A sequencer is the key to protecting those expensive microwave or other antenna relays from hot switching which destroys the contacts.
Antenna relay sequencer.
Sequencer with relays is a fast solution and you may to setup it within few tens of minutes.
It pulls in last time delay is set by r4 r3 and c2.
A sequencer ensures that the relay has time to switch before rf power is applied.
The are immune to rf electromagnetic field.
Several years ago i described 4 a fool resistant transceiver interface and sequencer which improved some of the shortcomings of previous.
But it can be used in any amplifier antenna scheme.
But it can be used in any amplifier antenna scheme.
There is an additional description of a sequencer in the 300w 23cm amplifier article listed on the left.
One output is able to sink up to 100v at several amps and the remaining 3 up to 40v at about 500 ma each.
Also on the pcb is possible to choice if relay on pcb is in on or off position.
Rl1 is held on by the current loop through d1 as the field tries to collapse.
All rf relays are capable of safely handling much more rf power than they are capable of hot switching without damage.
Upon release of control tx rl2 releases with only internal relay delays.
Having looked at many different solutions i found that the w6pql sequencer met my requirements the closest.
This solution giving lot of possibilities.
The s2 sequencers primary application is for vhf uhf transverter amplifier and antenna switching.
After rl1 antenna relay current reaches a value that allows contact transfer q2 will conduct.
But any relay is relatively very unreliable device delay is not constant humidity dust and temperature has bad impact to the life time and connectivity of contacts mechanical parts have limited durability.
View to open box with sequencer.
This applies current to rl2 the input relay.
The s2 sequencers primary application is for vhf uhf transverter amplifier and antenna switching.
Dcw2004b vhf sequencer the dcw 2004 b vhf sequence controller provides precise sequential controlled switching of a vhf power amplifier rig transverter and lna pre amplifier and also provides a remote feeding voltage for the super amp range of pre amplifiers via the coaxial cable.
I built the sequencer on basic copper strip board and added four relays and jumpers so that for each event i could either switch the line to ground provide 13 8v or in the case of the lna switch the 13 8v supply off.
An enable signal to the sequencer will produce sequential output commands to a rx relay a tr relay an amplifier and a transverter automatically plus a polarity change lockout.
Relay in each position is possible to setup for switching to on or off according of request.
This sequencer will handle up to 4 events.
