[Heathkit] Audio filter on HR-10B

[Bwana Bob]

The SCAF has a really steep rolloff, compared to conventional OP-amp 
filters. I'm going to order a SCAF soon myself. I never used an HR-10 
with my DX-60A. When I needed a better receiver (original was a Heath 
GR-91, a miracle that I made any contacts at all), I opted for a used 
Hammarlund HQ-100A. The HQ-100A does not have a crystal filter but it 
does have a Q-multiplier. I always wondered if an HR-10 would have done 
better.

You know, it seems odd that the DX-60 and HR-10 combination did not have 
a provision for sidetone.

Anyway, they are a classic pair. Heath must have sold many thousands to 
novices.


				73,

				Bob WB2VUF

TJRachwal wrote:
> Hello all,
>     After posting about mods for improving CW selectivity and other mods 
> and receiving many responses I decided to follow the advice of adding 
> and audio filter rather than making mods to the HR-10B.  It was a good 
> move and a very good suggestion.  I opted for the SCAF filter from Idiom 
> Press rather than the MFJ much cheaper filter.  The filter arrived 
> within three days (Oregon->Mihigan) and in about 15 minutes was hooked 
> to the HR-10B.  Wow!  The performance difference is amazing!  It wasn't 
> "quite" the same as the 500 hz filter but leaps and bounds over the 
> "wide as a barn door" front end in the HR-10B.  I could copy CW stations 
> clearly that were down in the mud without the filter and not workable.
>     Since I didn't have an MFJ to compare it against I can't say the 
> SCAF by Idiom press is any better but it has made the use of the HR-10B 
> much more enjoyable and I look forward to many FB CW QSOs with the 
> DX-60B, HG-10B and HR-10B.  By the way, an xtal calibrator (HRA-10-1) is 
> on the way for the HR-10B; station complete!
>     HR-10B $80.00; SCAF wired and tested $140.00; enjoyable QSOs, 
> memories of days gone by....priceless!  Thanks to all for their advice 
> and help.
> 73....Ted K8AQM
> 
>