Sunday, June 19, 2011

Interesting memorial to 2FC transmitter

A busy ham radio day here at 'chez vk2tpm'. A few weeks back, when I'd built the "shambles" 80m transceiver, I emailed a very strong local station, Malcolm VK2BMS, asking to arrange a contact so I could get a signal report. Here's the transceiver (double side band tx, direct conversion receive):

Shambles tx

Malcolm replied to my email some months after I sent it - apparently his cat uses the computer, presumably to upload cat videos to YouTube, and he's only just got it back. We had a contact today after the WIA broadcast and he says I sound pretty good if I don't over-drive.

He, and Robert, VK2ZNZ mentioned a plaque in the pavement at the corner of Edinburgh road and Eastern Valley Way, not far from the home QTH, and we headed off to take a look:

2FC memorial

"Radio Broadcasting Station 2FC

2FC began broadcasting on 5/12/1923. Farmer and Company Limited Broadcasting Service leased land from the corner of Edinburgh Road and Lyle Street (now part of Eastern Valley Way) to halfway to Sugarloaf Creek. Powered by 5,000 watts, it was 'the world's largest broadcasting station' (1923 Willoughby Municipal Council Annual Report). Two steel lattice towers 200 feet high and 600 feet apart supported a squirrel type cage aerial. The main operating room and staff quarters were directly below. The studios in Pitt Street were linked to Willoughby by landline. In 1929 the transmitter, by then out of date, was dismantled and moved to Homebush Bay."

In the time when 2FC transmitted from here you had to get to the transmitter by ferry and tram.

VK2ZNZ has been busy while I've been away with a new valve receiver built in the perspex style:

Valve receiver

And it has a battery high voltage supply made from 9V cells:

High voltage battery

Sunday, June 12, 2011

MFJ-9440 QRP 40m SSB Transceiver

Back in February I ordered a low power SSB transceiver from MFJ, the MFJ-9440. In June it arrived!

Front with mic

They have versions for 75m, 40m, 20m and 10m. For US$260, you get a simple transceiver that draws low current (100mA) on receive (attractive for long listening on battery power) and puts out about 5W on transmit. The design is by K1BQT, Fred Littlefield, and is well regarded.

Construction is solid and it looks like it could survive a bit of travel without any bits dropping off. Internally it's largely surface mount which should be very robust.

Internal

Receive sensitivity is adequate but not as good as other radios here. Given the low power output I can probably only contact people who are very strong anyway. There's plenty of receive audio volume available, but there is some hiss behind it.

Coverage comes set to about 7.15Mhz to 7.35 so I shifted mine down and re-peaked the receiver.

This afternoon, I called CQ and was quickly answered by Peter, VK2NEO located in Griffith who gave me a 5 and S9 (although there was some fading). We had a good chat during which he reported that I was slowly drifting "towards 20m" but that transmit audio was "excellent".

Manly Warringah 80m sked contact Brian, VK2JE, also popped up, based near Taree and also gave a good report.

I'm pleased with the radio, it's fun to use a simple analog VFO controlled rig for a change and to not have all the buttons and menus.

It did take a long time to arrive and the front panel is a little rough in both printing and the dial pointer is slightly damaged. The meter doesn't seem to show my transmit power very much for some reason but an external meter shows about 5W peak output.

Dial closeup

It's a fun edition to the shack and the price is reasonable. Thanks to Peter and Brian for responding so quickly to my CQ on 40m. You can read the manual here.

Saturday, June 04, 2011

Technology in Tibet

I've just returned from a three week visit to Tibet and as a watcher of technology and society there was much to catch my eye. (Note the SLA battery).

House tech

Tibet is now part of China and while it's still mostly a manual subsistence farming lifestyle for much of the population, the central government is investing heavily to drag it into a more modern way of life.

Everywhere outside of large towns you can see people in traditional dress, ploughing fields either by hand or with the help of a yak. Household water comes via irrigation style water courses and sewerage is non-existent. In fact, farms gather human manure along with other dung for crop fertilisation. (Note that yak dung is dried and then burned for heating).

Despite the stone-age dimension to life, there is a lot of technology on show.

Impressive hydroelectric schemes are in place and power has been distributed across the plains to even very small mud huts which get a power meter on the side.

Electricity tower

Where there isn't mains power (and even where there is), there's widespread use of solar power. The efficient evacuated tube hot water system is on every rooftop in Lhasa. Solar electric street lighting is used in villages.

Solar kit

A 10w solar kit including panel, charger, battery and a 12V compact fluorescent lamp sells for about AU$100. We saw these in use in several homes.

House solar

Large solar cookers that look like wide satellite dishes with a cooking pot at the focus. The sell for AU$200.

Solar cooker

Lower tech solar, in the form of simple green houses with plastic over metal spines, are new and popping up everywhere meaning that vegetables are available much more than in the past. (The best thing about traditional Tibetan food is said to be the view).

Amazingly there is almost 100% mobile phone penetration and on several occasions even monks were seen using mobiles, sometimes texting inside temples.

The most common type of shop, even in small villages, is a mobile phone store. Nokia is popular as are fakes (which don't work the same, but are highly functional).

Phones

There are lots of bicycles in a variety of useful configurations for single or multiple passengers and cargo carriage. On the motorised side about half of the scooters are electric and feature a removable battery pack.

Scooter

The streets are full of recharging scooters during the day.

Scooter charging

Being very flat, Lhasa is a great place for cycling but the use of electric powered transport is very popular.

In Lhasa, the medium wave band is almost empty but FM has many stations including one in English that has Chinese lessons as part of the program. On short wave the BBC was easy to hear in the evenings along with deutche velle and one night I did hear a bit of radio Australia recognised by the waltzing Matilda chimes followed by the news theme.

Here's an interesting FM radio we saw in a few shops:

Fm radio

Radios with shortwave are widely available but people I asked didn't seem to be aware of what they might hear.

Radios

Many radios look somewhat retro, including audio cassette players, but in fact they often have the ability to play back from USB storage and have SD card readers.

Radios usb

As in the rest of china, the Internet is filtered but it seems to change day by day. The first time I tried to access my gmail hosted mail the browser bounced to the local baidu search page, but later in the trip this did work ok. I had no trouble using gmail via the exchange interface on iOS. Blogspot, Facebook and other useful domains just give a network error.

Here's a few more of the electric scooters:

Scooter umbrella

Delivering the post:

Post

Batteries are often easily removable:

Battery

Like this:

Battery 2

Many have 48V systems:

Jialing

Zai Zhong Wang:

Zai zhong wang

Notes from a tech traveller

Sorry for the break in transmission, for the past three weeks I've been on the road from Lhasa, Tibet to Kathmandu, Nepal. Most of the time was in Tibet.

Tibet

I'll write soon about the technology seen on the trip but while it's fresh here's some notes on what tech I took and how effective it was.

In general, my bag was too heavy, partially because of the wide range of temperatures (0 degree tent stays to mid 30C humid weather).

Here's the gadget list:

  • Tecsun PL-310 short wave radio
  • iPhone 4
  • iPad 2
  • Kindle DX with 3G
  • Mophie juice pack power station
  • Apple USB charger
  • Ricoh Digital III camera


Aside from the camera, the most used gadget was the PL-310 short wave radio which let me stay in touch with world news via the BBC and to some extent VOA. The BBC belted in each early evening on 17790kHz. The radio reports the strength as 53dbuV/m (with a noise floor of 24dbuV/m).

This radio is very compact, has excellent battery life, and I particularly like the automatic tuning mode which takes about two minutes to scan all of it's short wave bands and store the active frequencies. It would often find 60 stations on a scan.

Amazingly, the Kindle's free data service worked in Tibet (part of China) and as well as buying a few books (including a Lonely Planet) it meant that I could get to my email, although it's pretty slow and painful.

Kindle

The iPad is great on the plane, I read and watched some movies, the flights we took had no personal entertainment system and the "big screen" movies were in Chinese so this was good. During the trip an eInk display, like the Kindle, is more practical for the packing weight.

The Mophie battery pack was good - it's the one with a USB socket, power went out quite frequently in both Tibet and Nepal which have regular "load shedding" power cuts.

Apple's standard iPhone/iPad USB charger is about the most practical USB charger around. I took both Australian and UK mains plugs but even then it was sometimes hard to get a good mains connection to the weird wall sockets available.

Socket

The iPhone worked well as a second camera and the HDR feature was very handy trying to get detail in snow capped mountains and bright clouds. Here's a straight shot:

Normal

And here's the HDR version:

Hdr

Oddly the Telstra SIM didn't find coverage in Nepal but aside from that China Mobile's coverage is amazing throughout Tibet and right up to Everest base camp.

Internet access was pretty patchy. Some internet cafes do not offer WiFi so it was their virus ridden pirated Windows computers or nothing. Where we did get wireless internet it was very slow and unreliable but enough to check that no dramas had arisen at home.

So, for general staying in touch in low tech countries you can't beat a short wave radio even today. Rather than carrying heavy books a tablet reader makes sense in terms of weight.