[CW] USING A TWO METER RADIO TO SEND CW

[mikea]

On Thu, Jan 18, 2007 at 01:17:12AM -0500, Jim Vaughan wrote:
> I remember seeing somewhere that you could modify a two meter fm rig to use 
> cw.  Does anyone know about this or have the information.
> This is great for code practice to help other hams who don't have the code 
> to learn and also build up their speed without having to
> purchase another radio.
> 
> Any information would be very much appreciated.
> Please answer off list.
> 
> 73 and thanks in advance,

I'm answering on-list because I think it's potentially of interest to 
all the listmembers. 

Some rigs, such as the Yaesu FT-897 and FT-857, support this natively:
there's an option setting that says to send Modulated CW (audio tones)
when the key is closed while in SSB or FM modes. But these are DC-to-
daylight all-mode rigs, not 2-meter FM.

Ralph, KA5RUZ, has developed a tiny 555-chip-based oscillator that
plugs into the microphone jack of an HT or other rig that doesn't
natively support sending MCW. It requires that you keep the PTT switch
closed while sending, to keep the rig in transmit mode. Pretty much
any 555-based oscillator will do, as long as you filter the sharp
edges (fast rise and fall times) of the waveform. If you've got an MFJ
code practice oscillator, you're very nearly home free: it's just a
matter of making a jumper to go from it to your HT or other rig.

NOTE WELL: The Yaesu/Vertex VX-150 HT uses a 4-conductor 1/8" phono
plug, which is *VERY* difficult to find, and inserting the plug does
disable the built-in speaker. To use this technique with the VX-150
and its relatives, you will have to use an external speaker.

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin