[TenTec] OMNI VI Plus, MMTTY, and FSK

[Ed]

KA5M at aol.com wrote:
> I used the FSK keying circuit specifically for the OMNI VI Plus shown on 
> http://www.aa5au.com/rttyinterface.html to build a COMM port to radio interface.  
> I used a 2N4402 PNP transistor.  As shown, pin 3 (TXD) of the DB9 comm port 
> goes through a 1K resistor to the emitter.  The base is grounded, and the 
> collector goes to Mark/Space on the rear of the OMNI VI Plus. When I try to transmit 
> RTTY, all I get is a steady tone.  The radio is not being keyed.  (PTT using 
> a 2N4401 NPN transistor work fine, no problem.)

Marsh, I use FSK with my Omni VI and it works fine. I use a straight 
thru connection with a 1k resistor in series TXD to mark/space. This was 
suggested by TT about 3 years ago. AA5AU's information is NOT correct 
for the OMNI VI or for that matter the V also. I asked Don to correct 
his false and misleading information to no avail. You do NOT need a PTT 
unless you plan on using AFSK or some other mode such as PSK.

Ed W3NR