Amps for remote operation

Discussion in 'Amateur Radio Amplifiers' started by WU3I, Mar 4, 2018.

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  1. WU3I

    WU3I Ham Member QRZ Page

    Looking for input from remote operation users on the amps you are all using. Want to build a better mousetrap and be able to turn on and off the amp as well as standby to operate via emote operation. I know it would have to be solid state or autotuning. I have4 the Tokyo Hy-Power HL-2.5Kfx but there is nothing I can find online to remote operate it without extensive wiring to external relays.

    Any input would be appreciated. Station will be using a flex series 6000 radio as they are the easiest to remote operate.

    Steve WU3I
  2. W1BR

    W1BR Ham Member QRZ Page

  3. WW1WW

    WW1WW Ham Member QRZ Page

    The Remote Ham Radio guys have gone with the KPA1500
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    If I was going to run a amp remote, I would build a control interface that includes a time out timer. A video camera for the station would be nice too.

    Have Fun.
  5. KB2E

    KB2E XML Subscriber QRZ Page

    A time out timer separate from the rigs TOT and remote kill switch for the entire radio system would be my number 1 considerations. Good video showing the watt and SWR meters, some sort of light that indicates a sudden SWR change and the transmit indicators would be essential as well. I just had my IC7300 stick in transmit while running remote (RF in the shack due to an antenna feed line issue that had deveolped) then a trace on the PA board decided to short and it took out a THP HL-1.5Kfx in the process. The 7300 was repaired under warranty with the remark by the tech, "Yea, we see some of these shorted PA's." I just hope it's a few and not a big SN range. The 7300 board shorted at 35 watts so it would have shorted evenatually regardless. My point is had I seen the SWR rising and the "snowball rolling down the hill" I would have been able to save the amp. As it turns out the amp couldn't save itself BECAUSE the feedline problem likely took out one of the protection relays on the RF detector board (burn hole in case of RL502), a problem known to THP 1.5 users when a sudden antenna problem shows up. It's essential you pay attention to the panel on the amp! The fault can occur, the signal to take the amp offline can be sent but if the relay is toast and does not respond the amp will follow soon after.
  6. G3YRO

    G3YRO Ham Member QRZ Page

    Personally, I couldn't imagine running a Linear Amplifier at a remote station under ANY circumstances !

    Good Luck . . .

    Roger G3YRO
    KN1M and N8VIL like this.
  7. W1QJ

    W1QJ Ham Member QRZ Page

    Times are a changing Roger!!
  8. AI3V

    AI3V Ham Member QRZ Page

    You want a kw, brick on the key, no tune-up, and remote?

    How about a surplus an/urt23 ?

    A pair of 8877's

  9. SM0AOM

    SM0AOM Ham Member QRZ Page

    I would not recommend the use of any tube-based amplifiers for current remote operations
    unless you have a maintenance crew handy.

    In a previous occupation, I was responsible for operating several 10 and 2o kW servo-tuned Collins
    and Telefunken transmitters for commercial air/ground services operating H24,
    which needed attention perhaps not on a daily basis, but at least weekly.

    Replacing them with Rockwell-Collins solid-state equipment made it possible to run the operations
    "lights-out" with scheduled visits about every 3 to 4 weeks.

    For example, both the Harris RF-110 (which uses 8122s and 4CX1500Bs)
    and the Collins HF-8020 are quite dependent on healthy emission
    in both the driver and final tubes to work "as advertised".

    Having limited experience with amateur-grade solid-state amplifiers, it is somewhat difficult to
    provide detailed advice, but a general approach would be:

    • Use a sufficiently de-rated amplifier to increase reliability
    • Have extensive protection devices; SWR, temperature and power mains quality, over/under voltage
    • Use adequate precautions against RF feedback
    • Employ a hardware keying time-out switch or "watch-dog"
    • Use a "main switch" for power to the whole transceiver/amplifier setup, preferably accessible via some other path than the Internet
    • Use adequate transient and over-voltage protection for both the antenna feedline and incoming power/control lines
    • As others have said, a web-camera would be an asset
    As it stands. the HL-2.5Kfx is not intended for remote operation, as the "AC power" and "Stby/Oper" switches cannot be accessed remotely by any existing internal or external interfaces.

    The way to do this would be either to make some sequencer circuit that would operate both switches using solid-state relays or optocouplers each time the "main switch" is activated by remote control, or to use some parallel I/O to create the same functionality.

    If this is not acceptable, it remains to find a suitable amateur-grade amplifier that has full remote control capabilities. One such may be the SPE 2K-FA.

  10. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Hello Steve,

    Owning a IC-7300 setup for remote operation I wanted to punch up my transmit signal a bit with a linear amplifier. Commercially available units where either out of my price range or didn't have the functionality that I wanted.

    Last year I designed and built this little 600 watt solid state amplifier based on the Motorola EB-104 design.

    Amp with wood sides.JPG

    This amplifier was auto power up and shut off initiated from the IC-7300. The 7300 also controls the band selection and puts the amplifier in standby while the auto antenna tuner does its thing.

    The amplifier has over drive protection, high SWR protection along with over temp and over current protection. I have run it remotely about a dozen times with no issues. No web cam but that might be nice.


    K7ART, K1TGX, KA9JLM and 1 other person like this.

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