SM7UZY



Can I have a tuner button on a 35 years old IC-730?



April 2017


Yes you can!
Admit, it’s hard to tune you antenna with a old radio like IC-730. You need to lower you power, change to CW and send a tone. That’s hard..  what if you could just press a button, like on a modern radio. Here is how...

On a IC-730 it’s really simple. I decided to use the WRITE button because I never use it, and will never do. Then I have another switch (MEMO) for something else.

When I press the write button, the mode is switched off (no matter what mode you are in) and switches to CW. It disconnects the current power and switches to 5 watts, it sets in TX and activates the ”CW keynote” that gives a tone.

So... now you can easily adjust the tuner with a button on the radio without hard work.

A easy fix with four small relays and a some diodes.

I ”cheat” the machine with a few diodes so it does not shorten the ”active” mode when it switches to tune mode. The mode selector has a 4×5 breaking ability, so I hade too use two relays to the mode selector when one part goes through the logic table. The other is regular 8v control, so these three channels going via one relay.

Logic relay that controls 1 of the 4 mode levels. The second relay controls the TX switch and the CW switch separately.

One relay controls the RF-effect down to 5w and the other 3 of 4 mode levels. The big electric tape ”case” is rotary pot (next image) to fine-tune the line input signal to the REF level.

I also suited to rebuild my line input (you can run this radio from mixer directly connected to it). Now I built it to the MEMO SEND connector so I can take line in there instead. No loose hanging wires anymore. Phew! Previously I had rebuilt so I could use it with an external PTT that I connected to the former ALC connector. Now it suddenly became fun to use the 35 year old radio.

Features:
- Tuner button (CW mode, 5w, TX and key), which is also linked to the next point.
- Can control LDG auto tuner automatically with the tuner button = a button to set the antenna. Controlled via a 3.5mm cable connected to the LDG tuner (radio connector).
- Line in signal from mixer.
- External PTT to foot pedal