[ARC5] ARC 5 reciever backlash.

[Bill Cromwell]

Hi,

Ken Gordon has good info and suggestions there. I can add some more to 
those.

The anti-backlash design incorporated into the gears is excellent and 
similar designs are used in a lot of other gear. That can be overcome by 
sloppy bearings and more especially by dry, sticky lubricant and dirt 
that is 70 years old! I had one I had to remove from the radio and 
disassemble to get it cleaned and lubed well enough. That radio had been 
exposed to some 'extra' environmental stimulous.

An option (if computers don't mortify you) is applying your audio out 
from the receiver to the sound card in your computer running one of the 
SDR packages. Your receiver will not be an SDR. There is no I and Q 
quadrature output from your receiver. I will "mostly" work anyway. You 
can have very narrow filtering (better than most "audio filter" units. 
That wide chunk of spectrum coming through the radio will actually be a 
good thing if you use the SDR software. You will tune the range of the 
IF + audio bandwidth with the arrow keys on your keyboard or with your 
mouse. The tuning rate will be substantially improved without hacking 
your receiver to add 'bandspread'.

You can also use DSP software like "Spectran" to get the narrow 
filtering without modifying the receiver. But with straight DSP packages 
you won't get the "bandspread" effect. You set up the DSP and use the 
waterfall to identify where signals are and then use the radio's tuning 
knob (fast tuning rate) to move the signal into the filter area you have 
setup on the computer (I set mine at about 600 cps). You can also use 
the radio's tuning knob to move the signal in the display to the 
onscreen cursor for detection (no bandspread effect). That way you won't 
get gangrene or cooties from touching the computer while tuning.

The DSP package I use can narrow the audio passband to something less 
than 100 Hz and the DSP can be narrower.  Some people would rather get 
sick and die than use a computer or especially anything that says SDR. 
But those approaches work. I get better results and I don't have to hack 
the radio. The radio is doing all the heavy lifting. The computer gives 
a big boost in performance and added capabilities. And the computer is 
still not doing the radio operating - I am. I will not have a radio that 
makes qso's for me and emails me a report to tell me how much fun I am 
having and then updates my log on facebook!

73,

Bill  KU8H



On 04/23/2017 10:34 AM, J Mcvey via ARC5 wrote:
> Trying to get everything in shape, but I'm getting frustrated with the 
> ARC-5 receiver's touchy tuning.
> 1) no selectivity
> I am marginal at CW as it is, but when I have to hear two or three 
> different tones at the same time it makes it nearly impossible for me.
>
> 2) backlash.
> I haven't taken the receiver apart yet to look at the mech.
> Any suggestions before I do?
>
>
>
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

-- 
bark less - wag more