sequencer also for EME
Since my old sequencer has gone bad, I kept looking for a new one that should definitely have the function “TX inhibit”.
I use the Elecraft K3 as an IF radio with Transverter. Elecraft provides a TX INHIBIT line to Pin-7 of the ACC jack. You have to select either INHIB = HI or INHIB = LO to turn it on. I use the HI option and turn on/off the transmitter with a control voltage of + 5V from the last stage of the sequencer. That will protect your LNA for sure. Since I use this I never got a defective LNA by hot switching.
During my research I came across the company Hamtech from Hungary. Hamtech offer a sequencer HSQ5-EME-5V specially designed for using TX inhibit (it can be used without this option) and EME operation. EME in that case means switching the H/V plane relays from your Xpol antennas direct from the sequencer. I got in contact with Pali/HA8YU the owner of the company and picked it up at the Hamradio fair in Friedrichshafen.
The sequencer has the following properties:
- Sequence time adjustable from 10-100ms
- PTT + LNA + 4 switching stages
- PTT over 12V or ground
- LNA power supply 12V directly possible
- LNA circuit freely selectable switched on in RX mode, LNA always on, LNA off
- TX inhibit freely configurable + 5V or ground for Hi / low inhibit
- Switchable for Xpol antennas horizontal or vertical
- Relay switchover in the TX mode is disabled (hot switching is thus excluded)
- Antenna relay voltage 12V or 28V
- Additional outputs to power the sequencer 12V / 28V devices.
The sequencer is not really cheap it costs ~ 250 € but it is a good investment in the radio system especially considering the special features and the sophisticated concept of the sequencer.