LCD panel meter
reads to 30V
In the “Ask SILICON CHIP” pages of the August 2009 issue P. W. was enquiring about an LCD panel meter that could read to 30V. Jaycar have a clock/voltmeter which is supposed to handle 24V systems. It is on all the time with switchable backlight and battery condition lights. The Jaycar part number is XC0118.
I am using one in my car to monitor the condition of my second battery.
Ray Saegenschnitter, VK3UCB,
A keen cricket fan, my spouse was offended when the recent Ashes series was interrupted on ABC local radio by the football. “They say it’s on Digital – get one”, was the demand!
We live in the country, about 80km SE of Adelaide (on Lake Alexandrina) with a clear line-of-sight to the Mt Lofty transmitters. Borrowing a city friend’s DAB+ radio, I checked that indeed there was a good strong signal, so long as I was outside the house! Inside, there was nothing, the result of the thick limestone walls.
Attempts to find a Digital Radio with any sort of antenna socket were fruitless, so it looked like a lash-up to the whip antenna on a portable was in order. Presuming a high impedance at the whip, I set up an old 75:300Ω balun on the end of the cable from our amplifier/splitter, clipped one side of the balanced output to the whip and the other to a length of hookup wire wound around the body of the radio, at the other end to the whip.
Perfect! This arrangement gave at least 4 out of 6 signal strength bars all the time, sometimes more. There was great sound, no football and a happy spouse! However, you should encourage the ABC to remember to listen to it - there are times when the transmissions disappear, repeat small bits for hours, have the wrong program and never ever believe the scrolling text display!
School zone speed monitoring
is not necessary
I have some comments about school speed zones and kids. I’ve been doing bus supervision for 34 years now and I have seen countless accidents. Unfortunately I have seen kids hit by cars. One died getting off the bus (ran out from front of bus into car passing bus, while trying to get to mum parked on the other side). The other was hit on the pedestrian crossing. Both cars were going slowly.
The causes of nearly all of the accidents I have seen have been observational and parking violations NOT speed. They include drivers double parking, parking in no stopping zones, in the middle of the street even, pushing in, blocking bus lanes and turning circles, opening doors, making U-turns, reversing and general stupidity.
The point of my letter is that it would be more effective, in terms of safety, to focus the RTA cameras at the school bus, no stopping, no standing and drop off only zones, and nearby parking spaces, rather than using the technology just to monitor the through traffic.
Random sampling of scanned and recorded sites would be an effective and efficient method of monitoring the process and could yield thousands of dollars in revenue a week from many schools.
On a completely unrelated subject, please be advised that the NSW Board of Studies has reclassified the subject of Industrial Technology, at the HSC level, as a category A subject. It is now on par with the sciences and maths in terms of subject status and due recognition by universities. This includes the focus area of electronics technologies of course.
Well done to the many teachers who have been pushing for such accreditation over the past years.
Comment: that’s good news about the upgrade of Industrial Technology.