Elecraft K4

Discussion in 'Ham Radio Discussions' started by W6RZ, May 16, 2019.

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  1. KM1H

    KM1H Ham Member QRZ Page

    Gee whiz, then I guess my late 1920's style HB 160-40 rig starting with a 27 oscillator and ending in a 210 (Im still working on the 860 final) along with a modified Radiola 60 superhet using a period correct HB external converter qualifies as a fun radio or would it be the prewar Meissner Signal Shifter and National FB-XA, or the HQ-129X and Viking I which recreates what I had in 1956 when I got the General? I also have several other examples of vintage "fun" but I dont keep harping on them.

    Vintage SSB with decent IMD since this is what this thread is about? OK so then there is the 1959 Central Electronics 100V Ive had since 1965 and a Gonset GSB-10o; both are phasing rigs with very nice audio.
    Anybody else have ACTUAL similar vintage SSB rigs to comment about and not about some old magazine ad?? Speak up.

    Maybe I should modify my WW2 ATC (USN ART-13) as an SSB amp, the 813 is certainly IMD clean enough:eek: and the Collins PTO is very stable.

    NL7W likes this.
  2. KP4SX

    KP4SX Premium Subscriber QRZ Page

    My old HX-50A sounded great. Sideband filter was 3.1 kc wide according to the freqs stamped on the assembly :) I don't know how good/bad the IMD was. TV sweep tubes. :)
    I suspect the spec snobs would chase you off the band these days.
    KM1H and WN1MB like this.
  3. KM1H

    KM1H Ham Member QRZ Page

    Most sweep tubes were pretty good when run properly and l0w -30's REAL IMD3 was common. When run hard they were in the mid teens....but so were 4CX250B's!
  4. NL7W

    NL7W Premium Subscriber QRZ Page

    I just can't help myself...
    I hear many CB linears are "bi."
    Sorry. :cool:
    KA4DPO likes this.
  5. N2EY

    N2EY Premium Subscriber QRZ Page

    Actually, the thread is about the Elecraft K4.
    N2SR and KJ4VTH like this.
  6. KJ4VTH

    KJ4VTH Ham Member QRZ Page

    And how much better it is than some old tubes. ;)
    AB6RF likes this.
  7. KM1H

    KM1H Ham Member QRZ Page

    What those without sufficient knowledge (and there are several posters on here that qualify but keep showing their ignorance of the subject) do not realize is that in the REAL WORLD the IMD products are cumulative as well as additive with other signals which produces new IMD frequencies. With enough activity this can/will raise the band noise floor with what is termed WHITE NOISE. Just listen or watch above or below the SSB area during a contest. The higher HF bands plus VHF and above are especially prone since natural band noise is lower.

    Having been involved at the engineering level of CATV line amps in the early 80's I soon learned to respect the industry IMD requirements for an ultra linear amp that had to handle up to 80 TV channels all of the same input level from the head end. This is a dBmV measurement into a 75 Ohm system while most power is in dBm. The conversion math is very simple and well referenced.
    The 2N5109 was a CATV line amp development for the industry in the 70's and has been one of my favorites ever since especially for HB VHF/UHF transverters and preamps/postamps.
    The industry has evolved and broadband SS modules now handle the amplification well into the UHF range.

    Here is a very informative read from a well respected industry publication:

    This paragraph in particular is worth reading and understanding! Since the author worked for MACOM I have a strong suspicion he is referring to good old Motorola which would explain a lot about published results using some of their products:

    Was this deliberately misleading by MOTO or ????

    N0TZU likes this.
  8. W3KHG

    W3KHG Ham Member QRZ Page

    Elecraft calls them Razor Blades. You buy the Razor cheap but they hit you up on the Razor Blades.
    KA4DPO and WN1MB like this.
  9. N3AWS

    N3AWS Ham Member QRZ Page

    Yes! You are!

  10. N2EY

    N2EY Premium Subscriber QRZ Page

    Just to be clear - this effect happens in the receiver. The white noise "isn't really there"; some receivers will "hear" more of it than others.

    "Often, what makes one receiver better than another is what you DON'T hear".
    N0TZU, N2SR and N3AWS like this.
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