The AM Forum

Hi,

I have modified a TS850 for excellent AM - Direct feed to balance modulator (BM), and defeated the auto selection of TX filters by the hidden menu.

I came to modify my TS690S - Did the direct feed to the BM, but there appears to be no hidden menu to defeat the auto selection of TX filters. However I have found the following work around:-

Filter selection (8.83 Mhz and 455Khz) in these types of radios are performed by serial to parallel convertors. In the case of the TS690s one is on the IF board (IC3) and one on the RF board (IC3). If you make your filter selection in the normal way i.e. for AM, 8.83Mhz filter= 'Thro' and 455Khx filter = '12Khz' if you then ground the clock pins on the IC3 chips (Pin 14) no data can be sent to IC3 during transmit and as such the auto filter selection will not take place, leaving you with AM audio up to 6Khz on transmit.
It is not the most elegant solution and I have to consider the best way to tie in the grounding of pins 14 on the IC3 chips with the PTT but it does work as can be heard by the audio clips.

Does anyone out there know if there is a hidden menu to defeat auto selection of filters during transmit in the TS690S or has anyone modified the firmware to do the same thing.

Regards
G8NOF

Hi again,

I neglected in my post the thank Dave GW4GTE for his help.

Regards

Glenn