Contents :

A collection of thoughts, and my notes about experiments and ideas, technical or otherwise, connected to Amateur Radio, Satellite working and monitoring and other electronics.

Thursday, July 15, 2010

Update IC-703 500kHz

After having made a study of the IC-703 manual I see that there is a high pass filter in the TX path , cutting off at 1.6 MHz.
This is most probably for avoiding the IF frequency (455kHz) reaching the TX output.

A switch - switching in a 500kHz bandpass filter (alt 136kHz filter for LW) or bypassing the filter - would probably be possible, but the *tiny* SMD components at this place in the radio makes me think twice about making the attempt.

It *may* be possible to tap the signal out to an external amplifier, but then there is still 30mW out of the TX at 500kHz, so that could as easily be used.

Conclusion : 500kHz looks possible with the 703, but I doubt the internal filter mod is worth the risk of ruining a perfectly good TRX.

1 comment:

  1. Maybe bridging the high pass filter with a 500kHz ceramic resonator could solve the power issue....
    73, Joachim pa1gsj