September 2011
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The Nautel AMPFET 1

The Nautel AMPFET series transmitters date from the early 80’s through early 90’s.  They were Nautel’s first attempt at MF Broadcast transmitters and were quite successful.  This particular transmitter was installed in early 1990 at WBEC in Pittsfield, MA:

Nautel AMPFET 1 AM broadcast transmitter

Nautel AMPFET 1 AM broadcast transmitter

I believe Nautel got started making MW transmitters for Marine Radio stations, Aeronautical and Marine radio beacons, and similar equipment. Their early equipment is very rugged and designed for rough/continuous service.  The early solid state broadcast transmitters like the AMPFET were not hot plugable but who cares, they almost never break.  The design is simple, efficient and it sounds good on the air.

Early transmitters were housed in racks that were much shorter.  In later versions, the racks became larger to standardize the transmitter size with comparable units of the day.  Inside this cabinet, there is a lot of empty space.

The design is modular, RF modules and power supplies can be removed from the transmitter for repair, unlike the Harris AM transmitter products of the same or later periods.

There later AM transmitter versions built on the AMPFET experience.

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4 comments to The Nautel AMPFET 1

  • Ed B

    I remember when WICC had a Nautel half rack size Apmfet 1 transmitter. It would only modulate to 95% negative peaks and than flat top you could hear it on the air. I called Nautel they said that’s the way it should run. Also the ALC power control if I remember was very flakey hard to keep it set at the correct power levels for 500 watt and 1Kw. So out the door it went.
    I wonder if the one in the picture at WBEC will do better then 95% negative peaks?

  • Paul Thurst

    Ed, that’s interesting. I have never heard about the -95% peak thing, although I tend to run AM transmitters with not more than -95% anyway to prevent distortion from cheap diode detectors that many AM radios use. Pinching the carrier all the way off on the negative peak causes the diode to become less linear in it’s response, leaving 5-10 percent carrier there helps this. Also, severely pinching off the carrier causes splatter.

    When the WICC Nautel transmitter went out the door, which direction did it head?

  • I haven’t got experience in Nautel AM transmitter, but on their website NX100 series is awesome ! Very efficiency, save space when installation and look cool !
    We owned 2 FM10 from Nautel, they have been working well since 1997 (required tuning PA yearly when service)and 2 V10 for our remote site !

  • Juan Belmonte

    Im the Engineer of Radio La Cruz del Sur fromm La Paz Bolivia .We have a transmiter in AM AMPEFET ND 10 serial ñumber H341 Freq 720KHZ I need a diagram of the power modules to make a good repair.
    Also if you can put me in contact with a person that can quote a AM digital transmiter 10KW and a 2KW FM digital transmiter.That will have to include a trip to CANADA to be trained.

    Thank You very much


    Juan Belmonte

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