Page 1 of 1

12V operation querries

PostPosted: Fri Apr 24, 2015 8:39 pm
by Sanath
Hello All,
I just successfully finished testing the RX portion and am about to begin the TX section. Reading many of the earlier posts scattered under various topics, i understand that the peaberry SDR will work on 12v but will NOT put out 1W. So, what is the nominal power expected for 12v operation on 30/20/17/15m bands . Wonder if any one has any quick "MODs" to the PA and TX driver sections for a 1 W operation on 12 V ??. Guess i am stuck with the Watt fever nevertheless am still curious!
Cheers and 73

Re: 12V operation querries

PostPosted: Sat Apr 25, 2015 2:14 am
by pilotcfii
I run my 60/40/30/20 V2 on a 13.8V power supply and can get as much as 2 watts on all bands and 3 watts on one of them. However it's my understanding and belief that much power comes from a non-linear portion of the PA. Therefore I am have reduced the power down to just 900mW. Never fear the low power though. One of my JT65 QSO's was to Austria from Alabama at 900mW. That power setting also helps keep the PA cool.

Perhaps a power supply at 12V will limit you but the Peaberry is quite comfortable at 13.8 and that is the recommended power supply voltage.

Good Luck & 73.

Re: 12V operation querries

PostPosted: Sat Apr 25, 2015 3:27 am
by W4MMP
David recommends 13.8V. It is my understanding that the PA and bias circuits were designed to work the best at the 13.8 voltage level. Then, keep the audio drive down to a level that the Peaberry outputs no more than 1W. This is sweet spot for the Peaberry.

Re: 12V operation querries

PostPosted: Sun Apr 26, 2015 9:11 am
I noticed on the front clear housings it is engraved with a 13.8 vdc just below te power jack.............
I have two running all the time, and they love 13.8vdc.
73Brian wb7qdr,, wb7qdr,wb7qdr/qrp .Check out my contacts on the bands with mostly Peaberrys, I have three new countries this week from 20-50 watts ssb.

Re: 12V operation querries

PostPosted: Wed Jun 17, 2015 2:32 pm
by Sanath
Hello all ,

Thanks to some friendly neighborhood hams my build of the peaberrySDR 30/20/17/15 was tested under both 12 V and 13. 8 V. He was happy to report that the receiver as expected performs extremely well irrespective of the feed V being 12 V or 13. 8 V.

Transmitter is very sensitive to the V specially on higher frequency side as seen from the table below
Under 12/13.8 V operation
30m 1.04 / 1.90 W
20m 0.39 / 0.98 W
17m 0.00 / 0.44 W
15m 0.00 / 0.29 W

Any first glance comments/ suggestions/ sanity checks please ??.
I do want to make ot operational on 12V. Any suggestions will be helpful. I do understand that it was designed for 13. 8 V , but any pointers to make it operational on 12V will be appreciated

Ps have to mention that under 12 V operation and 0.39W on 20M, fed to a resonant feedline dipole flat on roof @ 30ft ,my wspr signal was heard in Europe. Thats over 7000km from my QTH !

Brookings, South Dakota

Re: 12V operation querries

PostPosted: Wed Jun 17, 2015 2:52 pm
by kz1x
The supply voltage is a careful compromise between dissipation of the ballast resistors before the regulators and the supply voltage to the power amplifier stage (primarily Q7, 8 & 9).

Re: 12V operation querries

PostPosted: Wed Jun 17, 2015 10:12 pm
by N2TOH
What about LiPo cell operation?