[hpsdr] Pennywhistle bias

[Graham / KE9H]

John:

I think things are normal.

You will also discover that the no-signal bias levels for the transistors
will walk around 50 to 100 mA with heat sink temperature, so getting within
10 mA at room temperature is just fine.

Time to send some RF through the PennyWhistle.

--- Graham / KE9H

==

On Fri, Dec 25, 2015 at 9:44 AM, John Ackermann N8UR <jra at febo.com> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
> First of all, happy holidays!
>
> I'm finally getting around to building up a Pennywhistle to add to my
> Atlas-based system.
>
> When I do the bias set procedure, with both pots fully CCW I'm seeing
> about 8mA current draw, instead of the 20mA referenced in the doc.  I can
> set the bias for each transistor to 450mA, but the setting is very touchy
> and it's hard to set closer than within 10mA or so of the target.
>
> Does this seem normal, or should I be looking for a problem?  I haven't
> tried applying RF yet...
>
> Thanks,
> John
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at openhpsdr.org
> Subscription help:
> http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
> HPSDR web page: http://openhpsdr.org
> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/attachments/20151225/123e2b63/attachment.htm>