[R-390] Alignment R-390A... simple ( ?

Roy Morgan k1lky68 at gmail.com
Tue Aug 25 18:32:12 EDT 2015


On Aug 25, 2015, at 1:17 AM, Pete Williams <jupete at internode.on.net> wrote:

> ... The  aging process led me to  make  things  a
> bit  simpler.. ...
> I recently  made  myself a  marker generator

Pete,

Thanks much for your post suggesting the marker generator.  I happen to have one here (and a URM-25F), and can try your method out.

I notice my hamfest $5 marker generator has only an RCA-plug terminated wire for output.  I plan to add some banana jacks, and a BNC jack.  There is room also for a small pot that will let me adjust the output level easily (no good step attenuator is at hand).  It seems to me that making the output adjustable is far more important than knowing what the signal level is in microvolts (or dBm).

>  from a piece in a  copy of
> Popular Electronics using a  100khz xtal and a  CD4017 chip... A  2N 2222
> is  an  oscillator  and  another for the   amplifier.

Mine is on what seems to be a commerce printed circuit board - may well be the same as yours.

> The  CMOS divider  produces outputs  at 100,  50, 20 and 10kHz with useful
> level output  markers up to  30MHz

Mine has a rotary switch to select the output frequency.

> ... for more meaningful /sensitivity
> tests one  has to  resort  to  a  sig.gen with a   calibrated  attenuator.

My URM-25 will do that nicely (along with a fixed attenuator).
 
Thanks for the tip.

Roy

Roy Morgan
k1lky68 at gmail.com
K1LKY Since 1958



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