Broadcast - 19 July 2026
Last technical night, Ross VK7ALH brought along something a little different for interest’s sake, a Barrett Communications SB250 HF SSB Marine Transceiver, another fine example of Australian manufacturing from Western Australia.
The front-panel controller PCB carries a date of 26 January 1990, placing this design at well over 30 years old, with the original series beginning back in 1987. The unit features a membrane front panel with 24 buttons, a forward facing speaker on the left, and a reasonably sized two-line LCD for channel, frequency, and operating information on the right. The only rotary controls are for volume and mute level.
One particularly interesting detail is an internal jumper that switches the set between Maritime and Land modes. In Land mode it enables Royal Flying Doctor Service, RFDS calling, while Marine mode activates 2182 kHz AM with the international emergency tone.
The SB250 supports 255 channels, typically with around 100 EPROM programmed channels and the ability to front-panel program roughly 25 more. Output power is a solid 100 watts PEP. Optional features were selective calling and telephone network interconnection.
Inside, one striking aspect is the extensive use of ribbon cable for almost all internal wiring, with only the RF inter-stage coax cable. There is no external 12 Volt plug and socket, only a directly terminated hefty figure eight power lead. The radio is built around three printed circuit boards: one for the front-panel controls and display, one for the power amplifier stage, with the main RF board on the opposite side of the case. Hidden on the main control board is the ubiquitous Zilog Z80 microprocessor paired with an Electrically Programmable Read Only Memory or EPROM. Back then, updating firmware meant physically replacing that EPROM. A tidy, well engineered piece of vintage Australian HF equipment, thanks Ross.
Hopefully no one turned up at the NTARC Club Rooms last Wednesday night, because we had all relocated to the Iron Horse Bistro - for the clubs mid-winter social get together. We all gathered about six pm for what ended up being an evening of excellent food, served in pleasant surroundings, with friends. It may have been a social evening, but as usual, much of the conversation was interspersed with radio and electronics, as always! HiHi. A great time was had by all and we eventually made our way home thoroughly satiated.
As usual pictures will be available on the NTARC Web site under “Blogs” for this broadcast. NTARC Blogs
UPCOMING EVENTS
CW course - Every Wednesday night, on 3.580 MHz from 7 to 7.30 pm. Your CW Coach for the evening is Nic, VK7WW.
On Air Test and Technical gathering - Wednesday nights, on 3.567 MHz from 7.30 pm.
Club Room Technical night - The next session will be Wednesday the 22nd July and will commence at the usual time of 6.30 pm at the Club Room Archer Street, Rocherlea.
Coffee Morning - Held every Friday in the NTARC Club rooms. Time is from 10 am to noon.
Finally - If you have any items of news please email them to the Secretary at the following address news@ntarc.net all items to be received no later than 5 pm on the Friday prior to the Broadcast.
That’s all folks,
73, Stefan VK7ZSB.
