[time-nuts] Trak 8810 Station Clock

[paul swed]

Chris
Looked at the photos and believe you do not need a down converter. The one
pix has a filter in it. dcf21r57. Its a murrata GPS bandpass filter 1575
MHz.
So that indicates its looking for a antenna. See what voltage is on the
antenna jack.

On Sat, Jul 20, 2019 at 9:58 PM paul swed <paulswedb at gmail.com> wrote:

> Chris
> What Bob was mentioning is true of the older units circa 1990s. I have
> homebrewed down converters for two older units. Essentially everything gets
> multiplexed onto the one jack so you can't really tell by looking if it
> needs a downconverter or just an antenna. A bit of a hint. If there is
> something like 12-15VDC on the jack then it needed a down converter. But
> its just a hint not a rule.
> Its funny how you find great receivers for $0 only to find out a key
> component is missing.
> Thats how I ended up with my Austron.
> Good luck
> Paul
> WB8TSL
>
> On Sat, Jul 20, 2019 at 9:00 PM Chris Quayle <syseng at gfsys.co.uk> wrote:
>
>> Hi
>>
>> > It’s a pretty good guess that a device from that era ran a
>> “downconverter” head end.
>> > They had a full RF front end out at the antenna and fed some sort of IF
>> frequency
>> > back to the unit. Various outfits had approaches to how to do it. The
>> net result is that
>> > the head end is pretty specific to this or that box (or at least series
>> of boxes).
>> >
>> > Since it’s an entirely different approach to getting things done,
>> directly replacing the
>> > head end with a modern module is going to be tough. The normal
>> alternative is to
>> > build up a downconverter. Some do it from scratch, others find a
>> similar unit
>> > somewhere and modify it to do the job. The big trick is to find out
>> exactly what the
>> > main box is looking for ….
>> >
>> > Bob
>>
>>
>> I had wondered about that, but if you look at the antenna input, it
>> looks like pretty high frequency, with a track inductor. Would
>> assume that a downconverter from gps frequency would
>> translate to baseband, but may be wrong.
>>
>> Took a few pics of the board, in case it looks familiar to
>> anyone, but it must have been used on other, perhaps marine or
>> avionics kit of the time. Problem is finding such an item, say
>> on Ebay, without taking the lid off to verify contents. Have a
>> feeling this quest may take some time :-).
>>
>> Here are the pics anyway:
>>
>> https://www.flickr.com/photos/182770787@N05/
>>
>> Regards,
>>
>> Chris
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at lists.febo.com
>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>>
>