[RTTY] MMTTY-laptop problem revisited

[Ed]

W5FKX - Don wrote:
> 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

Don, any chance that both RTS/DTR are being set high by MMTTY ? I use a 
cheapy USB from Walmart that works just fine on my IBM laptop. I would 
try and swap out the USB and double check the MMTTY settings. I would 
also think about a VOM to check the DTR/RTS voltages on transmit.

Ed W3NR