8 Nov 2012

Building requests

In the last 24 hours I've had a couple of requests from people asking me if I'd build some of my projects for them. One person asked if I'd build them a Pipit 15m transceiver and another a 472kHz transverter. Regretfully I had to say sorry that I could not.

It is not that I don't want to. Rather, it is because I don't have enough spare time! I've so many projects on the go currently, and a stack more in my head waiting to get started, as well as trying to live a normal family life doing the usual chores. Then we have the grandchildren who take time, not that we mind this at all.  So, please do not ask if I can build projects for you. I always try to help with advice and suggestions when asked - I try to respond within 24 hours unless I am away -  but I do not want to do building.

Quite a few of my projects would benefit from a small PCB. This is also something that I rarely get around to because I've already moved on to something else. There is probably a small business possible, if I was inclined, designing projects, making a PCB and selling kits. This is unlikely ever to make me rich though and I'd prefer to be a source of ideas instead.

Norway on 4m

The Norwegian authorities have granted further access to parts of the 4m band (70.1875 - 70.2625MHz), with some regional limitations. This is great news for 4m where more and more countries are now gaining access. The following chart on the Four Metres Website (I've linked to it here) shows the countries with 4m allocations currently.

6 Nov 2012

Norway gets 472-479kHz right away

Norway has been granted immediate access to the new MF band with CW and all digital modes permitted. See  https://www.nrrl.no/318-news/latest-news/492-lb1g .  I hope some LA stations come on to WSPR in the new band this evening.

More 474.2kHz WSPR

This evening I am copying 3 stations, so far, on 474.2kHz USB dial WSPR: SM6BHZ and DK7FC are both good signals with QSB but I've also copied DL3ZID at -27dB S/N. QSB is slow and it takes about 12 minutes for DK7FC's signal to go from -27dB S/N to -12dB S/N.

Lesser Chirpy 10m transceiver

You may recall that some months back I did a tiny transceiver for 10m CW ....that chirped. Well, this is the latest version that does NOT chirp! Instead of keying the oscillator current, I now key the capacitor that sets the oscillator frequency instead i.e. FSK keying. The latest version is shown here. Have a go: 10m is is good shape and you may get a few QSOs.
If the going gets tough (the RX audio level is low!) try adding an extra antenna change-over switch so you can receive on an external receiver instead. or add a 100n from TR2 collector and feed the signal into a sound card and SDR so you can use the PC's audio gain to help with copy and tune either side a few kHz.

472kHz transverter (rev K)

Several people have now built versions of my 472/500kHz transverter. The latest version is shown below which includes provision for an additional low pass filter when using a fairly long (less sharply tuned) antenna. Although some capacitors could be combined to reduce the component count, I've shown it using readily available high voltage capacitors. The 16uH inductors are 43turns of 0.71mm wire on 22mm white PVC pipe.
In the last few minutes I've been looking on 472kHz WSPR and see that SM6BHZ and DK7FC are coming through OK despite my S8 noise floor.
SM6BHZ and DK7FC this afternoon on 472kHz WSPR

5 Nov 2012

December's Practical Wireless

The December 2012 edition of "Practical Wireless" has my article about the 2m AM Fredbox and the 6m AM Sixbox transceivers that are described in more detail on my website. These simple QRP VHF transceivers proved to me that you don't need to spend lots of money to make simple transceivers that work. Both have produce interesting QSOs: the 2m Fredbox had several 90km QSOs with one at 160km, despite being only 10mW output and using just a whip antenna!

Today there is not that much AM activity on the bands but I think this is a great pity as the mode has a lot to offer. I do hope the RSGB can be (eventually) persuaded to add 144.55MHz as the AM calling/working frequency in the band plan. It is mentioned (almost lost) in the foot notes, but it needs to be properly shown. For some reason the RSGB seems to have a problem with 2m AM.

I hope others will build simple AM gear for 144.55MHz or crystal up some ex-commercial PMR radios and again enjoy the fun of 2m AM. Second hand AM gear for 4m and 2m can often be obtained for just a few pounds as no-one wants it.

GPS Route Logger

Last week I bought a Ventus G730 GPS Route Logger from Martin Lynch for £34.95. Today I tried it out for the first time on a walk in the bright autumn sunshine at Ickworth park, near Bury St Edmunds. I am totally delighted with it.

The map below shows the route taken as plotted on Google Earth. The data that comes out of the logger shows route taken, speed (average and instantaneous) , distance traveled, and altitude up and down. If linked to a digital camera file it can be used to geotag photos on a walk. I am very impressed that something this small shoved in your pocket can produce such fun results. I now need to find a use for this in my amateur radio experiments.
Google Earth plot of a walk today using data from the Ventus GPS logger

4 Nov 2012

500kHz WSPR tonight

My last post with this title got corrupted when I tried to edit it, so this is a shortened revised version. 500kHz WSPR this evening has been very good. In the last couple of hours I've been getting 8-9 reports with each transmission slot when running less than 50mW ERP. Best DX 707km to DG3LV.
500kHz WSPR reports this evening
I've downloaded the latest version of JT9 software and hope to try this for 2-way QSOs later this week on 500kHz. My current problem is the S8 noise floor which I hope to reduce by using a better sited E-field probe or loop antenna (for RX only) further away from the house.

There are still plenty of CW stations on 500kHz. One evening last week I had a very enjoyable CW QSO on the band with G3XIZ. Semi-locally there are around 3-4 stations on a regular Sunday morning 500kHz CW net.

1 Nov 2012

Projects pause

This week I am having a bit of a rest from amateur radio. We have two of our little grandchildren staying with us until Sunday and they take top priority. Anyway, one sleeps in my bedroom shack!  So it is off to ride on toy tractors, eating some cakes in a cafe and help Grampy deliver poppies.

With the XYL and grandchildren
There are some geomagnetic storms around so HF conditions are unlikely to be very good for operating.

Next week should see me back in action. My first task is to make some changes to the 472/500kHz transverter - adding an additional filter as shown in the Rev H schematic on my website so that it meets FCC requirements before an article on the small transverter appears in QST magazine next year all being well. It has been accepted. I've also got to update the schematic and parts list.

Next on the list is probably to get my 10m halo down for its rebuild that didn't get done last week. Then I am in to several possibilities including getting "Lesser Chirpy" going on air (the chirp free version of Chirpy) and casing it up. Also, there is the 481THz NLOS beacon with those BIG powerful LEDs I bought a month or so ago. There is also a new 136kHz transverter (like the 472kHz design but for 136kHz instead). And then there are all sorts of other ideas floating around in my head which probably won't get done for another year. These include a simple Fredbox version for 10m AM, an ultra-stable GPS locked frequency source to use on VLF and maybe microwaves later,  my permanent E-field probe and grabber for VLF/LF/MF,  an improved 136kHz stand-alone receiver, etc, etc. Hey ho!