[TRLog] Typical lid CT user

H. L. Serra hlserra@pwa.acusd.edu
Wed, 10 Sep 1997 14:57:39 -0700 (PDT)

OK George. Plenty long. I guess I didn't read my TR manual carefully
enough. I thought TR set my OMNI's adjustable internal PTT timing circuits
through the total CPU interface on the OMNI, but you're telling me TR
simply keys a second outboard keying circuit to do the PTT pre-start and

Soooo... I need a second keying line and second set of keying transistors
in order to have the TR "PTT ENABLE" feature work. Correct? 

Couldn't TR simply send the PTT pre-start and delay commands to the OMNI
CPU (via the OMNI VI [ICOM] command set) and have the OMNI do the PTT
timing and keying work internally as it is designed to do, without RFI
problems? That sounds like a more elegant solution, and requires no
additional hardware or lines which can bring RFI to the computer and foul
up TR. What say, Tree?  
73, Larry N6NC

On Wed, 10 Sep 1997, george fremin iii wrote:

> H. L. Serra writes:
> >
> >Hi George- Saw your note about PTT and TR. Does it tend to pull RF into
> >the computer on the PTT line from the computer interface connection? 
> >Moreover, how does TR know where the PTT connection is on the plug? I have
> >my radio set as "TENTEC OMNI VI" in TR. Does it know what to do inside the
> >OMNI VI interface to close PTT at key-down before keying xmtr? 73 Larry
> >N6NC (ex-N6AZE) 
> Ahhh...Let me see if I can explain this.
> TR-Log provides a PTT signal on the LPT port of the computer.
> In order to take advantage of this you need to wire up a PTT
> interface (just like the CW interface) on your LPT port. 
> The PTT signal can be set by the user (keyup and keydown delay) 
> so that the radio/amp whatever is fully keyed BEFORE any CW is sent.
> It also ensures that the relays do not drop out between dits
> at ANY CW speed. 
> The way that this PTT signal is setup on the LPT port causes
> the LPT port to more sensetive to RFI even if you are not using 
> the PTT signal.  If you are having RFI problems sometimes you 
> can cure them by setting the command PTT ENABLE = FALSE. 
> CT does not have this PTT signal and sometimes I hear that 
> the user did not have RFI in his keying port with CT - So 
> disabling PTT signal in TR-Log will make the port like CT. (no PTT)
> I of course sugggest that you build a PTT interface and use 
> it because it is way cool and a better way to key your amps/rigs. 
> Use other measures to get rid of the RFI in your computer. 
> There - was that long enough?
> -- 
> George Fremin III
> Austin, Texas C.K.U.     "It is hard to be in one place at the same time."
> K5TR                             -- Overheard at the TR-Log booth
> 512/416-7010                          at the Dayton Hamvention
> geoiii@bga.com

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