[time-nuts] 10 MHz Filters

[Chris Albertson]

I'm not much further along then you but I did find a few things...

1) You can buy/salvage good quality 10.0 MHz transformers form networking
equipment designed for 10BaseT Ethernet.  These are designed for galvanic
isolation and are used in old 10baseT routers and switches.  Newer Ethernet
works are 100 and 1000 Mhz but the older version was 10 MHz.   I have a box
of salvaged parts I removed from junked routers.  These transformers are in
wide DIP packages with 0.1" lead spacing.

2) Cheap 10MHz crystals need to be measured, sorted and matched by hand.
 And then you want to keep the temperature from moving around to much.
Before I owned a GPSDO and a two channel scope I used to think the cheap
crystals where all exactly "spot-on"

3) it is really easy to build a temperature controller using a $2 8-pin uP
and a few lines of code.  The 8-pin uP will have a few analog inputs and
outputs and even pins left over for status LEDs.

On Wed, Nov 26, 2014 at 8:08 PM, Perry Sandeen via time-nuts <
time-nuts at febo.com> wrote:

> List,
>
>
>
> I have seen on the net a 10 MHz filter using 10.7 IFtransformers but have
> no idea how well they would work for isolation with thenew style Lucent
> boxes.
>
>
>
> Thoughts?
>
>
>
> On Ebay venders are offering 10 MHz crystals for almostnothing if you buy
> 30.  My question wouldthese be good for making some type of simple ladder
> filter?
>
>
>
> In his article *Modifying Lucent RFG-M-RB Rubidium FrequencyStandard* the
> author used a 10MHz filter that was taken from an old 10MbitEthernet LAN
> board. The part number he used was 20F001N and I found them onEbay for low
> prices.
>
>
>
> Now I don’t have any access to any old ethernet LAN boardsso I’d have to
> build from scratch.
>
>
>
> Does anyone of these methods have an advantage over theothers on the new
> style Lucent boxes or in the making of a small distributionamplifier with
> good isolation?
>
>
>
> Regards,
>
>
>
> Perrier
>
>
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-- 

Chris Albertson
Redondo Beach, California