Remotely controlling a rotary switch

[aafradio]

Just another thought, Don...how far is it from the shack to the tower?

Something like http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260574075127 might be another alternative if you're running your cables in plastic conduit.

Plenty of Ledex stuff on there as well.  Found this for $6, not sure if it's 33 degrees or not:

http://www.tradebuyerseller.com/electric-solenoid-/-ledex-/-new-/-nice-/-p.n:-7810/290376359342/12576/

[k7yoo]

Don: the relays are about $20 each including shipping from either the guy in the Ukraine or UR4LL in St. Petersburg. They will usually negotiate on a quantity deal. I think I have bought 20 or so over the past several years. Relays are easy to deal with and these even have aux contact to run an indicator light.
I can e-mail a link if you want to investigate further. I also have a multi wafer dc motor driven switch assembly that I purchased from a surplus place on a Korean trip if you want to try that. It was actually built for that purpose. I suspect it came out of some military equipment.

Dave: I think the chokes (static drains) are a 1 Mh. They look suspiciously like Valiant plate chokes !
The picture shows "version 1" and I have since rearranged the tuners. I don't have the room for decent antennas so I tune what I have at the feedpoint.
Skip

[k4kyv]

the relays are about $20 each including shipping from either the guy in the Ukraine or UR4LL in St. Petersburg. They will usually negotiate on a quantity deal. I think I have bought 20 or so over the past several years. Relays are easy to deal with and these even have aux contact to run an indicator light. I can e-mail a link if you want to investigate further.

What kind of contact spacing and voltage rating are these?  I can't really tell much about them from the photos.  I assume from the picture they are single pole, so two relays would be needed for each tuner output to line.  Are they single throw or double throw?  I need some with at least 1/2" spacing between open contacts, since some will be switching the high voltage point of open wire tuned feeders, the kind of thing for which you would normally use a big-assed knife switch (as I am presently using).  They would also need to handle several amperes of rf, since others would be switching the line at a high current point, as well as the input line from the shack at up to 3 or 4 amps or more, depending on tuner settings. It appears I am talking about a total of at least 20 relays (10 each if they are available in double pole).

 

I also have a multi wafer dc motor driven switch assembly that I purchased from a surplus place on a Korean trip if you want to try that. It was actually built for that purpose. I suspect it came out of some military equipment.

I might be interested.  How many poles and how many positions, and what kind of contact spacing?  What kind of insulation?

I may just stay with manual switching to change bands, and gang all the variable tuning caps together with the reversible motor so that I can at least make a  major QSY within a band without a trip to the  tower.

Another problem with the switches I have is that they are not constructed with the shaft extending rearward so you can gang them end to end.  I had planned to couple the front shafts together and turn them with a National 90° right angle drive, similar to the tuning capacitor configuration using the worm drive in the HRO.  That way, I can gang one two-wafer switch that selects the tuner to the line from the shack (now coax but maybe later open wire line), to the other to select which tuner feeds the open wire line that goes up the tower, but I still need another switch to select either the open wire line that goes up the tower to the horizontal dipole, or the single wire that attaches to the base of the tower to form the vertical.  I have a couple of additional identical wafer assemblies, but mechanically coupling one of those to the assembly just described would be a Rube Goldberg mechanical nightmare that would probably be flaky even if I initially got it to work.

[w3jn]

Don, I have a bigassed TMC remote tuna that has a motor driven rotary switch.  Here's how they do the indexing:

There is a disc on the same shaft as the rotary switch with a cam profile.  The dips in the cam correspond to the switch stop positions.  A microswitch senses when the shaft is at the dip, and shuts the motor off.  To start the motor, there is a pushbutton back at the control box in parallel with that microswitch - once you get the motor started, the cam profile is such that the motor then keeps moving until it hits the next dip.  So you just momentarily hit the button to advance the switch one position, or hold it down to keep it moving.

One section of the rotary switch has a resistors, wired so they are progressively in series.  A regulated DC voltage is fed thru them, to a milliammeter on the control box so you can see what position the switch is in.

Of course you'll have to remove the switch detents.  The only real tedious work required is to machine up the cam disk and get the microswitch aligned correctly.

[aafradio]

I like that!  Don could use one of the existing detent cams on either of the two switch assemblies.  Just mount a microswitch with a roller on it where the spring assisted detent follower currently resides.  You will still need a small added wafer to tell you which position the switches are in using an array of small lights or LEDs in your control panel.  Great idea, John!

[KM1H]

Bird made some motor driven rotary coax switches using the cam and microswitch method.

Ive also seen stepper driven big Variacs.

With access to a machine shop anything is possible.

Carl
KM1H

[WA1GFZ]

It doesn't need to be a cam with a detent it coulld also be a disc with say allen cap screw heads to catch the microswitch. Just allow enough slop in the system so the switch lands in its own detent when the moror stops

[k4kyv]

Thanks for all the ideas so far.  I have some n.o.s. microswitches somewhere in the junkbox, complete with the little roller cam assembly.  I could remove and modify one of the detent cams to make it run the microswitch.  Not sure if I would need to remove the other detent cam.  It might help make sure the switch was properly indexed and seated each step, since the only satisfactory 90° angle drive I have has a small amount of slop due to backlash.

Instead of the added complication of a feedback circuit to indicate position, I might just use the  receiver to indicate if an antenna is connected, and count steps to  determine which tuner is selected, since I will be using only 3 of the 10 positions on the dipole, and if another wafer section is Rube Goldberg'ed into the assembly for the vertical, I'll use only 2 of 10 positions of that one.

First, I'm going to have to completely rebuild the dog-house.  The existing one is falling apart, with the original plywood almost completely de-laminated, plus wood rot and termite damage. I don't think it will make it through another season.  Believe it or not, it was made from an old broadcast radio floor console cabinet dating back to the late 30's or early 40's.  It had a 78 rpm turntable plus an AM/FM  radio that covered the old 40 mHz FM band.  I covered the top with flashing and the sides with asphalt shingles to protect it from the rain, and nailed on a sheet of plywood for the back "wall" and made wooden doors for the front.  This was supposed to be a temporary JSment, to last a couple of years until I could build a good one.  It has lasted about 28 years instead.  Besides falling apart, the existing one is too small to accommodate an additional tuner I plan to add. After replacing the shelter I can then think about revising the switching set-up. I'll build the new dog-house with pressure treated and/or synthetic materials.

[KM1H]

It doesn't need to be a cam with a detent it coulld also be a disc with say allen cap screw heads to catch the microswitch. Just allow enough slop in the system so the switch lands in its own detent when the moror stops

Go high tech, just a disc with a hole every 35* and add a few LED's and a photo transistor outputted to the control circuit. Use a motor geared down to some comfortable speed.

I just gave myself a bright idea for switching input networks when using oddball 36* index Centralab JV series switches.

Carl

[k4kyv]

I just gave myself a bright idea for switching input networks when using oddball 36* index Centralab JV series switches.

What exactly are those?  36° is what my switches are indexed, not 35°

[KM1H]

Sorry, my goof, I was referring to the big Radio Switch Corp Model 88 switch. Now Multi Tech Industries. I used to sell loads of those and Model 85's to serious QRO builders

But here is the Centralab info anyway.
The old JV 9900 series Centralab ceramic power switches as used in many, many commercial amps from Alpha, Dentron, Ameritron and almost all others in the 1500W+ category. It uses an oddball 20* index which makes it hard to mate a series phenolic switch to control a relay switched input board.
Currently the Electroswitch E-4 series since 1992

http://www.electro-nc.com/rotaryus/e4.pdf

Carl
KM1H

[w3jn]

I like that!  Don could use one of the existing detent cams on either of the two switch assemblies.  Just mount a microswitch with a roller on it where the spring assisted detent follower currently resides.  You will still need a small added wafer to tell you which position the switches are in using an array of small lights or LEDs in your control panel.  Great idea, John!

Hey, I neglected to notice that Don's switches already had cams    That's an even better idea, using the existing cam!

Don, ya only need one extra wire (and another switch bank, of course) to run the meter position indicator.  You could also just bust the stops off a pot and drive the pot with the same shaft.

[WBear2GCR]

Don,

One way to go is the Zenith TV "clicker tuner" method... basically all you need to do is to remove the detent mechanism (or use a much much lighter spring, or modify the depth of the detent gear...) and add a wafer that has the same degrees of rotation per contact as does the main switch. Then all you need is a simple "up down" motor (DC). The added wafer does the sensing. When you hit the up button the motor turns on, and keeps going until it hits the next contact, then it stops, or if you hold the button, it keeps going until it hits the last one which is wired so that it can then only go down...etc... clever system.

You can rig an indicator with two wires, just add one more wafer and that can be a voltage divider or half of a bridge (same idea) that can read out on a meter or whatever you rig up...

              _-_-bear