[minima] Re: LPF with molded inductors
- From: Arv Evans <arvid.evans@xxxxxxxxx>
- To: minima@xxxxxxxxxxxxx
- Date: Tue, 4 Feb 2014 16:38:06 -0700
Kevin GW4WOV
I too have a Beach-40, and am working (slowly) on a 10 meter
version using a 28.636 MHz oscillator. If 10 meters works well
I plan on doing something similar with a 14.318 crystal for 20
meters.
My concern regarding molded inductors is their close approximation
of loopstick antennas used in BCB receivers. Probably noting to
worry about though for normal signal levels. If there is any problem
it would probably show up in presence of nearby strong signals, or
if one were squeezing all the sensitivity out of the rig doing weak signal
work, something like QRSS or WSPR. with very low power levels.
Any potential problem might be minimized by an EM shielded chassis.
My suggestion is to try it. If it works we all learn something. If it
does not work, we all still learn something. Molded inductors are
not all that expensive and are usually available in a wide variety of
inductance values. Might be interesting to build two filters, one with
toroids and the other with molded inductors. Relay switching
between filters could support easy A/B comparison of performance
under varying conditions.
Arv K7HKL
_._
On Tue, Feb 4, 2014 at 4:18 PM, Kevin Williams <k.p.williams@xxxxxxxxxxxx>wrote:
> Hi Arv, Peter VK3YE uses moulded rf chokes in the lpf of his beach 40
> rig, I've built the rig and can report that the chokes work very well
> running at about 2 watts output - food for thought perhaps?
>
> 73 Kevin GW4WOV
>
> *From:* Arv Evans <arvid.evans@xxxxxxxxx>
> *Sent:* Tuesday, February 04, 2014 8:32 PM
> *To:* minima@xxxxxxxxxxxxx
> *Subject:* [minima] Re: LPF with molded inductors
>
> 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
>
Other related posts:
