{"id":7085,"date":"2021-03-22T14:30:00","date_gmt":"2021-03-22T03:30:00","guid":{"rendered":"https:\/\/www.homebrewradio.us\/blog\/2021\/03\/22\/my-hodgepodged-morse-audio-tone-into-the-mic-jack-creates-j2a-not-a1a-basta\/"},"modified":"2025-07-21T22:13:20","modified_gmt":"2025-07-21T12:13:20","slug":"my-hodgepodged-morse-audio-tone-into-the-mic-jack-creates-j2a-not-a1a-basta","status":"publish","type":"post","link":"https:\/\/www.homebrewradio.us\/blog\/2021\/03\/22\/my-hodgepodged-morse-audio-tone-into-the-mic-jack-creates-j2a-not-a1a-basta\/","title":{"rendered":"My Hodgepodged Morse: Audio Tone into the Mic Jack Creates J2A not A1A. BASTA!"},"content":{"rendered":"

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In SolderSmoke podcast #229<\/a> Pete and I were discussing my rather flaky effort to turn the Hodgepodge BITX40 Module into a CW rig by injecting keyed 700 Hz audio into the mic jack (see video below). We got some very helpful responses from ND6T and VK2EMU: <\/b><\/span><\/p>\n


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Hi Bill,
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You mentioned generating CW by modulating SSB: Collins did that in their
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first SSB transceivers, I believe, as did SGC, but the results were less
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than optimal. The problem is that you are involving the audio chain and
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modulator. You know from experience how difficult it is to maintain low
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intermod there and the tone is no exception. So we end up with lots of
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spurs within the filter passband and then also have the opposite
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sideband suppression less than perfect. If you check your transmitted
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signal with a spectrum analyzer or SDR you can easily see the nasties.
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Listening to a CW signal thus generated makes it obvious unless it is
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buried way down in the noise. It IS a valid CW signal (not MCW) since it
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is (almost) a single signal. However, in actual operation it doesn’t
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work very well.
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I know because I have done that. I bought one of Farhan’s original
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BITX40 boards and wanted to put it on CW. I ended up injecting a keyed
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signal from one of the spare clocks on the Si5351 into the RF amplifier
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chain (thus avoiding the above stated problems) but still had garbage
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from the audio and IF stages. I fixed that by shorting out that signal
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during transmit by a transistor to ground. That was documented on your
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BITXhacks website: http:\/\/bitxhacks.blogspot.com\/2017\/02\/ <\/a>and on my
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website: http:\/\/www.nd6t.com\/bitx\/CW.htm <\/a>. It has been a while, eh?
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…<\/b><\/div>\n

Don, ND6T<\/b><\/span><\/p>\n

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Hi Bill and Pete,<\/b><\/span><\/p>\n

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With putting an audio oscillator into you hodgepodge radio, your transmission is not the same as a standard CW rig.<\/b><\/span><\/p>\n

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If we have a transmitter as described in the ARRL handbooks from the 1940’s or 1950’s, (or even the Michigan Mighty Mite) it is a crystal oscillator and maybe a PA tube. By keying either the oscillator and\/or the final PA on and off, then we can send Morse code as ICW Interrupted Continues Wave. If we check the list of emission designators, we have A1A.<\/b><\/span><\/p>\n

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However, if we feed a tone into a SSB transmitter, then we have J2A.<\/b><\/span><\/p>\n

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At the other end it may sound the same, but because it is created in a different way, it has a different designation. <\/b><\/span><\/p>\n

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A quick look at Part 97 shows that J2A and J2B are classed as CW, so you are in the clear. However, if you put a tone oscillator into an AM signal to send CW, then that would be classed as A2A and not classed as CW, but as MCW. MCW can be used on 6 meters and above, but not HF.<\/b><\/span><\/p>\n


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SITS.<\/b><\/span><\/p>\n

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73 de Peter VK2EMU<\/b><\/span><\/p>\n

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