[time-nuts] TAPR TADD-2 PIC frequency divider

[John Ackermann N8UR]

Magnus, thanks for the nice comments!

Regarding the case, yes, the form factor generally matches the TADD 
enclosure, but since that's a generic box we couldn't do much about the 
LEDs or the ARM switch.  My thinking was that the LEDs could be mounted 
off-board if necessary, and I'll update the manual to indicate that.

Since the TADD enclosure has two DB-9 cutouts, one nice option (which I 
haven't tried yet) would be to wire the LED, the 5/10 MHz jumper, and 
the ARM switch connections to a DB-9 and mount that in the enclosure, 
then mount the LEDs and jumpers to a mating connector.

Finally, the manual is very much a work in progress... I had to choose 
between getting the kits put together so we could ship before the Dayton 
Hamvention, or getting fully polished docs finished, and chose to move 
ahead with the kitting.  I'll be working on improving the manual shortly.

John
----

Magnus Danielson said the following on 05/22/2009 07:33 PM:
> Fellow Time-nuts,
> 
> I acquired myself two TAPR TADD-2 PIC frequency dividers as soon as they 
> hit the list as orderable. Tonight I had the pleasure of completing the 
> first one.
> 
> For a beginner, this kit should be fairly simple. You need to have some 
> ability to solder and read resistor and capacitors, even if most 
> capacitors comes in separate bags (pretty neat brown bags, but hard to 
> open without ripping the lid partly off). The manual could give better 
> hints for the beginner, but it is nothing major at all.
> 
> Since I fail to fall into the beginner group, I must say that it was 
> pretty straight forward to build it. The double-sided, silkscreened and 
> plated hole PCB made this as simple as any other modern kit and it is 
> easy to make the mounting look good. I was supprised how well my 
> resistor-leg bending was still up to speed and accuracy as they all went 
> in quickly and smoothly. Everything went very smoothly.
> 
> So, at last... everything mounted and time to power up. Without input it 
> sits there quitetly. I hooked it up to the time-base output of my SR-620 
> and it kicked alive directly. 10 kHz, 1 kHz, 100 Hz, 10 Hz, 1 Hz and PPS 
> all just ticked away as expected. I hooked over to a 5 MHz source, the 
> OCXO (TOYO oscillator of unknown specs) from an Ericsson AXE-10 station 
> that I keep heated at the labbench with a BNC hanging free, and sure 
> enought everything was half-rate including the PPS LED (very useful), 
> but just unplugging the 5/10MHz jumper fixed that quick enought.
> 
> A few items of criticism is in place, from a practical point of view. 
> The TADD-2 does not perfectly match the TAPR TADD-series box. I was able 
> to sneak out the PPS through the DC input hole, and the ARM and SYNC 
> LEDS is way in there, so a similar approach was not possible. The 5/10 
> MHz jumper should possibly be made into a toggle-switch. None of those 
> fits the casing, but using one of the DB9 holes should fit it nicely. 
> The other DB9 hole could be fitted with a suitable DB9 connector for 
> power. None of these things is a show-stopper, but of mild details which 
> could have been made better and very simple hacks will allow for a more 
> versatile setup, for those wishing to use their TADD-2 as a lab-device, 
> where as for fixed setups it is of close to no consequence.
> 
> I only made a quick attempt to measure jitter, but it is way down there 
> around ps or so. It was just an indicator measurement anyway. I will 
> make some more propper measurements and analysis.
> 
> Regardless, I think it is a nice kit and should allow for easy 
> lab-ability for most time-nuts. I particularly like the simultanous 
> outputs which is jumperable to suitable outputs and the 5/10 MHz jumper. 
> The PPS LED allows for a quick view and the ARM/SYNC should allow for 
> synchronisation. It fairly well fills a gap in my set of gear and should 
> do that for others too. Doing picket fence exercises becomes trivial 
> with one of these.
> 
> Good work John, Tom and others that feel involved.
> 
> Cheers,
> Magnus
> 
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