Automatic regulator 4S Lipo on Mt. Esparatz EA2/NV-095

Hello SOTA mates!

The homebrew device:
Some time ago I tested together with Jorge, EA2LU, a voltage reducer for his 4S cell LiPo battery, used to protect the rig from the excessive voltage (16,8 V) when the battery is fully charged.
He reduced the voltage by adding some Diodes in series between the battery and the transceiver. You can see details here:
Manual 4S regulator

The idea works well but nevertheless, it’s not the optimal solution as you have to monitor batt voltage to be aware for when it’s necessary to bypass the diodes once the voltage is safe.

Jorge decided to build an automatic voltage reducer following the schematic prepared by AD5X whose details you can read on Internet (here).

Jorge brought his kit today for the activation of Mt. Esparatz. The device worked fine and the supplied voltage to the KX-3 rig was all time a constant 13,5 V level, operating at 10 w power out.

See Jorge comfortably operating this morning with his device plugged next the rig with its bright red led indicating operation:

Mt. Esparatz, driving directions:

  • Exit Pamplona towards Orcoyen (road PA-30)
  • Keep straigh towards Arazuri - Ororbia - Ibero - Etxauri (road NA-700)
  • Pass Etxauri and take deviation towards Ciriza (road NA-7110).
  • Pass Belascoain and take the deviation towards Arguiñariz (road NV-7111)
  • Park at the entrance of Arguiñariz and start the climb.

(I will upload GPS track in the SOTA Mapping web page).


  • Trail is 2,4 kilometer long (one way)
  • Heigh gain: 310 m.

This is an easy trail that starts by passing by the door of the church in Arguiñariz. Pay attention when you reach the water reservoir up the village as you need to abandon the wide dirt road to the left hand side to follow a smaller and steeper path.

Anyway the route is clear and progressive being confusing only next the summit when you have several paths crossing and you must be careful.

The path passes a pine tree forest:

The summit is a wide area over the trees with good views in all directions. It’s easy to distinguish several SOTA summits next our position. See the view heading South this morning with several summits shown in the picture:

Weather was good, forecast was cloudy and 14 C but we were lucky and had no wind during the activation.


  • Date, Saturday 16th September 2017.
  • EA2LU’s station: KX3 @10 watt. multiband EFHW with traps for auto band change.
  • EA2BD’s station: FT-817 @5 watt. EFHW.

We separated well our antennas (about 30m) on the summit to allow simultaneous operation. It worked well and could activate without disturbing between us.

Aerials on the summit (from EA2BD’s position. Notice EA2LU antenna on the background):

EA2LU operating under the very trig point:

As for the usual split between us, Jorge worked CW on 7-10-14 MHz and I gave a run on 14 MHz SSB. My feeling was consistent signals on RX but few chasers this morning. I had some troubles on my frequency when some ham started tuning for ling time on my QRG and I had to QSY up.

My signal reports ranged 53 to 59 and I logged one S2S on SSB (Thanks Paul DL6FBK/P).

When I had no more calls I sat next to Jorge to enjoy listening his chasers. He had a longer log counting around 30 chasers.
I take the keyer a bit and called for a CW S2S (thanks Kurt HB9AFI/P, so strong today!) and got a request for going up afterwards where I logged Roy G4SSH, always a pleasure to meet.

We saw the weather was changing colder and decided to end our activation.
I walked back to my station where I found this unexpected chaser over my log:

We had enjoyed the activation and the nice chat during our walk up and down.
It is so nice to go to the wild and have a break to enjoy from the mental and spiritual benefits that nature provides us. And so good to share that with you all, our ham friends though the waves…

Autumn plants:
During our ascent we passed next a couple of plants that produces some good fruits. These fruits are clear indicators we are exiting from summer as it is popular to collect them in early autumn.

Blackberries start changing into black color now. Soon we shall see families going to countryside to pick them and enjoy:

We saw some plants of sloe (endrina in spanish, Prunus spinosa tec name), that are ready to pick. In the basque country people collect this fruit and make a well known liqueur called Patxaran.

If you want to make Patxaran you need to soak these sloe fruits together with a few coffee beans in anisette during some months and then removed. Patxaran is a light red color flavoured liqueur with about 30% content in alcohol. It is delightful but to be taken only after a good SOTA activation!

Small quantities served chilly recommended:

VY 73 de Ignacio


Looks like a very nice early autumn activation! Thanks for the QSO and this report. I also heard Jorge on 30m at the same time, good copy about 549, then I called him, and immediately his signal was all but gone with the QSB, and I was not sure if he had come back to me. The bands…

vy 73 de Manuel HB9DQM

PS: I would love to try some Patxaran now :yum: :wink:

1 Like

Hi Manuel,
thanks! Your signal was excellent at my end.
I was glad when I recognised your call and I immediately recalled your recent activation in Gumihorn.

I will be pleased if you spend some days and activate in EA2… Patxaran would be in the schedule for sure :innocent:
VY 73 de Ignacio