Receiving Equipment

Discussion in 'The Low Bands - 630/2200 Meters - VLF' started by K9STH, Nov 10, 2017.

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  1. N9LCD

    N9LCD Ham Member QRZ Page

    I had a WRR-3 back in the 80's when I had a DC to Daylight -- 6 KHz to 1,000 MHz monitoring shack.

    If you can find them today, the rig goes down to 6 KHz and up to 600 KHz. For VLF/LF, it's a reasonably "modern" superhet with counter-type readout and miniature tubes.


    The WRR-3A is a completely enclosed set. To service the electronics, you remove the chassis from the cabinet and, unless you have the extender cord, you have to remove the feed-through blister from the back of the cabinet to connect power and your signal source.

    The tuning mechanism for the rig has a mix of plastic and metal gears which mesh. The problem: the meta;l gears chew-up the plastic ones and you have to replace the entire readout and gearbox. NOT a stellar piece of American engineering
  2. NO3M

    NO3M Ham Member QRZ Page

    The lower two signals are JT-9. The other signals near your marker are WSPR. (Most audio-generated digital modes use same dial frequency of 474.2 USB)

    Most of us run CW at or below 474.5

  3. K8JD

    K8JD Ham Member QRZ Page

    I have not listened to 630M in a few days, but will go back tonight.
    Some T-storms down south have been tearing up 160 and 80m the last few nights.
  4. N8AFT

    N8AFT Subscriber QRZ Page

    Hi John, I had the chance to use the CALF liniter Saturday night with the T-storm noise on 80. I had the TS830 without the filter and the R7 with the CALF. The difference was simply amazing! What was a sharp loud Crash on the TS was only a Puff using this CALF from KC9ON. Easy to copy Morse during a storm with a moderate S7 signal to work with. Greatest audio add-on accessory I have ever spent money for.
    I couldn't do with out one now. I know limiters are easy to build but there's something better about this circuit.
    Sorry to advertise but I figured guys would be interested in my results.

    Learn Morse
    Do CW
    Last edited: Mar 19, 2018
    KB4QAA likes this.
  5. K8JD

    K8JD Ham Member QRZ Page

    The narrow, variable, audio filter in my FT990, along with the 250Hz IF filter get most signals thru the crashes.
  6. K6AEA

    K6AEA Ham Member QRZ Page

    Seems that I need to dust off the trusty old HP-3586B.
    My apartment location will be my greatest handicap.
  7. K5UJ

    K5UJ Ham Member QRZ Page

  8. N8AFT

    N8AFT Subscriber QRZ Page

    Latest investment here is a Cubic CDR-3250 VLF - HF retired military receiver. 10kHz to 30mHz.
    Last of the stand alone mil spec SDR-DSP knob radios, or so claimed to be.
  9. N2RDQ

    N2RDQ Ham Member QRZ Page

    Cubic CDR-3250 - I really like mine.
    I understand the same thing, that it was the last us government contacted stand-alone receiver.
    I did a bit of research on it and its likely true ... though the information isn't all in one place... I do know the CDR-3250 was a hybrid and was / is used both standalone and as part of their c4isr (Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance) systems.
    The government switched to receivers plugged into VXI bus's for their C4ISR needs and cubic created the same receiver in a VXI form factor after that called the VXI-3250A that had no display or knobs, (VXI is a bus/chassis and the receivers then plug into a vxi chassis... its basically a blade type chassis, if you ever seen a blade server). those receivers are purely accessed through their c4isr systems. companies like WJ made/make receivers for VXIbus as well.

    the military receiver technology has grown now to where they get the whole chunks of rf spectrum and analyze it all at once. similar to us grabbing relatively small chunks of bandwidth and view them on a waterfall plot and pull out CW signals etc. crazy stuff. it's likely we will see VXI bus military receivers popping up.

    Is the ten tec RX-340 the last man standing for the stand-alone premium receivers still in production?

  10. N8AFT

    N8AFT Subscriber QRZ Page

    Well, since Ten Tec is outta business.....

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