[time-nuts] 10 MHz Filters
John Ackermann N8UR
jra at febo.com
Tue Dec 2 16:27:06 EST 2014
Thanks for the kind words, Dick. :-)
However, a couple of notes on the TADD-1 bandpass filter:
1. I *don't* recommend installing it unless there is a good reason. As
others have noted, any tuned circuit is a thermometer and will degrade
ADEV performance. Other than the original test unit, I haven't built
the filter into any of the several TADD-1s I've deployed in my lab.
2. The component values for the example filter in the TADD-1 manual are
wrong. I haven't gotten around to fixing that, mainly because of point 1.
And since the topic of isolated grounds has come up: the TADD-1 uses
transformer isolation on each input and output, and provides DC
isolation by putting a 10nf cap between ground and the coax shield (with
a very short path). This seems to have worked pretty well for most users.
On 11/27/2014 11:41 AM, Richard Solomon wrote:
> If you want to see how to really do it right, check out this
> distribution Amp
> on the TAPR site.
> 73, Dick, W1KSZ
> On 11/26/2014 9:08 PM, Perry Sandeen via time-nuts wrote:
>> 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.
>> 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?
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> and follow the instructions there.
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> and follow the instructions there.
More information about the time-nuts