Tuesday, September 29, 2015

Everything looks better from a drone

Last weekend I was invited to film a friend's property from my drone. I'm a pretty poor flyer but the result is nice. It was a fabulous day for flying.

Thursday, September 24, 2015

A weekend away at the faded Hydro Majestic

Pip and I took advantage of a "Spring Escape" in a "Heritage room" at the Hydro Majestic in Sydney's Blue Mountains.

Not being from Sydney, I don't recall the glory days of old but do remember years of passing the place while it was being refurbished.

At $167 per night, the "Heritage" rooms turn out to be a nod to our convict heritage. As one reviewer on TripAdvisor writes, "there's hardly enough room to change your mind". We rang reception and paid considerably more to upgrade to a more spacious room with a nice view of the car park.

The staff were nice and presumably we're not the first to react this way to a room even they refer to as "compact".

There's not much to do at the place but compete for a chair that gives a glimpse of the pleasant view.

Some cushions would be a nice addition. The free Wifi is very slow but functional.

Drop in for a glass of wine on the way to an AirBNB but I don't recommend staying here. Staff were nice though and General Manager Ralf B is amusingly responsive on review sites.

Sunday, September 06, 2015

ozQRP MDT Double Sideband transceiver kit review

I learned of the Minimalist Double Sideband Transceiver (MDT) kit from the video review by VK3YE and thought it might be a fun project.

The price is $75 but it includes everything you need except a microphone. The parts are well packed and clearly marked. The circuit board is excellent quality and all parts fitted well.

The manual is very clear and I found construction quite smooth.

The only confusion I experienced was figuring out which way around the BD139 transistors go in the board (the label side is closest to the edge of the board).

I spent a lazy Saturday on and off doing the build in short bursts. Late in the afternoon I was tuning around and the direct conversion receiver sounds excellent. The carrier nulling was easy and from what I can hear off air transmit audio sounds good. So far no one has responded to my CQ calls for a report but I'll get back to you when that milestone is passed.

It's a great kit for a constructor with at least a little experience. A very compact rig that could be good to take on a hike.

Update: First contact with Mal, VK2BMS who said the audio sounds good although a little basey - which is probably more due to the microphone than anything. Mid dial was 7.10604 so that's good to know.

With the second varicap link open mine covers 7.090 - 7.127MHz. Tuning is quite sensitive so I wouldn't want more range without a multi-turn pot so I think this is a good range.

Just had another contact with Ian, VK3AXH in Ballarat who gave me a 5 and 3. He's running 200W and I'm running about 2W DSB. He commented that the rig is "doing a remarkable job". I do find that after switch on it drifts a bit but it's a pleasure to use.

Tuesday, September 01, 2015

Radio data link for $1

John, VK2ASU, showed a little data link he'd built at a recent home brew group meeting at Dural and I've started experimenting.

Here's the transmitter.

They only say it’s on 433MHz but mine seems to be on about 433.9112. I can pick it up on a little hand held scanner and given that there’s no antenna connected the range seems excellent. There is a plated hole to add an antenna. I make it 17cm for a quarter wave.

I’m using RadioHead’s ASK mode here.

With an arduino sketch example.

These are the modules I bought for $1 (including postage) on ebay.

Applications of such a link are things like sending back temperature or battery voltage readings from remote sensors.

My plan is to slow down the transmission rate, test on uhf and then get it to work on 40m with the Frog sounds transceiver.