I use an Icom 7300 with a Elecraft KAT500 tuner and Elecraft KPA500 amplifier with 2 antennas. Antenna 1 is a tri-band yagi for 20-15-10, and Antenna 2 is a multi-band dipole for 80-40-30-17-12-10-6. The KAT500 is configured to automatically switch to the correct antenna when changing bands. The automatic antenna switching comes in handy when controlling the station remotely with RemoteTx.
Switching bands and tuning:
Unfortunately the KAT500 does not get frequency information from the IC-7300 as it would from an Elecraft K3. For this reason you cannot just change bands and press the tune button on the 7300. The KAT500 will not know you have changed bands and will try to tune from saved settings on the wrong band. The trick is that the KAT500 requires that you send a short 10-20 watt transmission after you have changed bands on the radio to alert it you are changing bands. You must do this before you re-tune with the Icom tune button. If you press the tune button immediately after changing bands, the KAT500 will try to tune as if you were still on the last band and antenna and will try saved combinations from that band first as well as the antenna for that band. You may start tuning the wrong antenna. You must send a short manual RTTY signal first before you press the tune button.
Normally to send a tune signal with an Icom 7300 you change the mode to RTTY, reduce the power and press the transmit button or key the mic. You then have to switch back to the mode you were using.
A Better Way to send a tune signal:
See Videos Below
The Icom 7300 can record transmissions to it’s sd card. If you record a short RTTY transmission to the sd card it saves it as a wave file in the Voice folder. This can be copied into the area of the sd card that stores Voice Tx messages that are assigned to one of the voice tx buttons. Then you can just press a saved voice tx button that has a RTTY signal recorded without switching to RTTY and back.
The setup procedure is as follows:
- Turn on the TX recorder so all transmissions are recorded to the sd card.
- Change to RTTY mode and send a 1-2 second (or longer) transmission so it gets recorded to the sd card.
- Unmount and remove the sd card and put it in your computer.
- Find the .WAV file of the RTTY transmission in the /IC-7300/Voice/<date>/ folder and copy it to the /IC-7300/VoiceTx folder and rename the file ‘voicetx1.wav’ .Copy From:
- Put the sd card back in the radio.
Trying it out:
Now when you select the VoiceTx menu, the T1 button will send a RTTY signal when you press it when you are in SSB mode. This will cause the KAT500 to detect the frequency of the signal and switch bands in preparation for the next tuning cycle which will now use the stored values for the correct band. See the demo videos below*.
Band Switching and Tuning videos:
Notice the RTTY pulse from the Voice Tx button T1 causes the KAT500 to switch antennas and the KPA500 to switches bands.
The order of 20-40-15-80-10-17-14, causes the KAT500 to switch antennas each time as seen in the top of the video.
You can see the KPA500 tracking the band change as well when the Voice Tx button is pressed.
*Videos were made with dummy loads so no QSO’s were disrupted.