TX delay for vintage station

[w1vtp]

Part of my design goal was to include a means to delay the Collins 32V1 (or my Viking 1) just a bit so that the antenna changeover and RX mute can happen before the transmitter goes to transmit.

Here is the result which included a Cramer 0.05 to 2 sec adjustable timer.  The result is excellent.  I can use this circuit for either the Collins 32V1 or the Viking 1.  In the case of the Viking 1 S2 is a two section switch so I have to have means to actuate both sections.

Al

[AB2EZ]

Al

Great! The important thing is that this configuration is working for you.

It's a little hard for me to completely understand your wiring diagram...

But let me make an observation:

It appears to me that the antenna relay will switch to transmit before the 32V1 transmitter turns on... which is, of course, what you want.

But I suggest that an even better approach would turn off the transmitter before the antenna relay switches back to receive.

The way that this is usually done (when using relays) is as follows:

The antenna relay will be activated (i.e. in transmit position) if either of the two sequencing relays (instant and delayed) is closed. I.e. by using diodes (if necessary) arrange the wiring so that if either sequencing relay is closed, the antenna relay will have voltage applied to it. Saying this another way, the two pairs of sequencing relay contacts for activating the antenna relay are in parallel

The transmitter will be turned on only if both sequencing relays are closed. Arrange the wiring so that the contacts from both sequencing relays are in series.

Best regards
Stu

[WD8KDG]

Can't say a delay/ relay sequencing is a bad idea. The question is: Is it needed at or near a 100 watt DC input level? One relay can't be connected to both the TX & RX at the same time given said relay contacts are adjusted correctly. Maybe I was lucky, ran a DX100B with nothing but a Dow-Key for years.

Want to keep the receiver input grounded a while until the antenna is connected via the relay could be useful?

Craig,

[w1vtp]

Can't say a delay/ relay sequencing is a bad idea. The question is: Is it needed at or near a 100 watt DC input level? One relay can't be connected to both the TX & RX at the same time given said relay contacts are adjusted correctly. Maybe I was lucky, ran a DX100B with nothing but a Dow-Key for years.

Want to keep the receiver input grounded a while until the antenna is connected via the relay could be useful?

Craig,

Most likely The additional circuit was not needed.  But I had this Cramer .5 - 2 second delay relay burning a hole in my junque box.  So, I consider this a science project - just to see if I could do it.  Secondary to the delay TX function, I get the required S2 split function I need for the Viking 1 so the circuit is a drop in place either 32v1 or Viking 1 and since the 32v1 is arcing and sparking, I thought using the viker1 would be a good fall back on since it's working. Gotta think about grounding the RX input in stand by.  Seems to work pretty good as is

Dunno how it happened but here are the other three pages that are in the PDF I did.  I blame it on lack of sleep

Al

[w1vtp]

Stu

Sorry about the confusion.  If you check the PDF,  that I somehow didn't upload in the first place, I used squared boxes with numbers to indicate the PTT relay.  The diamond boxes indicate connections to the barrier strip.  The numbers on the 0.5 to 2 second delay have no boxes around them.  

I get the 110 from the barrier strip on the back of the 32V1 (9 = 110 hot, 7 = 110 neutral).

Sorry it is confusing the function is that when I close the PTT for TX mode, the 12 volt coiled relay closes and presents 110 to the relay that is inside the square (my original antenna changeover box) and also to the 110 volt coiled delay relay.  The relay in the square also supplies a closure from  p5 and p4 which operates a linear should I want high power. The other section of that relay provides the path for the receiver and transmitter to the antenna.

Perhaps the take away would be that these little Cramer delay relays provide an excellent adjustable delay option and one should design for his own application.

I'm open for suggestions on the sequence from TX to RX. I agree with your suggestion and have applied that concept to my "E" transmitter.

Al

[AB2EZ]

Al

Okay on using the stuff that you already have on hand... including stuff that's in the junk box... waiting to be brought into service.

Up to now, to make a sequencer, I've used relays and RC time constant delays...

But, the approach (below) is really neat... whether you purchase a kit or build one from scratch.

As a capacitor charges, the increasing voltage across it passes through the four different threshold voltages (provided by a voltage divider chain); and four comparators turn on... one-by-one. When the capacitor discharges, the comparators turn off in the reverse sequence.

http://www.eham.net/reviews/detail/7489

Stu

[Opcom]

That brings to mind another possible scheme using a LED VU meter driver. Keying starts a voltage ramp. As the voltage increases towards max, relays are energized subsequently. The voltage divider of the VU meter comparators determines the individual delays. a way to use a junk box board to do a special thing.

[ka1tdq]

Thanks for posting the sequencer schematic Stu.  I'm still puttering with this single FET transmitter, and I was wracking my brain trying to come up with something that would turn the gate drive on before the drain voltage (and in reverse during key-up).  This will do it!

Jon
KA1TDQ

[wb6kwt]

The sequencer circuit shown above is available, as a kit, from w6pql.com. I have two of his kits here and they work great.

Bob

[KK4RF]

Gentlemen:
     Phil Salas, AD5X, designed a nice QSK sequencer/Transmit/Receive'Antenna Changeover/Receiver Mute, relay-based,  unit for Boat Anchor rigs. His article was in QST maybe a year and a half ago. I have built several of them and they work great. Far Circuits sells the circuit board for it for about 5 bucks. It will hadle a couple hundred watts. Maybe this would work for  you. 73s,  Marty, KK4RF