wrote:
Comments on this receiver from others are welcome.

I'm not Pete, but I have owned an R-70 for a long time (20 years?). My
take on it is pretty much what you seem to think. The AM detector
leaves something to be desired. It sounds a bit distorted.

I know that Sherwood sells an R-70 synchronous detector. I haven't got
$400 to throw at this, to tell whether it's worth the money. I will say
I've yet to hear anything negative about their products.

I have the CW filter, and the FM board. Sideband, CW, RTTY, and FM all
work quite well. The Notch and PBT are very good.

I have some microcontroller chips and I'm thinking of writing some
software to handle the four bit strobed interface in the back of the
unit. I'm not sure how complex it is, but I feel I'm about to find out.

DE AB3A

Appreciate the comments Jake! As far as the AM detector goes (D74), I
was able to improve the distortion issues considerably by using a 1 Meg
resistor connected from the -10V rail to the diode's cathode. The AM
clarity was noticeably improved as was the low signal S/N ratio. Terry
Fugate from the Yahoo Kenwood R-2000 group did numerous experiments
with different detector diodes and biasing them in his R-2000 and
achieved some respectable results. It was just pure luck that the R70
had a negative rail for direct biasing with just the addition of a
resistor.

Frank
K3YAZ
Tucson


Jake Brodsky wrote:
wrote:
Comments on this receiver from others are welcome.

I'm not Pete, but I have owned an R-70 for a long time (20 years?). My
take on it is pretty much what you seem to think. The AM detector
leaves something to be desired. It sounds a bit distorted.

I know that Sherwood sells an R-70 synchronous detector. I haven't got
$400 to throw at this, to tell whether it's worth the money. I will say
I've yet to hear anything negative about their products.

I have the CW filter, and the FM board. Sideband, CW, RTTY, and FM all
work quite well. The Notch and PBT are very good.

I have some microcontroller chips and I'm thinking of writing some
software to handle the four bit strobed interface in the back of the
unit. I'm not sure how complex it is, but I feel I'm about to find out.

DE AB3A