[ICOM] Digital Interface Problems

[KE5CTY Bob]

So I guess I will need to unplug the mic when I do digital
stuff in that case. I am using the EX-1514 external VOX
unit so is the mic still hot to the rig even though the
VOX is turned off or do I need to completely unplug it?

As far as "RF intrusion" will that go away if I do an
opticoupler like a 4N25 FOR THE PTT and the audio
isolation transformers on both of the other lines?

I searched on FairRadio and Mouser and found the 4N25 but
could not find anything on an isolation transformers for
the audio lines.

73 fer nw,
Bob
KE5CTY (old calls WB5ZQU - WY5L)
10X# 37210, FP#-1141, SMIRK#-5177
http://www.qsl.net/ke5cty/
Code may be taking a back seat for now,
but the pioneering spirit that put the code
there in the first place is out front of it all.


> -----Original Message-----
> From: icom-bounces at mailman.qth.net 
> [mailto:icom-bounces at mailman.qth.net] On Behalf Of
gfiber at comcast.net
> Sent: Wednesday, August 24, 2005 4:06 PM
> To: ICOM Reflector
> Subject: Re: [ICOM] Digital Interface Problems
> 
> 
> Bob,
> 
> RFI intrusion. The audio input in the back, ACC ! jack,
is 
> high impedance where the mic is 600 ohms. You may need
to do 
> some isolation work with audio transformers. Its quite
common 
> on the Icom products I cross that bridge hundreds of
time 
> when I worked for Icom.
> 
> Now also remember the mic element is hot, it is not
switched 
> with the PTT so having a mic plugged into the front of
the 
> rig while keying from the ACC 1 jack you will also pick
any 
> audio that is about in the shack.
> 
> Gary K8IZ. 
> 
> -------------- Original message -------------- 
> 
> > Any ideas what could be wrong here?
> > 
> > I have interfaced my rig for digital operation as
> > described below and it seems all is well with one
slight 
> > problem noted at the bottom: 
> > 
> > SET UP:
> > 
> > -----
> > ----- 
> > Rig control (COM 2): 
> > Works great on all logging software. 
> > 
> > I am using a CT-17 with my IC-728 (same as the 729 w/o
> > 6mtrs) 
> > Hooked up on COM 2 (9 pin serial). 
> > I have the "PTT through Radio Command" (not selected).

> > "Allow external interrupts" (not selected). 
> > "Radio PTT via Command" (not selected) 
> > ----- 
> > ----- 
> > 
> > -----
> > ----- 
> > CW keying (COM 1) 
> > Works great with all logging software for CWkeying. 
> > 
> > Auto CW Keying of Rig (COM 1) "DTR=CW":
> > I made a little homebrew 9pin interface (limiting
circuit 
> > transistor ect in the jacket) so I am using with
"DTR=CW" 
> > hooked straight to my CW input jack at the back of the

> > rig. 
> > ----- 
> > ----- 
> > 
> > -----
> > ----- 
> > AFSK to rear panel (ACC1): 
> > (NOW WE GOT TROUBLE) 
> > I *tried* to hook the Audio up for the Digital Modes: 
> > 
> > 1) Went directly from the fixed audio output on the
rear
> > of the rig to the audio input of the computer
soundcard 
> > for decoding. 
> > (ADJUSTED/TESTED NO PROBLEMS DECODED ALL MODES WITH
ALL 
> > LOGGING SOFTWARE) 
> > 
> > 2) Setup DTR for PTT into ACC1
> > (ADJUSTED/TESTED - works great and keys the rig) 
> > 
> > 3) Went from computer's soundcard output to the rig's
> > audio input on the rear panel. 
> > (ADJUSTED/TESTED - SEEMED TO WORK GREAT BUT WILL 
> > EXPLAIN) 
> > 
> > 1) With the ACC1 plugged into the rear panel and the
mic
> > plugged into the front panel through the external
IC-1514 
> > VOX BOX. A station on 20 mtr bpsk reported *very hot* 
> > signal and spurs from my station on the band. So I
made 
> > further adjustments. He said it was not better. 
> > So I QRT'd pending further investigation. 
> > 
> > 2) With the ACC1 jack still plugged into the back of
the
> > rig and using the microphone on the front panel
(properly 
> > set for good audio), reports are that I am distorted
so 
> > much so - they don't even know who is calling them. 
> > 
> > 3) If I unplug the ACC1 jack the SSB audio distortion
> > immediately goes away and my signal is reported to be
very 
> > good audio quality. 
> > 
> > 
> > 73 fer nw,
> > Bob 
> > KE5CTY (old calls WB5ZQU - WY5L) 
> > 10X# 37210, FP#-1141, SMIRK#-5177 
> > http://www.qsl.net/ke5cty/ 
> > Code may be taking a back seat for now, 
> > but the pioneering spirit that put the code 
> > there in the first place is out front of it all. 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > ----
> > Your Moderator: Dick Flanagan K7VC,
icom-owner at mailman.qth.net 
> > Icom Users Net: Sundays, 1700Z, 14.316 MHz 
> > Icom FAQ: http://www.qsl.net/icom/ 
> ----
> Your Moderator: Dick Flanagan K7VC, 
> icom-owner at mailman.qth.net Icom Users Net: Sundays,
1700Z, 
> 14.316 MHz Icom FAQ: http://www.qsl.net/icom/
>