Station control.....

Discussion in 'Amplitude Modulation' started by N2DTS, Jul 2, 2020.

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  1. N2DTS

    N2DTS Ham Member QRZ Page

    I think I need to re do the station control.


    I built that 35 years ago, it has a big open ceramic base relay for T/R switching, a bunch of small relays for muting, switches for antenna selection, transmitter selection, receiver selection, what AC from which transmitter keys things.

    While the switches are good for the power, some have poor isolation and RF is floating around in all the AC and muting stuff.
    Its also designed wrong as the PTT is by each transmitter, not one switch on the microphone.

    I want one 12 vdc PTT and relay that will key all the transmitters (not at once) separate from the RF, LOTS of keying and muting outputs in a labeled rational way .

    T?R relay in a seperate box, with another relay that shorts the RX output to ground, and all switches with better isolation and less SWR impact at higher frequencies.

    The current setup is very handy to pick one of 4 antenna's, one of 4 high power transmitters, one of 7 receivers, and the ability to have a tuna in only the TX side if I want, along with a watt meter/mod monitor output, all in one handy box at the operating position.

    The new setup will not be as slick I think, but might work better.
    It means tearing everything apart and re doing it....

    I have 3 big transmitters, a 32V3, a flex 5000, an Icom 756 pro2 that will be the exciter for two big transmitters and the K7dyy rig coming, along with various small sdr rigs, the Heathkit MT-1, the Neuvo 75 and other stuff....

    I bought a couple of Alpha Delta 4 position coax switches and an old B+W 6 position switch which is just a regular switch in a box with coax connections on it, not good for a lot of power and no isolation.
    K0UO likes this.
  2. KA0HCP

    KA0HCP XML Subscriber QRZ Page

  3. W9BHI

    W9BHI Ham Member QRZ Page

    Obviously a sequencer is not what you are looking for.
    You are looking to build a better station management system.
    Being sort of lazy, I made up a switching matrix that configures all of the interconnections between my transmitters, audio gear, amplifiers, tuners and antennas just by which one is powered up.
    There are circuits involved that make sure only one transmitter can be keyed and connected to an amplifier or selected antenna system at one time.
    I also made a nice vacuum relay box to put the K7DYY in and out of the antenna line after my amplifier that was controlled by the switched 12 volt output on the DYY rig itself.
    All the rest of my antenna switching is done by 12v vacuum relays.
    You can design a slick setup if you just sit down with a paper and pencil and draw it all out.
    Don W9BHI
  4. N2DTS

    N2DTS Ham Member QRZ Page

    True, I am not looking for a sequencer, just the ability to select what equipment will be in use at once.
    There are many ways to do it, but I have a large mix of different things, old, new, solid state, homebrew, audio paths, mod monitor audio switching, temp hookups of standalone radios, exciters, etc.
    What I have now has worked well for 40 years, but ended up being a hodge/podge of things mostly crammed into one box.
    The swr through all the stuff changes at higher frequencies, its not easy to add something, and the muting/keying should not have been mixed in with the rf switching.

    The first step is to put the T/R relay in its own box...
  5. KE0ZU

    KE0ZU Ham Member QRZ Page

    My system is pretty simple, and definitely old school, in that exciters, amps RF in/out, and antenna are all selected on a jack field, with jumper cables. An old EFJ electronic T/R switch is used and it's Rx output is run through a diode clamp, attenuator, mini-circuits amp and 1:8 splitter to all receivers.

    Receivers are muted with a common Mute line (12VDC=Tx).

    All Rx audio is transformer coupled and switched through the audio select panel to the speaker amp.

    Transmit Mic audio is run through a separate speech amp, and rotary switched, along with the KEY, to the transmitter of choice.

    I have fairly modern radios and shelves and shelves of boat anchors, and my original goal was to make any transmitter, receiver, or transceiver a simple matter of "plug and play". Over the past 6 or 7 decades there have been many control schemes come and go, so adaptability was paramount.

    I feel I have been able to achieve success, in that I can mix and match any transmitter, amplifier, and receiver with complete success.

    Since I use an EFJ electronic T/R switch, all the linear amplifiers have had their internal antenna switching bypassed and carrier operated relays installed to operate the remaining changeover circuitry.

    Don't know if any of this is of any value to you, but its been working well here, for several years now.
    Last edited: Jul 3, 2020
  6. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    So it appears, that you not only need a Master Station controller but a sequencer as well.

    I can't help you with the Master controller but I do have a sequencer that can key relays in a timed sequence.


    Attached Files:

  7. N2DTS

    N2DTS Ham Member QRZ Page

    I have never bothered with any sequencing till now as I have only run 600 watts carrier and big components .
    These days the max power is about 400 watts.
    I have just keyed everything at once, and unkey everything at once.
    For some reason, that has never been a problem.

    Great setup Mike (KE0ZU) that looks very sharp and well thought out!
    I have loads of patch panels at work, a DS-3 patch panel is even easier then BNC patch panel but it would not work on the TX side
    at high power levels.
    I like the switch setup I have but its not really RF friendly.
    I may stick with the rf stuff as is and move the PTT and muting stuff into a better setup.
    By the way, what do you think of the Kenwood twins (on the smugmug site), I hear good things about them....?

    The Alpha Delta switches seem fine but they do not lend themselves to rack mount.

    My K7DYY rig is due to arrive today (maybe) and I will just shove it into position 4 in place of the 32V3 and see what happens.

    Its going to be a big job to re do all the control stuff!
    Last edited: Jul 3, 2020
  8. K5UJ

    K5UJ Ham Member QRZ Page

    I only have one switch for transmit / receive and it switches a sequencer that times the flip over of everything using 24 v. DC to relays. Every rig, VFO, receiver, rx antenna preamp, tx antenna feedline, and audio amp has a relay. Lots of zip cord going everywhere with diodes across each coil and in some cases bypass caps and chokes at the relay coils. I advise going higher than 12 v. dc. There may be too much Vd on long runs of wire to relays. But if you have a hundred 12 v. DC relays, so be it. Don't go with 120 v. AC. You want to use DC for your switching.

    I don't know what is meant by "key all transmitters separate from the RF." A transmitter IS RF.

    You don't need a second relay to short RX output to ground. You can do that with the same T/R relay if you have enough poles on the relay. Don K4KYV came up with a nice sequencer design that was in the Nov. 2005 issue of ER. Uses relays, diodes, resistors and one cap. Take a look at it. Simple, reliable and it works. or you can go with some fancy thing using a lot of VLSI chips & surface mount stuff.

    I'd use those Alpha Delta switches for receive line. Look for Bird Coaxwitch or homebrew your own for tx AM. However if they work for you then okay. Don BHI has a good idea I have wanted to do: build up a patch panel for feedlines. Way more reliable than a coax switch. Lots of contact surface area....way more versatile than a 3 or 4 pos. switch.

    Have you verified you have no hot switching? If you see no arcing, then FB. I like a sequencer to give relays conducting tx RF time to settle and open only after the rig is off air.
  9. N2DTS

    N2DTS Ham Member QRZ Page

    Well, all the equipment to be switched or muted is close, 10 feet max run.
    As it is, the ac coming from transmitters to power the T/R contactor is in with the RF, its all in that one box (mostly), antenna selection switch, transmitter selection switch, receiver selection switch, all the muting relays.
    I want to move the muting relays out of the RF box.
    I also do not want each transmitter to put out 120 volts to the T/R relay but want to key that with the ptt circuit.
    Each transmitter has a ptt circuit in it, mostly 12 volts that wants a contact closure.
    The 32v ptt is bias voltage I think, but no big deal.
  10. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    Recommend you draw out a system diagram such that control sources and voltages are somewhat isolated from any RF connectors, and then order needed parts.

    I have seen your work; you can do it!:)


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