[minima] Re: LPF with molded inductors
- From: Arv Evans <arvid.evans@xxxxxxxxx>
- To: minima@xxxxxxxxxxxxx
- Date: Tue, 4 Feb 2014 13:32:47 -0700
Paolo and Ryan
Non-toroidal inductors do not have the closed magnetic field of toroidal
ones. This could make them susceptible to external signal pickup
and to unwanted coupling between inductors.
But having said that, I do not know of anyone who has tried using small
molded inductors in place of toroidal ones. It could be an interesting
experiment. Possibly the potential problems are so small as to be
inconsequential.
Arv K7HKL
_._
On Tue, Feb 4, 2014 at 1:15 PM, Ryan Kingsbury <ryan.kingsbury@xxxxxxxxx>wrote:
> Hi Paolo,
>
> I was wondering this myself as I was looking at non-toroidal inductor
> sources earlier today. One of my long-term goals is to miniaturize the
> minima design so that it is something small/light I can take on some of my
> adventures abroad. Being able to leverage molded, or even SMT, inductors
> would be a huge win both for space efficiency and cost.
>
> The AADE filter design tool can take non-ideal Q as well as component
> tolerances. A monte carlo sim can be run to see how sensitive the design
> is to these non-ideal characteristics. I'll try to cook up some plots in
> the next day or so to share with the group.
>
> 73,
> Ryan
>
>
>
>
> On Tue, Feb 4, 2014 at 1:25 PM, Paolo Cravero <paolo.cravero@xxxxxxxxx>wrote:
>
>> Hello MINIMAlists.
>> I have been lurking and learning so far, while gathering components to
>> assemble my own MINIMA.
>>
>> Looking at the two LPFs with toroids and the declared exciter power
>> output in the order of milliWatts, why not using molded inductors for them?
>> Q will be lower (around 10 to 25 per inductor), but in case another lowpass
>> section can be added at a fraction of the cost of another toroidal core.
>>
>> What else am I overlooking? Is a Q=10 too low for an effective LPF in
>> MINIMA?
>>
>> 73,
>> Paolo IK1ZYW
>>
>> PS: common values are 680, 820 and 1000 nH
>>
>> --
>> GQRP #12058 + http://www.paolocravero.tk + I QRP #476
>> FT-817 External -:-Knob-:-Display-:-Keypad-:- at http://bit.ly/luE4pv
>> FT-8x7 -:- CAT-to-Bluetooth dongle -:- status at http://bit.ly/VtE3c4
>>
>
>
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