[time-nuts] Frequency counter recommendation

Don Latham djl at montana.com
Tue Dec 21 03:45:40 UTC 2010


Hi benevolent dictator. Please not the @#$%^& Eurocard. As you say, the
connectors and backplane cost more than the stuff on the cards (except
maybe the stuff from Hittite :-). Rather a stack of cards with .1 in.
spacing .025 pins? That way, we can put the stack in any housing we want.
If a suitable processor card (e.g. propeller or Arduino) is selected,
daughterboards can be stacked on that.
Just thinkin'. I've joined the google group.
Best,
Don

Bob Bownes
> Well said Chris. Take a look at the initial spec in the OpenCounter Gogle
> group and tell me what you think with respect to your item #1. I think the
> core counter is going to be the really difficult part of the module list.
>
> Item #2 is going to be a tough one methinks. I love Eurocard, but, as you
> say, it is very expensive, if only for the connectors. In cases like this
> I'm a fan of either repurposing commercially available connectors (PCI and
> memory DIMMS are two I have used in the past) because they can be a)
> purchased off the shelf, b) are manufactured in enough volume to make
> cheap,
> and c) are common enough that the really cheap amongst us can get them off
> of scrap boards someplace for little or nothing. The N2PK VNA is built to
> fit into a particular HAmmond enclosure that I like but again, there are
> many options. My feeling is that the enclosure should not dictate any
> functional design decisions.
>
> #3 - I've created a group and appointed myself benevolent dictator. We can
> discuss things, propose designs or design criteria, call for a concensus,
> accept, and draft volunteers to design that section to the defined spec.
> If
> there are multiple competing designs, so much the better, as long as we
> all
> agree on the interfaces. Sound like a process? Can you tell I've done this
> once or twice? :)
>
> Step one will be to agree on the overall functional spec. If we get enough
> participants, I'd like to nail that down by mid January. The next step is
> to
> agree on the interfaces between the modules. Same process, discuss,
> propose,
> draft, get concensus, close and move on.
> Then we get folks working on the individual modules.
>
>
> On Mon, Dec 20, 2010 at 8:43 PM, Chris Albertson
> <albertson.chris at gmail.com>wrote:
>
>> On Mon, Dec 20, 2010 at 2:51 PM, Dave M <dgminala at mediacombb.net> wrote:
>> >
>> .. never got off the launchpad because of their inability to come to
>> > consensus on a set of features. I had to conclude that too many cooks
>> > spoiled the broth. Everyone that had input to the project was
>> unwilling
>> to
>> > yield on anyone else's ideas.   Hopefully, our project won't degrade
>> into
>> > another such fiasco.
>>
>>
>> THAT is the number one problem to solve.  Technical issues are easy
>>
>> I think the solution is to
>> (1) chop the project up into small enough parts, each on it's own PCB
>> so that each part is "easy" and has some wider user outside the
>> project.
>> (2) Find a mechanical standard so all the PCBs can be mounted in some
>> kind of chassis.  I'm thinking now that maybe a 160-3U Eurocard would
>> be about right size.  But the parts are expensive.
>> (3) Need some sort of design process that allows everyone to
>> contribute.   And everyone can.  Projects always are lacking technical
>> writers and quality control people
>>
>> Of those a "process" and "mechanical standard", I think are the
>> hardest.   We always give managers a hard time but that is what is
>> needed.  The person who will make this happen will be a manager and
>> organizer maybe not a designer.
>>
>>
>> --
>> =====
>> Chris Albertson
>> Redondo Beach, California
>>
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-- 
"Neither the voice of authority nor the weight of reason and argument are
as significant as experiment, for thence comes quiet to the mind."
R. Bacon
"If you don't know what it is, don't poke it."
Ghost in the Shell


Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
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