Re: Hyper-Cricket at 12 volts?2


Jim Sheldon
 

I tested that yesterday on mine.  The answer is everything in the RX works fine on 12 volts.  The transmitter is a different story.  The PA transistor, Q2, heats up very rapidly and I don't think it will last through a normal QSO.  The power output does not increase by enough to make any real difference so the overall answer is NO it ain't gonna work on 12 volts.  After sending CQ CQ CQ de W0EB W0EB W0EB K once using 12 volts, Q2 was so hot it would blister your finger if you weren't careful touching it.  Voltage per power out with a 2N7000 at Q2 - 9.5 volts, .75 watts, 10 volts .80 watts, 11 volts .89 watts and at 12 volts it was .9 to 1.0 watts out.  Swapped Q2 to a BS170 and got identical results (less than .02 watt difference) so there is really nothing to be gained by running the Cricket on 12 volts except de-soldering/soldering practice when replacing Q2 every time it failed.

Jim, W0EB

------ Original Message ------
From: "Kenneth Ketner klaine@... [4sqrp]" <4sqrp@...>
Sent: 5/3/2017 10:41:54 PM
Subject: [4sqrp] Hyper-Cricket at 12 volts?

Will the little chirper take 12 volts for a bit more output? 

I recently saw a circuit, Tayloe simple tx at Hendricks kits, that got 4 watts on 3 parallel bs170 s.

Ken Ketner
KA5ELD
PO Box 65135
Lubbock, TX 79464-5135
Sent from my iPad

Join main@4SQRP.groups.io to automatically receive all group messages.