Well what’s a sequencer?

 

It is a system that switches everything in order so that your TX system cannot destroy your RX system or your transceiver.
In reverse order you will not have this problem but if your TX antenna is not detuned it can also affect the efficiency of your RX system.
Because I now have to start shifting more, my current system (link) is no longer possible and it would only make it more complicated.

After searching online for a while, I found an affordable solution that fits my budget and my needs.
It is a ready-made printed circuit board with 4 ports, you only have to install the necessary relays and of course also make a enclosures  for this system. (You will find those boards on E-bayand on this site

https://www.hf-electronics.nl/4-port-sequencer-board.)

They cost about 20 to 30€ without the relays.

  

My goals is to have a sequence  from TX to RX and vice versa.

 

The first thing that should happen when I press my “footpedal”
Taking the power off my RX system.
Detune my RX system via relays.
Preparing my TX antennas via relays to go into TX because they are detuned when I use the RX antenna.
And then finally switch on my PTT of the transceiver.

 

All this is done automatically with a certain delay so that everything is safely closed before you go into TX or RX.

 

Of course when going from TX to RX there is also a sequence.
Release the footpedal and your transceiver goes into RX.
The TX antennas are switched to ground.
The RX antenna is being tuned back

Power is restored to the RX antenna.

 

All of this happens in a fraction of a second.

You can also buy this ready-made, most brands have something in their range.
There are also plenty of schematic’s online that you can use to build it from scratch.

 

16/09/2020

First step is making a test setup.

I have already thought of how I should manage everything in my head but now I have to draw everything out.
My foot control should also be able to work normally without the sequencer running.
This seems useful if I need to run other tests in the future and also in the summer when I have no RX antennas in use.

Front view of the system

To make the front I use the software paint and after printing and fitting it I will laminate it.
The advantage is that you can easily drill your holes at the right place so that everything looks neat at the end.

 

 

This is how I will link everything to the sequencer.
Afterwards I will provide each connection with the correct name so that no errors should occur when connecting.

 

I'm going to label everything on the inside of the box so that I don't make any mistakes.
You see 2 times ptt but one is the input and the other the output.

In everything I make I try to make it as safe as possible with a fuse at the input of the 12v.
You will see that I do not use heat shrink tubing, but at the end I will make everything safe with liquid plastic.
All DC connectors are also filled with liquid plastic as you will know only to avoid short circuits

 

The relays I use are just simple SPDT relays that I still had in my junk box.

 

Almost ready to test, as you can see it is a tangle of wires maybe I should have a look at making a pcb board myself so that everything seems less chaotic.
Everything on the inside will still be attached with glue.

 

Will check again to get a better picture of the finished product.

You can see that it also has a bypass, the reason for this is that I always want to decide at any time what should or should not work in the sequence. In the summer months I don't have rx antennas and then I can operate everything manually without having to unplug everything.

 

How does all this work now.

You can watch a video that I have put on my facebook by clicking on this link

At the top left there is 1 main switch that turns the system on or off.
In the middle of the system you see 4 LEDs that turn on or off when the sequence starts.

Led 1 is called "power on / off RX, if this led is lit this means that the voltage to the rx antenna is interrupted. If this led is not lit, there is voltage on the rx antenna (9circle array).

Led 2 is called Tuning / detuning RX, this led is on until I press my foot pedal, as soon as this happens led1 loses its voltage and led2 starts to detune the RX antenna. As long as led 2 is on, my RX system is online and therefore not detuned.

 

Led3 is called tuning / detuning TX, this control the tuning and detuning system of all my TX antennas. When the led is off all tx systems are detuned when it is on TX antennas are ready for transmitting my signal.

Led4 is the last one in the sequence its called PTT, its the last one that will be online and the first to go offline.
This one is connected to my transceiver.

 

As mentioned above, I added a bypass to each sequence, the reason for this is that I only use the rx antennas for the lowbands. From 10 to 30m and sometimes also at 40m, I also use my tx antennas to receive. As soon as I turn the switch, the sequence continues to run but I can manually block the sequence.