[NLRS] Would like to buy a 10Mhz reference...

[Dr. Gerald N. Johnson]

Last year Paul Wade published an article on a simple way to use GPS to 
discipline a VCXO. 
www.w1ghz.org/small_proj/A_Flexible_VCXO_Locking_Board.pdf It depends
on a gps with a 10 kHz output, like many from Navman/Jupiter. Right now 
there is a seller of Jupiter Pico on epay for $20 plus shipping. Paul 
sells the bare board for $6 plus shipping. A decent VCXO is under $10 
(and with careful adjustment of the VC port may be all you need at VHF 
if its environment is controlled). The PICO is tiny and the connectors 
are smaller yet but the seller does include the mate for the 0.5mm 
interface connector and an antenna cable and off epay sells a circuit 
board to convert from that spacing to hand solderable spacing. I have 
two of Paul's boards on hand (one plain, one VHF) and two Jupiter Picos 
and two of those connector boards arrived today. My order of the logic 
chips for a couple projects in in the mail from DigiKey at the moment.

There is potential for VHF, UHF, or microwave transmissions to knock the 
GPS out of lock. It may require better filtering of the GPS antenna 
(external to the Jupiter) and the station transmitters. That I have to 
learn. It that is a problem I'll have to stick with using the project 
for receiver markers and for checking my counter standards.

If the GPS isn't messed up by transmitting that would be a super 
solution giving a million times better precision than needed at VHF.

I'm mostly of the opinion that a TCXO or VCXO or a combined product 
available from Mouser or DigiKey for an almost reasonable sum protected 
from wind, rain, sun, and drafts will be adequate while the oven 
controlled oscillator will do fine and the GPSDO will do extremely well. 
I'm looking at making markers for up to 78 GHz and there a Khz drift of 
the 96 MHz oscillator makes 782 kHz error and the GPSDO will be useful.

Then there are oscillators like the HP10544 and HP10811 that are good 
enough if parts per billion is close enough. Better than the $3 VCXO, 
and poorer than the GPSDO.

Thing about 10 MHz for a standard is that crystals in that frequency 
range historically have the best stability and aging compared to lower 
and higher frequency crystals. That's a big part of why 5 and 10 MHz are 
commonly used as references.

73, Jerry, K0CQ


On 11/13/2013 4:54 PM, Gregg Lind wrote:
>
>
> I suspect that this group has many of these....
>
> I am looking for a 10 Mhz reference I am new to VHF Rover activity and
> happen to realize that I needed one this past June for the DEMI transverter
> and was able to hack together a DDS solution this had its issues (bumped
> the knob, and some drift). I want a plug it in and just have it work
> solution (no programming needed). I am trying to minimize the issues I had
> from this last roving event, and looking for simplicity I would like a low
> cost 12 volt input and get 10 Mhz out... Also I am looking for a cheaper
> solution I am not planning anytime soon for 10 Ghz etc... .
>
> If anyone has one that would like to sell I would appreciate it.. I am
> focus on building other things for the rover, getting more power on 2
> meters etc,,,  so I just don't have the time to design/build ... Also I
> have to say I am a software developer not a hardware person...
>
> If there is a kit (beyond just a printed circuit board) that you would
> recommend I found a number of them but I really don't want to order the
> parts myself, It should be a complete kit with PWB/parts as this is a
> better for me... If you have a link please send to me..
>
> If there is something that you have built and do need any more this would
> be great... I am willing to offer a fair price..
>
> Gregg Lind
> KC0SKM
> gregg at thelinds.net
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