as described in this Forum, but have had little success so far.
I've tried putting this signal onto two different pc's with two different sound cards using the microphone port, but MS Sound Recorder shows no response. Perhaps I'm overloading the input to the card? Do programs like Sound Recorder show no signal when they're saturated? I've tried both mono and stereo 1/8" jacks. I've tried putting resistors ranging from 5kOhm to 50kOhm on the central conductor to act as a voltage divider, but have not been able to decrease the voltage at the sound card end substantially. My experience with electronics is at much lower frequencies, so I'm probably missing something here (like impedance matching, reflections, etc). The resistor was placed at the Tx end of the cable because that's where I'm attaching a mono coax cable.
As expected, when I run FMS, I just get noise in the channels.
If you have any suggestions, please let me know.
Thanks for your help,
John