[R-390] Filters

[Bob Camp]

Hi

If you re-wind the solenoid coils you would need the correct stranding *and* insulation Litz wire. The transducer coils resonate with the caps on the end of the transformer. Winding tension will also play a part in the value you get when you are done. On the same machine with the same source of wire, you can hit the same inductance within 1 or 2 percent. Q will be amazingly consistent, but probably not to better than 5%. Change pretty much anything and you will have to fiddle to get back there. Ben there done that on a lot of production coils.

Bob

On Feb 16, 2013, at 3:18 PM, KA9EGW <ka9egw1 at britewerkz.com> wrote:

> Could one unravel a length of Litz wire to get the requisite wire, or is it something like phosphor bronze?
> 
> On 2/16/2013 2:09 PM, Graham Baxter wrote:
>> There does seem to be a lot of interest in the doughnuts at the expense of
>> the intriguing physics of the filter!
>> 
>> It is my recollection that the filter was completely symmetrical. If you
>> can't see the wire, it is probably broken. That is sad news, but hopefully
>> someone will be able to supply a filter with bad coils but intact mechanics.
>> 
>> Graham
>> G8OAD
>> 
>> On 16 February 2013 19:55, quartz55 <quartz55 at hughes.net> wrote:
>> 
>>> I get the feeling like no one is really reading my posts so I may quit
>>> dealing with it, too bad for someone that wants to rebuild filters.  But I
>>> will post pictues on my photobucket account for anyone that is interested.
>>> 
>>> Here's a picture of what I think is the center wire attached to the second
>>> resonator disk on the top (output) end of the filter.  On the bottom end
>>> (input), I don't see the wire like that, but I have not yet pulled out the
>>> coils on that end, the center wire may be coming off the end disk there and
>>> that's why I don't see it in the resonator disks.
>>> 
>>> 
>>> http://s251.beta.photobucket.com/user/DogTi/media/R390A/filtertopcenterwire_zps1e973e91.jpg.html?sort=3&o=0
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> 
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