[time-nuts] 10 MHz Filters

Bob Camp kb8tq at n1k.org
Thu Nov 27 12:41:45 EST 2014


Hi

We are talking about many different parts here and calling them all “transformers”.

The parts from an Ethernet line card are broadband devices used primarily for isolation. The 10.7 MHz IF transformers are designed for use in a filter. The first could be used to break a ground loop on a cable. The second could be used to knock out a harmonic or sub-harmonic. Each will do quite poorly trying to do the other one’s job.

Bob

> On Nov 27, 2014, at 11:04 AM, Joseph Gray <jgray at zianet.com> wrote:
> 
> Perry,
> 
> Just three days ago, I posted about my using transformers from
> Ethernet cards. I also summarized the results of some measurements
> using the spectrum analyzer. There was only one response, so it seems
> that what I posted was widely ignored.
> 
> Dave M - good find on Electronic Goldmine.
> 
> 
> Joe Gray
> W5JG
> 
> On Thu, Nov 27, 2014 at 8:50 AM, Dave M <dgminala at mediacombb.net> wrote:
>> Electronic Goldmine has some Pulse Engineering LAN transformers (same as
>> those used on many LAN boards) on clearance at $1.00 each.
>> http://www.goldmine-elec-products.com/prodinfo.asp?number=G17078
>> Datasheet is at http://www.datasheet4u.com/download_new.php?id=541958
>> 
>> Quite cheap, in my opinion.
>> 
>> Cheers,
>> Dave M
>> 
>> 
>> 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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