[time-nuts] Re: Looking For An Antenna

[va2hdd at ebox.net]

Hi Chris.

As Tom said before these units are cheap and abundant because they can 
not be used as time reference even if you do find an antenna.

To make things worse the antenna itself is active (i.e. amplified) with 
a down converter that will bring down the 468 MHz signal frequency to 
around 40 MHz (around that !) and that is the frequency that the 
receiver expects. You can find in the easily found service manual. So it 
will not be an easy task to replicate it even if you would want to try, 
and to make thing worse the original ones are really rare and expensive.

TrueTime made a converter called the G2G that would use the GPS signal 
and translate it to the signal the 468DC expects to get from the 
original antenna.  They are so rare I've been trying to purchase one for 
years and never saw one listed.

But all is not lost, with an Arduino, a PIC or a RaspberriPi, a small 
GPS receiver and a bit of work it can be modified as GPS based clock.  
Or you can use NTP to synchronise your RaspberriPi.

Lots of fun for long winter nights !

Claude

Le 31/01/2022 22:02, kyrrin at bluefeathertech.com a écrit :

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> I used to own/use a 468-DC. They are, unfortunately, useless now
> 
> because NOAA stopped transmitting the UHF-based time code over the GOES
> 
> satellites in the early 2000's (this is, very likely, why it was so 
> cheap).
> 
> In short ... Even if you got a perfect antenna for the unit,
> 
> there's nothing for it to receive. I believe you'd be wasting your time
> 
> and money (unless you want to get -really- adventurous and try adapting
> 
> its innards to sync off GPS).
> 
> Sorry to be the bearer of bad news...
> 
> On 31-Jan-22 18:32, NoName via time-nuts wrote:
> 
>> I'm new to the group.  I'm looking for an antenna for a Kinemetrics
> 
>> 468-DC.  I only paid a few bucks for the unit and all the surplus
> 
>> companies want 800-900USD for an antenna.
> 
>> Does anyone have a source for a reasonably priced antenna, or, has
> 
>> anyone built one that they would care to share the details on.
> 
>> I appreciate anything I can learn,
> 
>> Chris