[ARC5] JFET in ARC-5 TX oscillator socket

[Dennis Monticelli]

Drive will obviously be an issue with a 12V powered lightweight JFET like
the ones mentioned.

However, power could be boosted by cascoding the JFET with either a 300V
bipolar or MOSFET.  Just bias the cascode device with a couple of resistors
and a bypass cap so that a clean voltage under 20V is applied to the JFET
when normal B+ is applied to the whole circuit.  Under these conditions, a
JFET with a little more punch (like the J113 or MPF820 or 2N5639) should
produce a healthy output.  Because the oscillating JFET stays cool and only
the cascode device gets warm, drift should be good.

Dennis AE6C

On Fri, Jul 3, 2009 at 5:14 PM, Kenneth G. Gordon
<kgordon2006 at verizon.net>wrote:

> On 3 Jul 2009 at 15:46, Ian Wilson wrote:
>
> > Removed all the tubes, plugged in 1626 socket. Applied 12V to pin 3
> > (bypassed to ground) and ground. Result is a rock-solid signal (hasn't
> > shifted anything like 10Hz in 10 minutes (!)).
>
> Ian:
>
> What is the P-P RF voltage output?
>
> 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
>