Fourth Launch s’more-003

Published

May 3, 2026

Abstract

The new 3 solar panel design was meant to allow operation at lower sun elevations and suceeded allowing operation down to nearly 10 degrees solar elevation. The voltage regulator was replaced with a zener diode which reduced the weight of the payload.

Tracking information

Payload at launch

Smore-003 3-solar panel payload waiting for launch

Smore-003 3-solar panel payload waiting for launch

Smore-003 additional view

Smore-003 additional view

Pre-launch design and preparations

  • u4b tracker
  • zener diode regulation
  • supercaps x2
  • 3 half solar panels
    • schottkey diodes
  • HF antenna - 20m band
  • GPS antenna
  • 2 balloons
  • WSPR channel selection
    • planning channel 567, 2 minutes after, 14,097,060 MHz
    • registered in QRP-labs database as smore-003 [2026-02-08]
    • tried to register in traquito system, but doesn’t work [2026-02-08]

Payload weight

  • USB connector removed from U4B.
  • With antenna winders: 31.7 gram.
  • Antenna winder 1 (bottom): 6.2 gram
  • Bottom antenna + winder: 8.5 g (200 inches wire)
  • Antenna winder 2 (top): 6.2 gram
  • Bottom antenna + winder: 10 gram (200 inches wire + fish line)
  • Total antenna winder: 15 gram
  • Payload weight: 16.7 gram

Balloon filling calculations

See Balloon filling calculations for earlier flight

Launch checklist

Pre-launch

At launch site

Testing

2025-10-16

Set up balloon payload on wooden poles with horizontal wiring in morning of 2025-10-16 and let it start with sunrise.

wspr.rocks spots

Downloaded spot from https://wspr.rocks in both json and tsv format for comparison.

These are the spots from one day of testing 2025-10-16 local time 2025-10-16-wpsr-rocks-spots.json 2025-10-16-wpsr-rocks-spots.tsv

lu7aa spots

https://lu7aa.org.ar/wsprx.asp?banda=All&other=KF8EEZ&balloonid=&timeslot=&SSID=&launch=&tracker=qrplabs

csv file created by copy/paste from website

2025-10-16-lu7aa-spots.csv

this shows decoded telemetry also https://lu7aa.org/wsprx.asp?banda=20m&other=kf8eez&balloonid=05&timeslot=8&repito=on&qrpid=109&SSID=11&launch=20251016010101&tracker=qrplabs

wsprtv.com

shows charts https://wsprtv.com/?cs=kf8eez&ch=109&band=20m&start_date=2025-09-17

downloaded csv to KF8EEZ_109_20250917-20251017.cs

power down

Solar panel ends in shadow early due to trees.

Let up over night to allow to start again with sunrise.

2025-10-17

Came back up after overnight testing and starting transmitting. Brought inside due to forecast rain overnight.

2025-10-20

Additonal testing. Working in sun.

2025-10-23

Broke off the USB connector from the U4B and mounted again outside for testing. Partly cloudy but transmitted fine during sun.

Payload design

New payload design with 3 solar panels and zener diode.

U4B and programming information

Configuration

  • Firmware: 1.00.005 (make sure to upgrade to this version)

  • Callsign: KF8EEZ

  • Band: 20m

  • Channel: 567

    • 2 minutes after, 14,097,060 MHz

  • Autostart: TRACKER2

  • QRP-labs S/N: 21811

  • zener diode as regulator, 3 1/2 panels to provide voltage

  • mass: 16.9 gram including u4b-usb connector.

HF antenna

for top antenna leg, attached wire to fishing line with kapton tape, small piece about every 12 - 18 inches apart. Cut off small folded over ends with sticky tab.

Programs

Variables

  • C is the count of transmissions since wake up
  • N is the number of transmissions before switching to high-power (0-based)
  • T is a flag for test mode
    • T=1 - test mode
    • T=0 - live mode - must be in live mode for flight
  • B is the number of times to blink the led, set to 5

TRACKER2

This is the primary program. The MYTELE and MYGPS subroutines enable control of a test mode which doesn’t need GPS or ability to transmit.

PRINT "START TRACKER2"
RUN "INIT"
RUN "SHOW"
LET B = 5
RUN "BLINK"
PRINT "INITIAL GPS"
RUN "MYGPS"
LET B = 2
RUN "BLINK"
10 PRINT "LOOP AT #VC"
RUN "SHOW"
RUN "MYTELE"
LET C = C + 1
IF C > N
    LET HP = 1
ENDIF
RUN "MYGPS"
GOTO 10

INIT

Initialization should run once on power up.

PRINT "INIT START"
LET CH = 567
LET HP = 0
LET C = 0
LET N = 2
LET T = 1
LET B = 5
PRINT "HOST USB:    #US"
PRINT "HIGH POWER:  #HP"
PRINT "FREQUENCY:   #FQ"
PRINT "CHANNEL:     #CH"
PRINT "CALLSIGN:    #CS"
PRINT "TEMPERATURE: #TK"
IF T = 1
PRINT "FAKE GPS/TELE MODE"
ELSE
PRINT "REAL GPS/TELE MODE"
ENDIF
PRINT "INIT DONE"

SHOW

Prints out the current state

PRINT "SHOW START"
PRINT "LLH:  #LT #LN #AT"
PRINT "GPS:  VALID: #GV LOCK: #GL SPEED: #GS CALIB: #CL"
PRINT "GPS:  NSAT:  #SC"
PRINT "CNT:  #VC"
PRINT "TEMP: #TK"
PRINT "POWR: #HP"
PRINT "SHOW DONE"

MYGPS

This is my GPS program, it lets you use the GPS in a test mode without an actual signal. Don’t acquire GPS if in test mode (T=1)

PRINT "GPS START"
RUN "LEDOFF"
IF T = 0
PRINT "REAL GPS"
GPS 360
ELSE
PRINT "FAKE GPS"
DELAY 2000
ENDIF
RUN "LEDON"
PRINT "GPS END"

MYTELE

Don’t transmit if in test mode (T=1)

PRINT "TELEMETRY START"
RUN "LEDOFF"
IF T = 0
PRINT "REAL TELE"
TELE
ELSE
PRINT "FAKE TELE"
DELAY 2000
ENDIF
RUN "LEDON"
PRINT "TELEMETRY END"

LEDOFF

Turn LED off

OUT 19 0

LEDON

Turn LED on

OUT 19 1