[RTTY] MMTTY-laptop problem revisited

[W5FKX - Don]

Last month I posted a question as to whether anyone had any suggestions to 
help solve an apparent RFI problem with my portable station using MMTTY and 
a new laptop. A couple or responses suggested toroids, which I have tried, 
but without any luck. I thought that I'd try once more to see if anyone 
might have had a similar experience and found a solution. Here is the 
equipment/software lineup:

- IC-706MkII, using FSK output from rear ACC connector
- Rascal interface
- USB-Serial converter (Manhattan Computer Products)
- Gateway M325X laptop w/XP Home
- MMTTY v. 1.65

When I hit the MMTTY TX button, the rig goes into TX, but the software locks 
up. Hitting the RX button does no good, and when I try to exit MMTTY, I get 
a "Program not responding" message and I have to terminate the process to 
exit MMTTY. If I then turn off the trcvr and re-start MMTTY w/o re-booting 
the PC, the trcvr goes into TX.

 I have to manually power-down the trcvr and re-boot the laptop in order to 
re-set everything. This occurs even at the lowest output power level (5w). I 
have toroids on all leads going to the laptop, as well as aluminium foil 
wrapped over the port-converter's components in the in-line plastic-hooded 
serial connector. I have tried several different antennas, both during 
portable and at-home operation. Nothing works.

Interestingly, I have no problem with PSK using DigiPan and running up to 
50w.

I have used this same setup for years with an older Gateway laptop that had 
a serial port and never had a problem, even without toroids. I also use the 
same software and a Rascal interface for my home station and have not 
encountered any problems, even at high-power.

Any more ideas would be greatly appreciated!

73,
Don W5FKX