making/buying 680 uH inductors

[pc88]

I have a schematic for a WWVB reception indicator which calls for 3 680uH inductors.

I was wondering if this part would work (Mouser part no. 434-17-681J).

http://www.mouser.com/Search/ProductDetail.aspx?qs=rllIVGd7HzlAluYgjASlmQ==

Alternative, could I get away with something like this (cheaper but lower Q):

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=M8156-ND

Finally, if I had to "roll my own", how would you go about doing it?

Thanks!

FWIW, they are all part of LC-tanks (freq. around 60 KHz), so I figure I can compensate for inexactness in the inductance value on the capacitance side.

 

[k7elp60]

I would think they should be okey. One thing in buying or winding your own inductors, the maximum DC current is a factor. But since these have a maximum current of 170mA and it is a receiver I see no problem.

 

[mneary]

I would go with lower tolerance or higher Q. This is without seeing the circuit which could make a difference.

Can you post the WWVB circuit, or a pointer?

 

[pc88]

Here's a LTSPICE schematic. The circuit appeared in Nuts and Volts, May 2006 on page 111.

Now that I've entered the schematic into LTSpice, one problem I'm having is that I cannot reproduce the frequency response plot. The plot in the article shows a gain of 60 db at 60 KHz, but I'm not getting anywhere near that.

I uploaded a the schematic and response plot from the original article.

 

[mneary]

First problem I see (from left to right) is L4 is 703.6 nanofarads.

 

[pc88]

Henries, Farads - ack!

Okay - that fixed it - thanks!

 

[Speakerguy]

You can probably buy .68mH air core inductors from loudspeaker companies.

 

[Hero999]

You make the 700nH inductor yourself, although you could probably use a 680nH and it'd make little difference.

He's talking about the larger 680µH inductors which can be bought from many suppliers. They only have to be low current, an ESR of 10Ω is probably acceptable. I advise buying them rather than making them because they'll be much smaller and have a higher Q.