Callsign
ad: ELADIT-1
Page 2 of 2 FirstFirst 1 2
Results 11 to 15 of 15

Thread: Vacuum Tube Direct Conversion Receiver / QRP transmitter projects

ad: L-HROutlet
ad: l-assoc
ad: l-rl
ad: l-Waters
ad: l-innov
ad: l-WarrenG
ad: l-gcopper
ad: l-tentec
  1. #11

    Default

    Quote Originally Posted by K5UOS View Post
    Homebrew tube receivers are rare.
    You can see quite a few here:

    http://www.qsl.net/k5bcq/HBR/hbr.html

    I know of at least two hollow-state direct-conversion receivers in QST:

    May, 1961 (more than 50 years ago!) W2WBI described a "T.R.F. Receiver" for 80 and 40 with a balanced detector. RF stage, pair of pentagrids, VFO, audio amp. Nice job, but for that many tubes you could have a small band-imaging superhet. Although the term "direct conversion" is not used in the article, it is clearly that kind of receiver.

    July, 1973, shows "The 80 Meter Pebble Pulverizer" by W1CER and W1NPG. A complete QRP CW transceiver for 80 using tubes. 6GX6 is the detector.

    73 de Jim, N2EY

  2. #12
    Join Date
    Jul 2003
    Location
    Located 5 miles north of downtown OKC in Edmond, OK.
    Posts
    1,141

    Default

    Quote Originally Posted by N2EY View Post
    You can see quite a few here:

    http://www.qsl.net/k5bcq/HBR/hbr.html

    I know of at least two hollow-state direct-conversion receivers in QST:

    May, 1961 (more than 50 years ago!) W2WBI described a "T.R.F. Receiver" for 80 and 40 with a balanced detector. RF stage, pair of pentagrids, VFO, audio amp. Nice job, but for that many tubes you could have a small band-imaging superhet. Although the term "direct conversion" is not used in the article, it is clearly that kind of receiver.

    July, 1973, shows "The 80 Meter Pebble Pulverizer" by W1CER and W1NPG. A complete QRP CW transceiver for 80 using tubes. 6GX6 is the detector.

    73 de Jim, N2EY
    Hi Jim,

    I subscribe to the HBR site and the email reflector, too. It is a fine site for anyone interested in researching tube receiver design. Kee's has most of the HBR circuits available for download.
    I also remember your tuning mechanism made with a bowl.

    That said, I would not build a tube receiver based on the HBR series for obvious reasons. It is not a very good performer above 40 and 80M.
    But I have used circuits like the audio stages and IF stages from the HBR. The HBR14 is a good candidate for a DDS (like Pat, WA6MHZ is designing) but the RX's still need improvement in selectivity.

    I knew there were other DC tube receivers. There are some others on the web and I know we have discussed ideas about them on the glowbugs site.
    But Galen, WB0RIO, has a unique design, all his own. It is pretty cool! There are not many folks scratch building tube receivers (or any type receiver) and a unique design is nice to see.

    There were reasons the tube DC receiver didn't catch on. You mention one above. For all the work you could build a really great entry level superhet. There are lots of other caveats.
    Since effectively all the gain is at audio (often > 100dB) the difficulty increases in tubes over solid state.

    I like pointing out your station: It is unique, too. Tubes are fun.

    73, K5UOS

    n2ey.jpg

  3. #13

    Default

    My (older) brother and i built the pebble pulverizer ( thats actually a stretch, he did most of it, i just made a mess) i do remember that the thing was really prone to microphonics (an understatment) and common mode overload, wls came in like gangbusters everywhere and all of the time. And the selectivity was pretty bad. The regen he built didn't suffer from any of that stuff.... at least not as badly anyway.

    40 years later i've forgotten all of that and think that a tube DC rx is a good idea.

    73 m/4

  4. #14
    Join Date
    Mar 2003
    Location
    3763 Lyle Avenue, North Pole, AK 99705
    Posts
    22,891

    Default

    Quote Originally Posted by WB0RIO View Post
    You all might be interested in this pair of vacuum tube hacks I put together this winter:
    http://www.solorb.com/elect/hamcirc/...nv1/index.html The House Finch Direct Conversion Tube Receiver
    and
    http://www.solorb.com/elect/hamcirc/...ns1/index.html The Little Chickadee 6U8A QRP Transmitter.

    Both projects are built around common 6U8A tubes, the receiver also has a 6BA6 RF amp and a 6C4 audio preamp.
    Before building the receiver, I searched the net for tube-based direct conversion receivers and did not find any
    previous work.

    73s
    Attachment 89007 Attachment 89008
    That's really cool. I LOVE the cabinets!

    Eric
    "The more you know, the less you don't know."

  5. #15
    Join Date
    Feb 2002
    Location
    Right here
    Posts
    13,002

    Default

    I second Erics statement Galen, very clever use of the electrical boxes as chassis. I'm curious, why a DC receiver and not a regen?
    I'm sorry you don't have the experience or understanding to realize that others possess a skill set that you seem to dismiss as fantastical.

Page 2 of 2 FirstFirst 1 2

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •