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what is the best HF rig ever made??

Discussion in 'General Technical Questions and Answers' started by M3WFO, Dec 5, 2009.

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  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Yeah, it's actually both. The S3A has the 14 extra bandswitch positions for the crystal deck and is otherwise the same as the original S3. The S3C has the same extra positions and is otherwise the same as the later model S3B.

    Even if you had the 140 crystals, you'd have to change them ten times in the deck to get "full general coverage" of HF.

    You could add a synthesizer to a lot of receivers to make them general coverage!;)
  2. K9STH

    K9STH Ham Member QRZ Page

    Several decades ago there was a construction article in 73 Magazine about building a synthesizer for the Collins 75S- series receivers. That definitely made it "general coverage", at least from 3.4 MHz to 30.0 MHz.

    I do make additional crystal boards for the S-Line that gives additional crystal positions. But, being able to handle the complete CP-1 (Collins did have an accessory "pack" that had all the crystals to make the S-Line "general coverage") would be a construction "night mare"! The kits that I make require lifting the top cover of the unit to switch the crystals, but, they require no modifications to the unit. I have one in my 75S-3A that gives me the entire 10 meter band as well as 60 meters, 17 meters, and 12 meters. The 30 meter band can be covered by changing the WWV crystal from 14.8 MHz/15.0 MHz to one that gives 10.0 MHz/10.2 MHz.

    The 75S-2 receiver also has the additional crystal board and otherwise is the same as the 75S-1. Both the 75S-2 and 75S-3A are pretty scarce with only about 500 of each having been manufactured. There are literally thousands of the 75S-3C receivers around. I don't have a 75S-2 but I do have a 75S-3A.

    The Eldico R-104 has the additional crystal board and was the "second source" for the U.S. military for the Collins 75S-2. There were about 1500 R-104 receivers built.

    Glen, K9STH
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I missed out on that one, but I have the matching microphone (D-104).:p
  4. W8ZNX

    W8ZNX Ham Member QRZ Page

    you are grabing at straws

    the 75S-3 can not do General Coverage
    even with all the rocks or synthesizer

    check the specs
    freq coverage
    3.4 to 5 MHz and 6.5 to 30 MHz

    the preselector will not go below 3.4 MHz

    no AM BCB, no 160 meter band,
    no 120 meter bcb, no 90 meter bcb,
    and there is that gap
    between 5 MHz and 6.5 MHz

    only way to realy get General Coverage on a 75S-3
    would be to use converters

    then it is still not a General Coverage Receiver
    Last edited: Jan 14, 2010
  5. K9STH

    K9STH Ham Member QRZ Page


    Obviously, you missed Service Information Letter 2-75 (copy available at )

    This eliminates the need for the 5.0 MHz to 6.5 MHz "gap". Also, the same Information Letter extends the lower range to at least 3.3 MHz.

    There are certain very small segments in the 5.0 MHz to 6.5 MHz range that Collins does not recommend transmitting in but the receivers can cover the entire range from 3.3 MHz to 30.0 MHz.

    The 60 meter band does not have any of the "caution" frequencies and I definitely can use my 32S-3 / 75S-3A on the 60 meter band. Now I have added an AADE digital readout to my 75S-3A to insure that my frequency is within 10 Hz which is as close as any "modern" unit can reasonably hold.

    There are other "general coverage" receivers that have "gaps" because of i.f. frequency problems. For example, the Hallicrafters SX-100 does not cover 1.55 MHz to 1.72 MHz because of the i.f. at 1.610 MHz.

    Glen, K9STH
    Technical Advisor Collins Collectors' Association
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I like the TR-7 for this reason (and others).

    It really is continuous coverage from 1.8 through 29.999 MHz, both TX and RX, with no "keep out" zones. Its RX first IF is 45 MHz.

    A really versatile rig for its age (32 years now), but of course with "general coverage" TX ability, the operator needs to watch what he's doing!;)
  7. WA1IIE

    WA1IIE Ham Member QRZ Page

    My favorites

    RCVR: Collins 75A-3/4
    TX: Collins KW-1
    just my biased opinion.
    Lots of "better" gear but these are fun together.
    Yaesu FT101 series were great hybrid XCVRs in their day.
    Johnson Ranger II was a fine low pwr TX.
    Remember Clegg VHF gear? Top notch in their day too.
    What was that fancy top-end National RCVR? HRO-?
    Hammarlund Super-Pro Rx!
    Collins R-390A, of course!

    Wish I could afford to try out the new Yaesu/Kenwood/Icom top end rigs.
    My National NC-303 picks up weak cw stations as well as my IC-735
  8. W1GUH

    W1GUH Ham Member QRZ Page


    Saw one at a hamfest last summer, but couldn't afford to even ask what he wanted. On second though, 7 months later, I wish I had. There's always the chance (as improbable as it seems) that I COULD have affrded it. Guess living in a QTH where HF receivers are useless takes away some of the motivation.

    I've also been interested in the NC-400.
  9. W1GUH

    W1GUH Ham Member QRZ Page

    Re: the number of crystals for general coverage 75-S3x's....

    Sure, it take a LOT of crystals for full coverage, but in most applications that's major overkill. Not all the HF frequencies have interesting stuff in them, and the reasonable approach would be to just get those crystals that let you hear what you want.
  10. 2E0RPS

    2E0RPS Ham Member QRZ Page

    You will never get precise answer.

    it all depends on your preferences and modes. I've used few Rigs (old and new) and i came down to an FT920 and IC 746 (my current set up) and they work very well in different ways.

    hope this will help?
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