Second Launch s’more-002

Published

November 6, 2025

Tracking information

Weather information

this shows weather along the predicted HYSPLIT path (Section 3).

Clouds for 2025-11-14

All earlier weather

Track predictions

Forward predictions for 2025-11-14

There are no spots today, but yesterdays prediction had the ballloon too far north for the sun to activate it.

Prediction from 2025-11-13 at 2025-11-14 1000Z

Prediction from 2025-11-13 at 2025-11-14 1000Z

Doing a new prediction using these starting lat/long points 1025, 40.5880, 50.9080, 254. 2025, 42.7470, 52.6150, 227. 3025, 44.4120, 52.2830, 240.

Prediction from 52.615N/42.747E at 6440 meters

Ensemble predictions starting from 52.615N/42.747E at 6440 meters

Ensemble predictions starting from 52.615N/42.747E at 6440 meters

All earlier predictions

Payload weight

  • USB connector removed from U4B.
  • With antenna winders: 31.7 gram.
  • Antenna winder 1: 7.6 gram
  • Antenna winder 2: 7.4 gram
  • Total antenna winder: 15 gram
  • Payload weight: 16.7 gram

Balloon filling calculations

See Balloon filling calculations

Launch 2025-11-06

Tracking link: https://wsprtv.com/?cs=kf8eez&ch=109&band=20m&start_date=2025-11-06&sun_el=25

Field before launch

Clear, no wind, but geese. The geese were not a problem and just got out of the way.

Field as seen when we arrived, lots of Canadian geese

Field as seen when we arrived, lots of Canadian geese

Payload setup

Launch set up without balloon

Launch set up without balloon

Balloons set up with payload

Balloons set up with payload

Measuring solar panel voltage

Ground WSPR monitor

I’m using a LimeSDR and homebrew mag antenna to monitor for transmissions at the launch site.

Mag antenna setup

Mag antenna setup

Laptop SDR detect

Laptop SDR detect

Payload at launch

Payload held just before release

Payload held just before release

Launch

Balloon aloft

Balloon aloft

Attempts

Attempted Launch 2025-10-04

Attempt1: Bad balloons, geese and clouds

Attempt1: Bad balloons, geese and clouds

Scene of launch field looking south

Scene of launch field looking south

Payload waiting for launch

Payload waiting for launch

Attempted a launch but failed for two primary reasons:

  • payload failed to power up and transmit at launch site
  • one balloon lost about 75% of it’s gas can could not provide lift

Subsequent testing of the payload shows that it’s working fine, and transmitting OK. Currently hung up on test system in yard. See WSPRtv

The weather high clouds and the attempted launch was early. I suspect that the solar intensity was too low to power the transmitter.

Also learned of a new risk: Canadian geese on the field.

Remember to pack:

  • yellow measuring tape to mark out antenna location (good visual indicator)
  • battery to power payload if sun is not strong enough
  • volt meter to test solar panel and payload voltages
  • SDR and HF antenna to listen for transmission

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

S’more 002 payload design

U4B and programming information

qrp-labs S/N: 21894

Hardware

Part | no | weight |
Powerfilm MPT48-150 | 1 | 3.8 |
supercap AVX_SCC_3_0V-2952762 | 2 | 2.4 |
volt regulator L7805CV | 1 | 1.7 |
u4b | 1 | 5.4 |
upper HF antenna + rigging | 1 | 4.1 |
lower HF antenna | 1 | 0.9 |
TOTAL | | 18.2 |

Configuration

  • Callsign: KF8EEZ
  • Band: 20m
  • Channel: 109
  • Autostart: TRACKER2

Programs

Tracker 2

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"
PRINT "INITIAL GPS"
RUN "MYGPS"
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

  • 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
PRINT "INIT START"
LET CH = 109
LET HP = 0
LET C = 0
LET N = 2
LET T = 0
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"

LED off

OUT 19 1

LED on

OUT 19 0

Ground testing telemetry

One set of telemetry from ground testing

251016 1736  35  0.32  14.0970715  KF8EEZ EM79 10          0  0.80  1  1    0  0   0     1   810
251016 1736 -28  0.37  14.0971916  KF8EEZ EM79 10          0  0.47  1  1   56  1  34     1   810
251016 1738  10  0.24  14.0970673  0X5DBN OI57 53          0  0.12  3  1   -8  1  31     1   810
251016 1738  34  0.32  14.0970714  0X5DBN OI57 53          0  0.76  1  1    0  0   0     1   808
251016 1738 -20  0.49  14.0971915  0X5DBN OI57 53          0  0.19  3  1    0  0  13     1   429