Fifth Launch s’more-005

u4b

WSPR

20m

3rd tele

32in balloon x2

Helium 99%

Goal was higher altitude by pumping out balloons before fill with helium. Used “Party Factory” helium.

Implemented 3rd telemetry packet.

Problems: very strong transmission seen, but never decoded. After launch no spots were returned.

Published

May 25, 2026

Abstract

Smore-005 was similar to smore-003, with a goal of acheiving higher altitude. The balloons were pumped out with the pump in reverse to evacuate any air before filling with Helium. The launch went well, the balloon rose, but no telemetry was received. We heard confimation on the ground of transmit tones, but WSJT-X was not working properly to look for decodes.

Pictures

Tracking information

Figure 1: WSPR Telemetry Viewer embedded tracker

WSPR Telemetry Viewer tracking link

Pre-launch design and preparations

u4b tracker
- u4b-006
zener diode regulation
supercaps x2
HF antenna - 20m band
GPS antenna
2 balloons
- stretch
- leak test
- suck out air
WSPR channel selection

Balloon filling calculations

See Balloon filling calculations for earlier flight

Launch checklist

Pre-launch

check forecast for wind and clouds
fill balloons

At launch site

verify wind and clouds OK
check payload voltage in sun
check WSPR transmissions on ground with SDR Rx

Payload design

New payload design with 3 solar panels and zener diode.

U4B and programming information

Configuration

Firmware: 1.01.004 (upgraded 23 May 2026)
Callsign: KF8EEZ
Band: 20m
Channel: 370
- 8 minutes after, 14,097,180 MHz
Autostart: TRACKER2
QRP-labs S/N: 969

Background info

QRP-labs u4b info page: https://qrp-labs.com/u4b
Traquito channel reservation: https://traquito.github.io/channelmap/

README

Edited README on u4b to contain contact and WSPRtv tracking information in the unlikely event that someone can find it.

Note

IF YOU ARE READING THIS:

BALLOON OPERATED UNDER CALLSIGN KF8EEZ. LAUNCHED FROM DAYTON, OHIO, USA.

TRACKING: HTTPS://WSPRTV.COM/?CS=KF8EEZ&CH=370&BAND=20M

EMAIL: PHONE:

GPS antenna

half wavelength: 95.14683639918243 millimeters quarter wavelength: 47.57341819959122 millimeters quarter wavelength * 95%: 45.194747289611655 mm feed length: 25.400000000000002 mm total length: 70.59474728961166 mm

HF antenna

top and bottom arms from U4B about 5 inches. Antenna arms should be about 198.84837766362426 inches. I created two spools of 200 inch long each. For both, need to cut about 6.16 inches off of the spooled wire.

Upper

Code

print(200 + 5 - 198.84)

6.159999999999997

= 6.16 in

Lower

Code

print(200 + 5 - 198.84)

6.159999999999997

= 6.16 in

GPS antenna

Twisted pair feed, 50mm arms. Tested. Good GPS fixes.

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
X is the ERLON - Easting value
Y is the ERLON - Northing value
Z is the “big number” for telemetry

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.

This code should be edited for each flight. Specifically, set: - channel number: CH=xxx - test mode: T=1 for test without GPS/Telemetry OR T=0 for live

PRINT "INIT START"
LET CH = 370
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 "*** TEST MODE ***"
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) This packs additional telemetry into the Z variable and sends a 3rd telemetry packet.

THESE URLs create the telemetry packet decode for WSPRtv.com: https://wsprtv.com/?cs=KF8EEZ&ch=216&band=20m&start_date=2026-05-17&ct_dec=ct,s:2_500:0:1,2:0:1,38:0:1,1000:t100,1000:t101&ct_labels=count,power,nsat&ct_llabels=spot+xmit+since+power,power,number+sats

https://wsprtv.com/tools/ct_wizard.html?spec=https%3A%2F%2Fwsprtv.com%3Fcs%3DKF8EEZ%26ch%3D216%26band%3D20m%26start_date%3D2026-05-17%26ct_dec%3Dct%2Cs%3A2_500%3A0%3A1%2C2%3A0%3A1%2C38%3A0%3A1%2C1000%3At100%2C1000%3At101%26ct_labels%3Dcount%2Cpower%2Cnsat%26ct_llabels%3Dspot%2Bxmit%2Bsince%2Bpower%2Cpower%2Cnumber%2Bsats

PRINT "TELEMETRY START"
RUN "LEDOFF"
LET Y = ERLAT 1000
LET X = ERLON 1000
LET Z = 0
LET Z = PACK Z 1000 Y
LET Z = PACK Z 1000 X
LET Z = PACK Z 38 SC
LET Z = PACK Z 2 HP
LET Z = PACK Z 500 C
IF T = 0
PRINT "REAL TELE"
TELE
TELEC Z
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

BLINK

turns led on and off B times. you must set b first

FOR L = 0 TO B
RUN "LEDON"
DELAY 100
RUN "LEDOFF"
DELAY 100
NEXT