LF: Re^n: Receiver

[DL4YHF@aol.com]

Hello,

I once had the chance to compare an old IC735, an IC706 and a TS850 running 
side-by-side connected to a tuned LF-antenna (150m long wire).

Results:
- TS850 with 500Hz and 270 Hz filter:   
   Could hear the grass grow   and   OH1TN call cq on 136kHz.
   A fine rig, as already expressed by others (and in the LF handbook).
   Considering the price I once paid for it, and for what it can be found
   nowadays on the second-hand market, I would almost buy a second
   one as a spare unit ! 

- IC735:  quite deaf, some IM products audible which were not there
   on the TS850. But still a nice rig on 160m and HF.

- IC706 ( the 'old' one, no MK2, with 270 Hz filter): 
   Very deaf on 136kHz, no matter if the preamp is on or off. 
   Turning the VFO knob OR THE VOLUME CONTROL results 
   in a hissing sound, which stops after the motion.
   Looks like the rig picks up some noise from its own serial interface
   between the front panel and the microcontroller !
   Hopefully the IC706 MK2 ( & -G) are better at 136kHz.
   At 77kHz, I cannot even hear the DCF time signal transmitter near
   Frankfurt...

Some years ago, I compared the TS570 and the TS850 on HF for CW.
There were severe blocking effects in the TS570 in a heavy crowded CW
segment, because there is not enough selectivity in the early stages
in the IF amplifier chain. The S-meter went up to S-9, but no signal 
could be heard because the DSP decided it was outside the passband.
And, with modestly narrow CW filter settings the audio from the TS570
sounded like a block flute, which is not very pleasant. Maybe there was 
something wrong with the DSP. We never did further investigations because the 
owner of the TS570 immediately traded it for a TS850...

73, 
  Wolf  DL4YHF.