Dave Platt wrote:
I'm about to build a cable to go from my TNC (MFJ 1270) to a Yeasu
VX-1R. The diagram for this cable is as follows:
http://www.packetradio.com/!TNCables/5PD2YVX.gif
My question is this. What are the values for the capacitor and
resistor listed on this diagram?
I'd suggest 2.2k ohms for the PTT current-limiting resistor (it's
what's used in their speakermikes), and a .1 uF ceramic or filmcap for
the DC-blocking capacitor.
A word of caution re building this specific sort of cable yourself.
I've found out (the hard way) that the 4-contact 3.5 mm plug sold by
Mouser does _not_ work well with the Yaesu VX-5R. The Mouser plug has
a fairly broad metal "shoulder" at the base, and this hits the outer
(higher) rim of the rubber sealing ring around the VX-5's speakermike
jack and prevents the plug from being inserted to its full depth. As
a result, the plug doesn't make good contact with the jack and (in my
setup at least) doesn't transmit properly.
The plugs that Yaesu (and other manufacturers) use, have a narrower
metal shoulder at the base, which fits nicely into the outer rim of
the sealing ring and seats down nicely against the inner rim.
Unfortunately I haven't found a commercial retail source for these
narrow-shoulder 4-contact plugs. The only source I can suggest is to
buy a VX-5/VX-1 cloning cable and cut it in half.
I built one of the Mouser plugs into a TinyTrak adapter cable, and
wasn't able to get the VX-5 to key up properly. I tore apart the
cable, rewired it with two separate 2.5mm/3.5mm plugs, and bought the
Yaesu VX5-to-TNC adapter. This combination works quite well.
I don't know if the VX-1 has the same "narrow shoulder" plug/socket
problem as the VX-5 does, but I'd suggest checking it before you go to
a lot of effort wiring up the cable.
I've had the same problem with handheld computer plugs.
My solution was to chuck it in the lathe and cut down the diameter
as required.
mike
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