Topics

U3S with added BS170's still on 5V.

N3MNT
 

More out of curiosity than anything else, has anyone added the 2 additional BS170's to the U3S and run on 5V.  Did it change power much?  Hans says slight increase.  I want to keep the unit as portable as possible and operating on 5V only accomplishes that.  I also want to stay with the spirit of Weak Signal operation.  Initial operation on 20M yielded a 5700 mile catch.  All the QRP-Lab kits I have built have performed above expectations.

M0RON
 

My u3s has 3 bs170's at 5v, I have no problem getting to Tasmania or South Pole with it. 
Power out is around 1w on 7mhz, running at lower voltage and bias only just increasing current has resulted in the pa transistors being much more reliable, I use 13.8v input to a 7805 with caps on input and output. Incidentally I use 3 7805's, 1 for logic, 1 for heater and 1 for pa. 
i also have a Rfzero running at 5v and 0.02w output, works well and no drift. 
Andy
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.