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[wxsig] Radio Interference Question

Leon Bruner leon at ljjf.net
Tue May 15 10:07:23 UTC 2007


Hello,

I'm hoping someone can help me determine the correct final set-up for my 
just completed T-238+ and modem.  The problem is that after hooking up 
the system to the radio I do not appear to be able to transmit wx data.

Information relevant to the situation I can think of is as follows:

After assembly all the voltage checks are OK except for one:   between 
pin 4 of U101 and P100 pin 6 the voltage is 3.42 V instead of the 
specified 5 V.  I have rechecked the R109, D101, and Q100 and they are 
oriented correctly and appear to have good solder joints.  Except for 
this out of specification all else seems to work OK as far as I can tell.

I have also updated to the latest version of the firmware.

The radio I want to use is an ICOM 27H (a radio I purchased about 20 yrs 
ago).  I have wired an interface cable to connect between P100 on the 
modem board and the mic and speaker inputs to the radio.  I have 
connected as follows:

Pin on P100                    Radio  Connection

     6                           Microphone Pin 5 , PTT
     7                           Speaker  in
     8                           Microphone Pin 1, mic in
     3                           Microphone Pin 6, gnd
     4                           Speaker ground

I used this radio for packet back in the late 80s-early 90s and am 
reasonably sure I've wired the interface cable the same as was used in 
the packet system once upon a time...  Also, the amber rx LED lights 
when the squelch is turned down or when a transmission is received.

I have watched for transmissions from the T-238+ Modem and radio.  So 
far I've seen none, nor have transmissions been heard (checked on 
findu.com, using call sign NT8B-3). 
I am heard using another radio and same antenna under call sign NT8B-1.
The UART setting I'm using is 5-min avg (modem).

Does anyone have any suggestions for what might be wrong?  Is there a 
way to force a transmit to help facilitiate testing?  The help is much 
appreciated-

Regards,

Leon
NT8B




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