[time-nuts] 10 MHz Filters

Bob Camp kb8tq at n1k.org
Thu Nov 27 15:05:08 EST 2014


Hi

Even if you are running 50 ohm loads, with 4 outputs, a power splitter is a very real solution. You will be down 6 db on each output. If you start with +13 you will have +7 dbm. Your target devices probably are happy as can be with anything over +3 dbm.

-------------------------

If you are worrying about WWVB problems, don’t just look at the cables. Check the connectors as well. BNC’s loose shielding capability much quicker than they get to a high insertion loss. I’ve had a *lot* of grief from them over the years.

Bob

> On Nov 27, 2014, at 1:26 PM, Chuck Forsberg WA7KGX <caf at omen.com> wrote:
> 
> I have 4 or 5 devices that use the 10 MHz from my Trimble Thunderbolt.
> All but one have high impedance 10 MHz inputs, so the Thunderbolt
> can drive the lot without any amplifier.
> 
> When I put together my Thunderbolt, power supply, and filter I assumed I would
> need a distribution amp ans made provisions for it.  Turns out it is not necessary.
> 
> The real trick was locating well shielded patch cables to keep the Thunderbolt from
> jamming WWV on 10 MHz.
> 
> On 11/27/2014 08:41 AM, Richard Solomon wrote:
>> If you want to see how to really do it right, check out this distribution Amp
>> on the TAPR site.
>> 
>> https://www.tapr.org/kits_tadd-1.html
>> 
>> 73, Dick, W1KSZ
>> 
>> 
>> On 11/26/2014 9:08 PM, Perry Sandeen via time-nuts 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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>> 
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> 
> -- 
>     Chuck Forsberg WA7KGX   caf at omen.com   www.omen.com
> Developer of Industrial ZMODEM(Tm) for Embedded Applications
>  Omen Technology Inc      "The High Reliability Software"
> 10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430
> 
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