[ARC5] BC-455 IFT - measurements

[Dennis Monticelli]

If the two coils were tightly coupled then one could "compensate" for a few
extra pF on one side by tuning the other side's trimmer a little lower in
value than it would otherwise require for resonance.

But it's probably moot anyway because the coupling is loose.

Dennis AE6C

On Wed, Oct 29, 2014 at 12:43 PM, Mike Feher <n4fs at eozinc.com> wrote:

> I agree, it is pretty loose. Regardless, if the secondary resonates with
> the
> 12SK7 interelctrode capacitance, plus a few stray pfs here and there, it
> would be about 1 MHz. I have not measured the self-resonance, which may be
> even lower. So, it is really just acting as a high impedance broadband
> input
> to the grid. 73 - Mike
>
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell, NJ, 07731
> 732-886-5960
>
>
> -----Original Message-----
> From: ARC5 [mailto:arc5-bounces at mailman.qth.net] On Behalf Of
> kgordon2006 at frontier.com
> Sent: Wednesday, October 29, 2014 3:28 PM
> To: Dennis Monticelli
> Cc: ARC5 at mailman.qth.net
> Subject: Re: [ARC5] BC-455 IFT - measurements
>
> On 29 Oct 2014 at 10:58, Dennis Monticelli wrote:
>
> > Perhaps someone can comment upon the degree of coupling between the
> > two coils.  If the coupling is tight, then the capacitance's on both
> > sides will interact.  Adjusting one side will pull the other side into
> > pretty much a single resonant circuit.  Perhaps that was what was
> intended.
>
> Dennis:
>
> In my opinion, the coupling is pretty loose, but I have no way to quantify
> that at this point.
>
> What I will do is to take a close-up photo of my 7277 IFT with the cover
> removed, and with a tape-measure along side of it so you can see the
> distance between and the orientation of the two coils.
>
> Then if you would give us your opinion of the coupling, I would be
> grateful.
>
> vy 73,
>
> Ken W7EKB
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>