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$3.50 Ham Transceiver Kit — Parallax Forums

$3.50 Ham Transceiver Kit

ercoerco Posts: 20,257
in General Discussion
Why not? At that price, it's worth it just for the soldering practice/therapy. I got two for the twins, natch.

http://www.ebay.com/itm/321913864124
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Comments

  • User NameUser Name Posts: 1,451
    Interesting transceiver. In a QSO between two of these boards, it looks like the rx tone heard is just the accidental and incidental difference between the oscillator frequencies of the two boards. Works for me. Guess I'll know more in a week or two. :)
  • ercoerco Posts: 20,257
    User Name wrote: »
    Guess I'll know more in a week or two. :)

    You and me both, Brother! I wonder if a simple wire or whip is sufficient for a few hundred feet.

    Agreed, the rx sidetone is likely whatever the difference is between the two crystals. I didn't bother explaining about CW and sidetone since it's a ham-only frequency and hams know all that stuff. Not that anyone would crack down on these microwatt transmitters. I'm guessing that for the most part, TVI is a thing of the past in this hifi wifi bluetooth hi-def hi-res blackfin quad core digital age.

  • User NameUser Name Posts: 1,451
    erco wrote: »
    User Name wrote: »
    Guess I'll know more in a week or two. :)
    I wonder if a simple wire or whip is sufficient for a few hundred feet.
    Just the sort of thing I aim to determine right off the bat.
    I'm guessing that for the most part, TVI is a thing of the past...
    In fact it is phenomenal how terrestrial DTV has made every channel here picture-perfect. I imagine the only interference from little boards like this would be to other QRP operators in the vicinity of 7.023 MHz.

  • jonesjones Posts: 281
    erco wrote: »
    Not that anyone would crack down on these microwatt transmitters...
    800,000 to 1,200,000 microwatts [From the specs: Output Power: 0.8W(9V power supply) / 1.2W(12V power supply)].
    erco wrote: »
    I wonder if a simple wire or whip is sufficient for a few hundred feet.
    If the piece of wire isn't short and the band conditions are decent, you might get a few hundred MILES, not feet. It's not likely to cause TVI, but be careful about unlicensed operation. Your neighbor won't hear you, but on the 40m CW band, a lot of other people might.

    Eons ago I was naively testing a 40m CW transmitter using a light bulb on my desk as a dummy load. The rig produced a bit more power than these little boards(~20W, IIRC), but my "antenna" was the light bulb and a few feet of zip cord. I was stunned to hear my callsign coming out of the receiver when I got a call from a ham roughly 300 miles away who heard my test. I never used a light bulb for a dummy load again.



  • ercoerco Posts: 20,257
    edited 2016-06-21 21:53
    Nice bulb antenna, jones! What was the SWR? :)
  • jonesjones Posts: 281
    edited 2016-06-22 01:08
    VSWR? Details, details. Don't think I checked, actually. It was just after I got my novice license (47 years ago) and I was obviously pretty clueless. There was no smoke, nothing melted, and I had to be radiating most of what the final was producing or he'd have never heard me, so how bad could it be? :lol:

    Edit: Long ago that was actually a common thing to do if you didn't have the spare cash for a Heath Cantenna. These were tube transmitters with pi-network outputs, and they were surprisingly capable of matching poor loads. Besides, is it really that crazy? I think I used a 100 W bulb. Driving it with 110V RMS, R = V^2/P so in really round figures that's 110 squared over 100 or about 120 ohms when the filament is hot and it's mostly resistive. That's less than 3:1 VSWR. Not good, but not that awful.
  • ercoerco Posts: 20,257
    Ha, I got my novice ticket about 45 years ago. WN4CIK, later changed to WA4CIK. Sure would be funny if I had QSLs with you or somebody else here. Stranger things have happened!
  • localrogerlocalroger Posts: 3,452
    Well Jones if you were lighting the dummy bulb you probably weren't radiating most of the signal, but enough of it to get a solid QRP link. One percent of 20 watts is what a lot of QRP operators use to regularly get 300 miles.
  • Cluso99Cluso99 Posts: 18,069
    I obtained my limited licence (full ticket excluding morse) in November 1970 - VK2ZTZ.
    I finally let my licence lapse about 4 years ago since I hadn't been on air for >20 years.

    Of course now there are the SDR's around I could get interested again. Then again maybe my time is better spent with prop things ;)
  • jonesjones Posts: 281
    edited 2016-06-22 03:23
    I had a high school buddy who was an avid CW operator, and he kept pushing me so I got my novice, general and advanced all in 1969. I've been WB6EOU since then and like Ray I haven't been on the air for over 20 years either except for just a bit of VHF. I'm glad I kept my license current, however, since I'm trying to retire (sort of) and getting the itch to get back on HF. And it was SDR that lit the fire with me, too.
    localroger wrote: »
    Well Jones if you were lighting the dummy bulb you probably weren't radiating most of the signal, but enough of it to get a solid QRP link. One percent of 20 watts is what a lot of QRP operators use to regularly get 300 miles.
    Sure, and how to know how much was heat and how much was RF I have no idea*. Probably mostly heat as you suggest. The whole point was to suggest that it doesn't take much power, nor much of an antenna, to radiate a signal so some care is in order. I should've figured Erco would have a ham license and knew that anyway.

    Maybe we need to figure out some way to combine Props and ham radio.

    *Edit: I suppose some sort of improvised calorimeter might work if anyone were interested enough to try it. I think I'll just avoid light bulbs as antennas :)

  • ercoerco Posts: 20,257
    Ha, the price has increased from $3.48 to $3.66. He who hesitates is lost! Lost a 5% discount anyway.
  • ercoerco Posts: 20,257
    jones wrote: »
    Long ago that was actually a common thing to do if you didn't have the spare cash for a Heath Cantenna. These were tube transmitters with pi-network outputs, and they were surprisingly capable of matching poor loads. Besides, is it really that crazy? I think I used a 100 W bulb.

    Sounds like we may have had the same Heathkit rig, the DX-60B! Still have mine, along with the matching VF-1 for and HR-10B receiver . :) And that light bulb dummy load trick was recommended in the build manual.
  • WhitWhit Posts: 4,191
    erco wrote: »
    Ha, I got my novice ticket about 45 years ago.

    Me thinks you were a HAM long before you got a license.

  • PublisonPublison Posts: 12,366
    LOL
  • jonesjones Posts: 281
    edited 2016-06-22 16:56
    erco wrote: »
    Sounds like we may have had the same Heathkit rig, the DX-60B! Still have mine, along with the matching VF-1 for and HR-10B receiver . :) And that light bulb dummy load trick was recommended in the build manual.
    Nope. I just recall the Cantenna as the most common real dummy load. I was even more cash-strapped at that age and was using a Hallicrafters HT-17 that was old even then.

    If Heathkit recommended the light bulb, I feel vindicated. :)

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    erco,

    We had nearly the same station! DX-60 (borrowed from my uncle) and HR-10 (that I saved up for a year to buy). Inverted-V antenna for 40 and 15 meters. Replaced the DX-60 with a Johnson Viking Ranger when I got my general ticket. Then I sold it all, along with a teleprinter, to my former HS math teacher when my license lapsed.

    -Phil
    AD7YF (former WA9HJK)
  • TorTor Posts: 2,010
    edited 2016-06-22 17:22
    I've noticed this new trend where erco-approved ebay deals go up in price shortly after being "announced" here.. so now, in addition to duly add this stuff to our individual hoardes, we also have to be very quick about it?

    -Tor (who has lost count of the number of erco-initiated items he bought. But today the secretary at work replaced his mailbox with one three times bigger.. there wasn't enough room when several small shipments arrived together, so she decided to fix the problem.)
  • ercoerco Posts: 20,257
    Speed hoarding is a new demonstration sport at the Rio summer Olympics. :)
  • User NameUser Name Posts: 1,451
    User Name wrote: »
    ...it looks like the rx tone heard is just the accidental and incidental difference between the oscillator frequencies of the two boards.

    Hah! I was wrong. As assembly began I realized they were using a 1N4001 as a varactor diode to push the crystal a bit. In minimalist designs things aren't always as they seem. And many times a part serves double duty.

    BTW, in the kits I received the 1K resistors were missing. Not a problem though...

    (What _is_ a problem is what to do with all the R's C's L's and Q's I'll never use up in a lifetime.)

  • ercoerco Posts: 20,257
    You got yours already? I'm jealous! I ordered it first! :(
  • User NameUser Name Posts: 1,451
    Not to worry. A few years ago US Customs created a new department dedicated to processing my orders. :)
  • ercoerco Posts: 20,257
    Mine finally arrived today. Tiny!

    Did you test yours yet? Can I toss my cell phone?
  • ercoerco Posts: 20,257
    Useful info at http://kb2hsh.blogspot.com/2014/12/the-chinese-pixie-2-qrp-transceiver.html. Slightly different board.
  • User NameUser Name Posts: 1,451
    erco wrote: »
    Mine finally arrived today. Tiny!

    Did you test yours yet? Can I toss my cell phone?

    Secret confession: I finished assembling them 6/29 but haven't applied power yet. I've got BIG BIG plans. But better hang on to your cellphone for a few more days, just to be safe.


  • ercoerco Posts: 20,257
    edited 2016-07-03 12:37
    Dang it, now I'm getting the QRP bug and I just learned about FDIM in Ohio last May. Looks like good fun. Anybody been? Rick, it's in Dayton. Next best thing to a Parallax Robotics Expo!

    http://www.qrparci.org/fdim
  • ercoerco Posts: 20,257
    edited 2016-07-03 13:02
    User Name wrote: »
    Secret confession: I finished assembling them 6/29 but haven't applied power yet. I've got BIG BIG plans. But better hang on to your cellphone for a few more days, just to be safe.



    Aw c'mon, at least test the receiver if you don't want to fire up the tx. Rx sounds surprisingly good in these videos.





  • ercoerco Posts: 20,257
    edited 2016-07-03 16:56
    Ha, this classic Radio Shack/ Archer code key (just a SPST switch) costs $40, ten times what the transceiver costs! I have this exact one up in my attic from my novice days some 40 years ago. I'll have to dig it out and get a 40m dipole up this week.

    http://www.ebay.com/itm/Vintage-Telegraph-Key-Switch-J-37-Key-and-plug-assembly-9-Morse-Code-Ham-Radio/142036472944

    I'll also dig out my WB4VVF Accukeyer. I loved building and using that! Might make a nice BS-1 project.
  • jonesjones Posts: 281
    I had one of those too (long gone now, however). I don't think I paid $40 for the Vibro-Keyer paddle that I bought in about 1970. My keyer was a circuit out of the ARRL handbook that used two 12AU7s! That's gone too, but I still have the paddle. My keyer probably used more power than your entire station will need.
  • KMyersKMyers Posts: 433
    Had one of those keys more years ago then I like to think abought, then I was WD8IIG. Built one of the Ramsey keyers worked ok at my slow speed! :-*
  • David BetzDavid Betz Posts: 14,516
    erco wrote: »
    Why not? At that price, it's worth it just for the soldering practice/therapy. I got two for the twins, natch.

    http://www.ebay.com/itm/321913864124
    This looks interesting. I suppose one could program a Propeller to key Morse code into the transmitter. How hard would it be to decode Morse code from the receiver? One would just need to detect the presence or absence of a tone on the speaker output. This could make a fun (but very slow) way to communicate between two Propellers. Sort of like the electronic equivilent of a tin can telephone. :-)

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