JA6YBR/b in Miyazaki, JAPAN
operating on 50.017MHz

Presented by Shirow KINOSHITA;JF6DEA/KE1EO
and JA6YBR operating team

Updated in July 2021

JA6YBR in Miyazaki city (South western part of Japan) started her operation in 1985 as 50MHz beacon and has been operating continuously until now. We introduce outline, history and some record of JA6YBR on this page.


1. Callsign JA6YBR

2. Frequency 50.017MHz

3. Mode CW (A1/A1A)

4. Operating Time 24 Hours (Basically)

5. Location MIYAZAKI; South Western part of Japan
Long: 131 25' 38" E
Lat : 31 49' 11" N

6. Grid Locator PM51rt

7. Transmitter/Power Homebrew a pair of 2SK410s (50W max)

8. Antenna
Turn Styled Hentenna
/60m ASL/15m Above the ground
/Omni Direction

9. Transmitting
PM51RT *- **- ***- ****-
Rmks: "VVV" to "*-": 50W

10. Operating Manager Shirow KINOSHITA; JF6DEA/KE1EO

11. Reporting Address Shirow KINOSHITA; JF6DEA/KE1EO
E-mail: bcon(at)ja6ybr.org




* Concept installation of 50MHz Beacon at Miyazaki in 1983 to mid of 1985
At the time, it was not easy to study 50MHz propagation from/to Kyushu (JA6) area, because there was a only 50MHz beacon; JA2IGY (on 50.010MHz), located at central Japan. Therefore, they proposed 50MHz beacon installations in Miyazaki, where was not so high amateur radio activity on 50MHz.

* Nov.3, 1985 : Launching operation of JA6YBR Beacon
It started the beacon operation of JA6YBR at Miyazaki Univ. in Kirishima, Miyazaki city. (close to downtown)
  • Frequency : 50.020MHz,
  • RF Output Power : 10W,
  • Antenna : Stacked squalo (20/17m A.G.L) as horizontal omni directional & polarization.
All equipment was designed and assembled by Take:JH6AVS. The RF final device of the transmission equipment was a 2SC2395. At the time, transmission message was gVVV DE JA6YBR JA6YBR 4501 VVVh

* Jul.25, 1986 : Beacon operation was suspended
Beacon operation was suspended because of relocation of Miyazaki Univ. from the city to suburb area.

* Sep.15, 1986 : Change callsign to JF6DEA/6 and the beacon restarted
All equipment was relocated to Hongo-Minami kata, Miyazaki city (PM51ru) and the callsign was changed to JF6DEA/6. Then the beacon was restarted. Transmission message was change to gVVV DE JF6DEA/6 4501 PM51RUh.

* Sep.23, 1987 : Change callsign to JE6ZIH
* Oct.16, 1987 : Beacon operation was suspended for QSY
* Nov.13, 1988 : Change frequency to 50.017MHz
The beacon operation was restarted. With upswing of the propagation condition on Cycle 22, operating frequency was changed to 50.017MHz considering QRM with GB3SIX on 50.020MHz.

Since this time, with a goal of renewal of the equipment, it started discussion among Take:JH6AVS, Han:JE1BMJ and Shirow:JF6DEA using Packet Radio Network. And it made a start on design and assembles of the new equipment of the beacon to install in May 1989.

* May.3, 1989 : Callsign was back to JA6YBR and all equipment replaced
The beacon was back to Miyazaki Univ. at Kibana-dai, Miyazaki city, (PM51rt) after completion of the university relocation. Callsign was back to JA6YBR. All equipment was replaced to new intelligent system with Z-80 CPU and a pair of 2SC2290s, which is designed and assembled by Take:JH6AVS and Han:JE1BMJ. Transmission power level was changeable with 50/10/1/0.1W. Antenna system was turn styled dipole, which is 15m above the ground and omni directional & horizontal polarization as before.

* May.3, 1990 : Change antenna to turn styled hentenna
To reduce wind area, the antenna system was changed to turn styled Hentenna, which was fabricated by Take:JH6AVS. Antenna height was 15m A.G.L as before. (Around Miyazaki area, it has been coming typhoons more than a couple of times in a year.)

* Sep.6, 1993 : A major typhoon made the beacon operation suspend
The beacon was suspended because a major typhoon destroyed antenna system.

* Sep.23, 1993 : Restart operation using temporary dipole antenna
* Nov.6, 1993 : Change antenna to new turn styled hentenna
The new wind-resistant Hentenna, which was fabricated by Masa: JI6KGZ was installed. And the CPU buck-up battery, produced and donated by Nori:JH6EBR was added to the equipment.

* Aug.22-23, 2009 : Exbition at Ham Fair 2009 in Tokyo
After 24 years since beginning of operartion, JA6YBR/b was exhibited at the "HAM FAIR 2009" in Tokyo. More than 100 people visited the booth of JA6YBR/b.

* Feb.6-7, 2010 : Maintenance of equipment
It is the first maintenance since replaced equipment has been installed in 1989. The coaxial cable was changed and the equipment was cleaned out. Due to implication of some trouble at the attenuator for power control, it has not been transmitted the signal of 1W & 0.1W, tentatively.

* Mar.9, 2012 : Temporary sign-off for maintenance
At 09:45z on Mar.9, 2012, JA6YBR/b was temporarily signing-off, because of equipment maintenance.

* Apr.12, 2012 : Back to service after maintenance
At 04:50z on Apr.12, 2012, JA6YBR/b has been back to service after installation of new transmission equipment (the third generation).

***** PHOTO GALLERY *****

* Transmission Equipment (The third generation, since April 12, 2012)
New transmission equipment is enclosed in old-fashioned TS-520X HF tranciever's chassis. Home brew system designed and assembled by Take:JH6AVS and Han:JE1BMJ. This equipment is equipped with PSU and the final unit composed of a pair of power MOS-FETs.

* Block Diagram
Oscllation unit of Type POCO, which is extremely stable with less than +/-0.1ppm at -30 to 60 deg. celsius, to the driver of a 2SK409 through some buffers, and the 2SK410x2 final RF Amplifier. CPU unit controls RF power output (50/10/1/0.1W) by Pin-type ATT. The protection unit, which detects over current of 2SK410's drain and RF reflection power, is added this time.

* Control Unit
The control unit is divert from the second generation transmission equipment. This unit is equipped with Z-80 CPU, which controls 4-level RF power, senses the voltage (Vd) and current (Id) of final device, designed and assembled by Han:JE1BMJ. The 6-digits display (center, vertical) has been shown the transmitting message time to time.

* Inside of Equipment
This time, it is again the professional design work of final unit assembled by Take:JH6AVS. This final unit is powered by a pair of power MOS-FETs design, composed of two-2SK410s and capability of enough 50W continious and stable RF output!

* Antenna
The antenna system is "Turn-Styled Hentenna", which is assembled by Masa: JI6KGZ and originally designed by JH1FCZ. The mast and horizontal element are memento of JA5GJN (SK). The antenna is located at the top of 3 stories building, about 15m above the ground. This antenna makes omni directional and horizontal polarized radiation. You can get further information in "The ARRL Antenna Compendium vol.5" introduced by Shirow; JF6DEA/KE1EO.

***** ANOTHER PIX *****

* Transmission Equipment (The second generation)
---[Since May 3, 1989 to March 9, 2012]
Home brew system (The alminum case at right and the back of the VSWR meter) designed and assembled by Take:JH6AVS and Han:JE1BMJ. This equipment is with intelligent CPU, which controls 4 level variable power; 50/10/1/0.1W since 1989. Another aluminum case on the top of the power supply is the back-up battery for CPU, which is design and donated by Nori:JH6EBR.

* Block Diagram
Oscllation unit of Type POCO, which is extremely stable with less than +/-0.1ppm at -30 to 60 deg. celsius, to 2SC2395x2 driver through some buffers, and the 2SC2290x2 (push-pull design) final RF Amplifier. CPU unit controls RF power (50/10/1/0.1W) by ATT through switching unit.

* Inside of Equipment
From down to up, the Control Unit, the Oscillator to the ATT Unit and the RF Driver to the Final Unit.
Professional design work of final unit assembled by Take:JH6AVS. This final unit is powered by push-pull design, composed of two-2SC2290s and capability of enough 50W continious RF output!

* Exbition at Ham Fair 2009 in Tokyo
In August 2009, JA6YBR/b was exhibited at the "HAM FAIR 2009" in Tokyo after 24 years since the beacon was started to operation. Outline, equipment, history and past record were introduced. More than 100 people visited the booth of JA6YBR/b.

* Transmission equipment in 1986
The old transmission equipment (the aluminum case at the bottom left), which was designed and assembled by Take:JH6AVS. The final unit was consist of a 2SC2395 and rated RF output was 10W. This equipment was not enough stability of frequency and output power. The RJX-610 (the 50MHz CW/SSB tranciever in mid 80's in JA) was the monitor receiver of the beacon. The blue key-board was the memory keyer manufactured by 8GEM, which power source was 100V AC. At the time, transmission messege was "VVV de JA6YBR JA6YBR 4501 K". This keyer had no resume function, so ramdom message was transmitted after restoration of every electric power outage.

* Antenna system in 1986
The antenna system in 1986, which is consisted by stacked squalos on the top of 4-stories building at Miyazaki Univ. at Kirishima, downtown Miyazaki city. The beacon was planned as omni directional & horizontal polarization antenna system, therefore this antenna system was employed.

***** PAST RECORD *****

* Utilization case
@At first, the purpose of the Bcon operation was propagation study for ham radio's 50MHz band. More than 20 years later, the Bcon has been used as verious purpose.
  • Detection of abnormal propagation (Sporadic-E including SSSP, Meteor Scattering, F2 propagation, etc.j
  • Evaluation of propagation condition (Ground wave, Mountain diffraction, etc.j
  • Evaluation of operating site in portable operation
  • Performance evaluation of receiving system including antennas and receivers
  • Observation of meteor (HRO:Ham Radio Observation station)
  • Study of earthquake prediction, etc.

* Introduction record
  • "VHF" column on US-CQ (pp.98, August 1988)
  • "The World Above 50MHz" in QST (pp.99, July 1995)
  • Mobile Ham -Magazine in Japanese- (pp.96`97, December 1989)
  • CQ ham radio -Magazine in Japanese- (pp.183, May 1999)
  • ARRL Antenna Compendium Vol.5 (1996), etc.

* Example of receiving record (Snippet by DX Summit, DX SCAPE clusters)
Continent Reporter Receiving
Europe OH6WW Finland Jun.28, 1994 23:56 Multi-hop of sporadic-E?
IK8DYD Italy Jul.9, 2018 06:43 Multi-hop of sporadic-E
W7/VE7CDX Nevada Aug.15, 2009 00:06 Multi-hop of sporadic-E
K0HA Neblaska Jul.31, 2008 22:31 Multi-hop of sporadic-E
NL7Z Alaska Jun.6, 2006 05:19 Multi-hop of sporadic-E
KE7NS Utah Jan.2, 2002 23:37 Multi-hop of sporadic-E?
CE3SAD Chile Oct.9, 2002 02:16 F2 propagation
PY2XB Brazil Mar.27, 2002 03:16 F2 propagation
LU5FF Argentina Mar.16, 2014 03:25 F2 propagation
Africa JH8PHT/CN Morocco Mar.4, 1994 00:30 Long-path of F2 propagation

ASIA: Some reports have been coming from China(BY), Taiwan(BV), Hongkong(VR2), Asiatic Russia(UA0), Korea(HL), Cambodia(XU), Myanmar(XY), West Malaysia(9M2) and Vietnam(3W).
OCEANIA Some reports have been coming from Hawaii(KH6), Guam(KH2), Philippines(DU), Indonesia(YB), Australia(VK), New Zealand(ZL), East Malaysia(9M6), Cook Islands(E5), Christmas Island(VK9X) and Tonga (A3).



***** AUDIO CLIPS *****

* Sound of Receiving Signal (Equipment of the second generation)
File Type
(File Size)


Entire seaquance
PM51RT .- ..- ...- ....-
(Courtesy of JH6VZS)


Received in 1998. About 100km/60miles
away from the Bcon, using only mobile
whip. (Received & recorded by JF6DEA)

- In Jun. 2009, received by 8el YAGI
via sporadic-E. Tokyo is located about
850km/530miles away from the Bcon.
(Courtesy of JP1LRT)

- In Jun. 2009, received by 5el YAGI
via sporadic-E. JD1 is located about
1,200km/750miles away from the Bcon.
(Courtesy of JL2KJK/JD1)

- On Oct.27, 2002, received by 6ele
HB9CV.(Courtesy of XU7ACD)

- On Jan.25, 2003, received by 4ele
HB9CV. (Courtesy of XY6J)

* Sound of Receiving Signal (Original Equipment)
File Type
(File Size)

- VVV de JA6YBR JA6YBR 4501 K
In mid 80's. received by 5el YAGI
at FUKUOKA, where is about
300km/190miles away from the Bcon.

Special thanks to JH6AVS, JE1BMJ, JI6KGZ, JH6EBR, JH6VZS, JP1LRT, member of KSSG (Kyushu Six-meter SSB Group), alumni of JA6YBR; Miyazaki Univ. Radio Club and all 50MHz lovers using this beacon for their advise and supporting JA6YBR beacon operation since 1985.