Message	Date	From	Subject
675	2007-04-28 06:17:40	Ed Almos	Binocular Core Selection For H-Mode Mixer
A quick question. Which would be the best binocular core to use on an h-mode mixer working at HF, a BN43-2402 or a BN73-2402? Edward Almos HA6SST
676	2007-04-28 09:38:43	Baruch Zilbershat...	Re: Binocular Core Selection For H-Mode Mixer

677	2007-04-29 12:12:40	Giancarlo	Re: Binocular Core Selection For H-Mode Mixer

678	2007-05-01 01:22:00	Ed Almos	Re: Binocular Core Selection For H-Mode Mixer
OK, thank you for the replies. I have some type 43 cores in stock and can go ahead with the project. Somebody told me that type 73 cores must be used in this applicati
681	2007-05-01 14:48:41	Giancarlo	Re: Binocular Core Selection For H-Mode Mixer

685	2007-05-01 16:09:35	Jim Miller	Re: Binocular Core Selection For H-Mode Mixer
see www.w8ji.com who recommends 73 mix for receive front end apps. 73 jim ab3cv ----- Original Message -----
687	2007-05-01 16:31:24	Kevin Purcell	Re: Binocular Core Selection For H-Mode Mixer
In this article? <http://www.w8ji.com/core_selection.htm> > I mainly use 73 material for receiving applications in LOW POWER > applications between .1 and 30 MHz. 73 and similar core materials > generally minimize the turns count required without inducing > excessive loss. One of the best indicators of correct core > selection is looking at the turns required. You'll notice most of > the transformers I use have only one or two turns for every 100 > ohms of impedance. My 75 to 450 ohm Beverage transformers, for > example, only require two-turn primary and 5-turn secondary > windings. A low "turns count" is a good indicator the correct core > size and core material is being used. and (remember he's talking about TX baluns here) > At higher power levels, it is necessary to move to lower loss > tangent and higher curie temperature materials like 65, 61, or (in > extreme cases) 43 materials. Even a fraction of a dB loss produces > significant heating in small cores when power level is in the > kilowatt range. The loss DIFFERENCE in non-resonant applications > between lower and high ui ferrite cores isn't significantly > different, but heating can be much less! Of course there's <http://www.amidoncorp.com/aai_multiaperture.htm> <http://www.amidoncorp.com/aai_ferritecores.htm> > MATERIAL 43 (µ = 850) High volume resistivity. For medium frequency > inductors and wideband transformers up to 50 MHz. Optimum frequency > attenuation from 40 MHZ to 400 MHz. Available in toroidal cores, > shield beads, multi-aperture cores and special shapes for RFI > suppression. > MATERIAL 73 (µ = 2500) Primarily a ferrite bead material. Has good > attenuation properties from 1 MHZ through 50 MHz. Available in > beads and some broadband multi-aperture cores. 43 is recommended for wideband use from 1 to 30MHz but 73 is recommended from .2 to 15MHz. So on 160m through 20m you could use both and you'd wind fewer turns (for a given reactance). It would seem 43 would be the preferred choice but I suspect both would work with 73 being better at lower frequencies. Or, EMRFD way, you could try both and measure the difference (it's a 50c part).
692	2007-05-02 02:08:59	Giancarlo	Re: Binocular Core Selection For H-Mode Mixer
Hi Jim, thanks for your note. #73-2402 should be good for H-mode mixers to convert from 8 to 10MHz IFs to 455kHz 2nd or 3rd IF. #73 Not a common value this side. 73 Gian I7SWX

In this article?

<http://www.w8ji.com/core_selection.htm>

> I mainly use 73 material for receiving applications in LOW POWER
> applications between .1 and 30 MHz. 73 and similar core materials
> generally minimize the turns count required without inducing
> excessive loss. One of the best indicators of correct core
> selection is looking at the turns required. You'll notice most of
> the transformers I use have only one or two turns for every 100
> ohms of impedance. My 75 to 450 ohm Beverage transformers, for
> example, only require two-turn primary and 5-turn secondary
> windings. A low "turns count" is a good indicator the correct core
> size and core material is being used.

and (remember he's talking about TX baluns here)

> At higher power levels, it is necessary to move to lower loss
> tangent and higher curie temperature materials like 65, 61, or (in
> extreme cases) 43 materials. Even a fraction of a dB loss produces
> significant heating in small cores when power level is in the
> kilowatt range. The loss DIFFERENCE in non-resonant applications
> between lower and high ui ferrite cores isn't significantly
> different, but heating can be much less!

Of course there's

<http://www.amidoncorp.com/aai_multiaperture.htm>
<http://www.amidoncorp.com/aai_ferritecores.htm>

> MATERIAL 43 (µ = 850) High volume resistivity. For medium frequency
> inductors and wideband transformers up to 50 MHz. Optimum frequency
> attenuation from 40 MHZ to 400 MHz. Available in toroidal cores,
> shield beads, multi-aperture cores and special shapes for RFI
> suppression.

> MATERIAL 73 (µ = 2500) Primarily a ferrite bead material. Has good
> attenuation properties from 1 MHZ through 50 MHz. Available in
> beads and some broadband multi-aperture cores.

43 is recommended for wideband use from 1 to 30MHz but 73 is
recommended from .2 to 15MHz. So on 160m through 20m you could use
both and you'd wind fewer turns (for a given reactance).

It would seem 43 would be the preferred choice but I suspect both
would work with 73 being better at lower frequencies.

Or, EMRFD way, you could try both and measure the difference (it's a
50c part).