[VHFcontesting] Setting up TE RF amp for use with a sequencer.

[nosigma at aol.com]

Terry,

Are you around Saturday late afternoon or Sunday?  I need to stop by,  pay you for the XVRTR and pick up the 432 per amp.

Ready to install the XVRTR, sequencer and PA's back in the Jeep.

Attached is a pic of the sequencer, terminal strip for interconnects and XVRTR selector switch.  Very happy with the results.  I hope to set up the station and try it all out Sunday.

Again, I cant thank you enough.

73
John
KM4KMU 
On Sunday, December 15, 2019 Terry Price <terry at directivesystems.com> wrote:
So i think I sent my previous email before reading this through, sorry about that!!
In receive, the amp output jack is connected through the T/R relays to the input jack. The RF sensing circuit comes from the input so **IF** there is a large amount of RF being coupled from one antenna to another, it is very possible that the amp may try to key if the jumper between 5 and 6 are left in. 
So the safe answer is to cut the jumper between pins 5 and 6. Removing the two diodes that rectify the RF into DC will also render the RF sensing non operational although a bit overkill.
Terry Price - W8ZNDirective Systems and Engineering703-754-3876

On Sun, Dec 15, 2019 at 6:30 PM John Young via VHFcontesting <vhfcontesting at contesting.com> wrote:


Taking pin 2 to ground turns on the PA with 5 and 6 still internally connected.  

However with 5 and 6 internally connected the rf sensing is still enabled which defeats part of the purpose of the sequencer.  The amplifier can turn on if RF gets to it even if the PTT ground to rf amp lead from the sequencer is not grounded.  

I have had my 991A on 6m buzz my 1.25m amp, same thing happened with the W4IY Elecraft on 6m in september.  If I had been using a hard keyed pre amp on 1.25m it would have been fried.

I opened up the amp and there is no obvious sign of the pin 5-6 internal shorting wire.  Maybe you have to cut a trace now?


Calling TE Tomorrow.

73
John
KM4KMU 
On Sunday, December 15, 2019 John Young via VHFcontesting <nosigma at aol.com> wrote:

The TE manual gives some simple instruction for hard keying the amplifier but out an abundance of caution I want to verify my understanding of them before I start cutting wires and adding relays.

The DEMI sequencer gives a sequenced PTT ground to enable the amplifier.  The TE  instructions are to cut the internal  shorting wire between pins 5 & 6 and then connect the PTT ground to pin 2.

To enable the RF amplifier the TE instructions are:  1) Connect pin 5 & 6 then 2) connect pin 2 to PTT ground.

My interpretation of these instruction are:
I need to use the PTT ground to close a relay that connects pins 5 & 6 and then use an output from this relay to close another relay that connects the PTT ground to pin 2 on the amplifier.

Is this correct?
Is there a better way?

73
John
KM4KMU 


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