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Author Topic: Send Morse on your UHF/VHF Rig?  (Read 1827 times)
KD7NDM
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Posts: 6




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« on: January 29, 2002, 01:47:47 PM »

I have been trying to find a project or a device that will generate a tone and key the ptt at the time of sending code.  I am wanting to hook this into my 440/2meter and send cw on.  I am a begginer in the Ham world and electronics.  I have found only one item that was called the Morsebox and could use any advise offered. Thank you.
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WB2WIK
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Posts: 20595




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« Reply #1 on: January 29, 2002, 02:10:18 PM »

What you describe wouldn't be CW, it would be MCW (modulated CW), using tone modulation -- which is perfectly legal on VHF-UHF, but not very popular.

I question why you'd want the tone to key your transmitter.  If each "dit" and "dah" keyed your transmitter, you'd be sending hundreds of transmissions for every brief communication...this seems kind of silly.

Normally, you'd want to do one of the following:

-Either key the transmitter manually at the beginning of each transmission, send MCW, and then unkey manually at the end of the transmission (simplest to accomplish, requires nothing special at all, just a code practice oscillator adjusted down to a proper level and acoustically coupled to the microphone, or plugged into the microphone jack to directly modulate the rig);

-Or, use a VOX circuit to automatically transmit at the inception of an MCW string, and then have a delayed "unkey," so the transmitter stays keyed in between "dits" and "dahs," and only releases (goes to "receive" mode) when you're finished with a communication, using a suitable delay to keep the rig keyed when you're "sending."

The first solution obviously involves no special equipment, just a code practice oscillator and your finger on the transmit button!

What are you actually trying to do??

WB2WIK/6
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W5HTW
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« Reply #2 on: January 29, 2002, 03:15:49 PM »

Agreed with Steve, WB2WIK, on all aspects.  Some of the hams in my area have conducted code practice on VHF (146.52) using a locking microphone (one which can be locked in "Transmit" mode) and a code practice oscillator.  

It's completely legal above 144 MHZ, but is considered "modulated transmission" so is restricted to the frequencies that permit voice (F3) operation.  Which actually means 144.1 MHZ and up.  It does not qualify as CW (which is A1 or F1)  and can not be used in the CW portions of the bands.  To qualify for F2, it would have to be as you suggest, keying and unkeying  the transmitter AND the tone, with each 'dit' and 'dah' and that's kind of inconvenient, to say the least.  Many rigs won't do it, and many won't receive the 'dits' very well due to delays in opening the squelch, etc.   At very slow speeds, 2 or 3 WPM, it might be useful.  


Of course, if you have a code program and sound card on your computer, you can put the microphone next to the computer speaker and run "machine Morse."   Or you can use a computer/radio interface and use the computer's sound card to key your transmitter's VOX circuit (if you have one - many VHF radios do not) and the delay will prevent excessive switching by the transmitter/receiver.  That would allow you to use the computer software Morse program to generate Morse code and transmit it on the radio.  

Not only is it a good way to practice code, it's just plain fun to communicate that way with those who do not have all-mode rigs that can work real CW on VHF and UHF.

Do it the simple way.  Press the PTT switch and use a code practice oscillator (or your computer software) to generate an audio signal into the microphone.  This method is legal on VHF/UHF voice frequencies, and, as noted, is bunches of fun.  Adding a foot switch, or a locking microphone, makes it much easier, for it frees one hand.  Many VHF rigs DO have VOX, and that might be a way to go, but that makes it a cross between modes, in tone-actuated keying, making it at least a cousin to F2 emission!  Either way it is legal on voice frequencies, not on CW frequencies.  (Darn!  I've got to go look up the new emission designators!)

Some kids still have those little Part 15 walkie-talkies that had the Morse code key attached and the code chart on the front of the radio.  They were lots of fun, and do the same thing you are discussing, under Part 15 regulations, usually on 27 MHZ.  

Have fun with it.  Several here are doing it intermittently for code practice and a friend wants us to hold regular Morse contacts on some simplex frequency around here, using tone into the microphone.  We'll probably give it a try!   But we'll avoid the usual simplex frequencies in use around here, and pick some "off brand" freq.  As should you, probably.  

73
Ed
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KD7NDM
Member

Posts: 6




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« Reply #3 on: January 29, 2002, 03:51:29 PM »

http://www.alphalink.com.au/~parkerp/nojun00.htm  This is the link to the device that got me thinking about how to do this. Let me know what you guys think.
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WB2WIK
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Posts: 20595




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« Reply #4 on: January 29, 2002, 04:19:21 PM »

That project looks like it would work just fine...why not just build it?

This provides what I detailed earlier, which is a VOX delay relay circuit that will key your transmitter and keep it keyed between dots and dashes, so you're not keying the rig with each dit and dah.  Perfect!

WB2WIK/6
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WB6BYU
Member

Posts: 13239




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« Reply #5 on: January 30, 2002, 11:29:55 AM »

This circuit is certainly better than some of the others that have
been published using a 555 IC for the audio oscillator:  the
audio waveform will be much easier to listen to, since the twin-T
oscillator gives a sine wave (instead of a square wave).  My
only suggested improvement would be to add some sort of monitor
speaker so you can hear what you are sending.  You might be
able to connect an audio amplifier to the oscillator output (perhaps
a pair of amplified computer speakers would work?)
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WB6BYU
Member

Posts: 13239




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« Reply #6 on: January 30, 2002, 11:32:06 AM »

Just keep an eye on the temperature of your rig while you are
sending.  Many HTs will get rather warm if you transmit for several
minutes at high power.  If you will be sending code for 10 or 15
minutes (not uncommon at the slower speeds) then you may want
to run the rig on low power.
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