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Does Flex hardware tally when SSDR has connected?

Lu Romero
Lu Romero Member ✭✭

Hi all:

Im integrating our second remote Flex transceiver at the Tampa ARC. This one is a 6500. In our 6400 system, we have the rig connected to essentially monobanders through an external antenna switch controlled by Green Heron Everyware. Users there manually switch antennas and when they are finished, they ground all antennas via the antenna switch, disconnecting them from the radio.

On this second transceiver, the antenna will be a tribander and a OCF dipole. Since the radio has two antenna inputs, we dont need an antenna switch. However, this means that when the radio is not being used, the antennas stay actively connected to the radio.

Ive purchased a Paradan "automatic" Dual Antenna Disconnector (Dual Antenna Disconnector | Paradan Radio ) to disconnect the antennas from the radio when it is not in use.

Best practice is to leave the radio powered up with 12vdc and not physically "turned off". When a user is finished using the rig, he just closes SSDR on his PC and leaves the rig available for the next user.

The Paradan device can sense when 12vdc is applied to its connector and automatically connect the antennas. When 12vdc is removed, the device disconnects the antennas automatically with no user input needed. This is what I'm looking for! However, there is one problem: We never turn off the radio's 12vdc power and we never "remotely" press the front panel power button on the radio with the rear panel "soft power" switch. This means that the Paradan device would not be able to do its job.

Is there a hardware signal from the transceiver that I can attach a buffered relay to that turns on when SSDR connects and turns off when SSDR disconnects? Per the hardware manual, there is a 5vdc signal on a pin on the AUX connector. The manual does not elaborate when this voltage is present. This signal would then control the Paradan device to automatically connect and disconnect and ground both antennas from the rig when it is not in use. This functionality is important to us as we are located in the Lightning Capital of the USA, Central Florida.

I am not interested in a Node Red flow or other external additional interface devices... We want to keep this simple and automatic. All I need is either a dry contact to ground or a voltage to present itself in a hardware connector on the back panel of the radio when SSDR connects and go away when SSDR disconnects from the RF Deck.

Does this rig have that capability? I would test this, but the rig is not where I can easily access it at the moment to poke around with a voltmeter on. Im assuming the factory people would be able to answer this question.

Important Note: We DO NOT turn off the rig or remove DC power from it when we are not using it... This seems to be the best practice and has given us great stability. We only connect and disconnect SSDR to use the rig.

Thanks in advance for any input on how to integrate this solution.

Lu Romero - W4LT - Tampa ARC

Best Answer

  • KD0RC
    KD0RC Member, Super Elmer Moderator
    Answer ✓

    Hi Lu,

    Sounds good. Yes, I am good on QRZ. I have a Teensy arriving this week to do the development on. I already have most of the code done as part of another project, so it shouldn't take long to port that over and customize it for your needs.

    The schematic will be very simple and easy to build. I will send you a complete BOM once I get everything done.


  • Alan
    Alan Member ✭✭✭✭


    You do not mention if you shut down the Flex Radio using the remote on/off.

    Most use a relay that is operated by some remote means, to operate the remote on/off Flex connection.

    If so, use this same relay (DPST), to operate the antenna dis-connect.

    So...if the radio is "off", but radio power is still applied, the antenna is disconnected.

    Alan. WA9WUD

  • Lu Romero
    Lu Romero Member ✭✭

    Hi Alan:

    Read my "Important Note" in the message again. We have the capability of turning this feature on and off via a web enabled relay system (DCI Ethernet Power Controller), but we normally just have users simply close SSDR on their PC's when they are done using the rig. We have found leaving the radio 12V on and simply disconnecting by closing SSDR is both simpler for our users and adds stability to the whole system.

    All I need is a dry contact to ground or a voltage on any pin in the back panel of a 6500 that either turns on or turns off when SSDR connects to the radio. High or low logic is fine with me, even a voltage will work. I would then connect a buffered relay board to this signal and manage the logic state so that I feed 12v from an independent supply to the Paradan device when SSDR is connected and remove 12v from the power supply to the Paradan box when the radio hardware senses that SSDR has disconnected. This will then connect the antennas when a user logs in to the rig and disconnect and ground the antennas when a user disconnects from the radio WITHOUT USER INTERVENTION OR ACTION.

    I would prefer to keep this as simple and as automatic as possible. Our remote system users have enough of a challenge using SSDR/SmartLink and a web based remote rotor controller as it is without adding yet another device to control independent of the radio. This is supposed to be our "simple to use" radio... The other one, with multiple towers, monobander antennas on tall towers and multiple rotors is the "hard one" they graduate to from this one. It manually grounds all antenna inputs through the antenna switch and GHE software.


  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Hi Lu, That functionality does not exist directly. An external device could be built to do exactly what you want.

    Since the radio knows and can report on any GUI clients (SmartSdr, Maestro, etc) logged in, a LAN connected external device could be programmed to detect this and put out a signal to connect or disconnect the antenna.

    The way I am thinking of this would require no action from the users. It could be done pretty easily with a Teensy board (Arduino work-alike) or a Raspberry Pi. The Teensy would be the cheaper way to go.

    I would be willing to put one together for you if you like. I can either give you the schematic and software, or build it and get reimbursed for the parts and shipping.

  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator

    A USB to BIT cable to back of radio can work. You can define a frequency range for one bit from lowest operating frequency to highest. Use that to trigger a relay for antenna disconnect. Then when a client is connected and on a valid band it would engage the relay to drive the antenna disconnect.

    Probably easiest solution.

    There are other solutions (Arduino, Node Red, etc)

    Dave wo2x

  • Lu Romero
    Lu Romero Member ✭✭

    Sounds plausible.

    So: Define a bit range from 1.8 to 54MHz. The bit cable is only active when SSDR is connected, correct?

    So what you are saying is to tell the BIT cable that all frequencies across this range are active. Short all bit cables together, and separate the ground cable. Place my relay buffer across those two conductors. When SSDR CLient logs on, any active bit will go high against ground. I set my relay buffer active high. This will then turn on the relay which will turn on the Paradan device.

    when the user logs off of SSDR, the bit cables will all go low, turning off the relay buffer and de energizing the Paradan relays shorting the antennas to ground.

    will I have to define the bits into every client or is this a global hardware setting in the RF deck?

    lu w4lt

  • Lu Romero
    Lu Romero Member ✭✭

    KD0RC, you propose to build a device that sits on the local to the radio LAN listening to the hardware via API. I assume the API then has a function that announces client connection status. Your device listens for that API setting. When it’s true, it closes dry contact connection on the Arduino. Then, I connect my relay buffer to this contact. Active low logic then closes my relay to command the Paradan to close its relays. When the client disconnects, the API reports this. The Arduino is watching the API and sees the client has disconnected, it then opens the dry contact opening the relay and de energizing the Paradan shorting the antennas to ground, correct?

    lu w4lt.

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Hi Lu, Correct!

  • I run SSDR on a dedicated monitor. When SSDR is closed, the monitor goes dark.

    Use a photocell duct tapped to the monitor's screen to drive a transistor which provides the needed

    polarity to activate the Paradan.

    No brains required😄

    Steve N4LQ

  • Lu Romero
    Lu Romero Member ✭✭

    Tough to do when the radio and the Paradan is 8 miles from where I’m sitting using SSDR AND 14 different people use the radio. 😆

    lu W4LT

  • Guess I'm lost then.

  • Lu Romero
    Lu Romero Member ✭✭

    KD0RC, we have discussed this issue and we feel that your idea is the way to go forward.

    Can I:

    • Contact you directly (my email is good in QRZ) and
    • Get a parts list so we can get the hardware together

    I will write up a document that outlines the needs and functionality required so there are no surprises (scope creep). Ill send it to you and we can then discuss any questions or needs between us.


  • KD0RC
    KD0RC Member, Super Elmer Moderator

    For those following along, the Flex Antenna Disconnector is complete. Not surprisingly, I used a Teensy 4.1 board with the built-in Ethernet and stole copious amounts of code from the TeensyMaestro project.

    The device has two primary functions:

    1. Antenna disconnect using a Paradan antenna disconnector.
      1. When a GUI client (SmartSDR, Maestro, etc) connects to the radio, a pin on the Teensy is set which tells the disconnector switch to close, connecting the antennas to the rig.
      2. When there are no more connected stations, the switch opens, providing some measure of protection from nearby lightning strikes.
      3. The operators (mostly remote) don't have to know anything about the switch (or remember to use it). They may not even know of its existence. When they connect via SmartLink, the switch engages and when they disconnect, the switch disconnects the antenna - all fully automatically.
    2. Bandpass filter selection based on bands in use.
      1. One panadapter open on a ham band sets the corresponding pin on the Teensy that selects the appropriate bandpass filter (kind of like a bit cable).
      2. If another panadapter is opened on a different band, all filters are disengaged (like WIDE mode in SmartSDR).
      3. If a panadapter is open on a non-ham segment of the spectrum, all filters are disengaged.

    If anyone is interested in the code, schematic or more detailed write-up, here is a link to the GitHub repository for the project:

    Like the TeensyMaestro, I use an SD Card based Config file to set various options (serial number to connect to, pin active polarity, etc.). The goal is to make it flexible enough for the Tampa Amateur Radio Club's needs so that they don't need to re-program the Teensy; just change the Config file as needed.

    It was a fun project, and I hope the units work well for TARC.

  • Lu Romero
    Lu Romero Member ✭✭

    Thanks Len!

    Will start working on this as soon as I get the parts. Will download the info in the next few days.

    Lu W4LT

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Sounds good Lu. Not sure that I mentioned that you will need one device for each Flex that you connect to.

    Once you get the Teensy boards, load them with the firmware first to validate that they are working. I set the on-board LED to light when a GUI client (SmartSDR or Maestro) connects. That way you can verify operation before wiring up the transistors and connecting to the Paradan or the filters.

    It will also let you test to be sure that the Config file is set up correctly for each radio.

    Don't hesitate to call if you have any questions.

  • Lu Romero
    Lu Romero Member ✭✭

    Thank you again, Len!

    Yes, parts are now on order should be here by the weekend. Im making 3: One for my personal radio as the Lab system, the other two for production. This way, if any changes are made, we can debug and make sure they work before propagating them into the actual club environment.

    And, I'll learn a little about Arduino in the process!

    Ill let you know how things turn out.


    Lu Romero W4LT

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Excellent! It will be fun to see this in actual operation.

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