500kHz REAL DX with the new transverter

DX reports on 500kHz WSPR this evening using the new 10W transverter

My new 500kHz transverter has "done the business" with reception this evening of my WSPR signal (for the third autumn running) by OH1LSQ at a distance of 1736km. What I find incredible is that this is with low milliwatts ERP from an antenna that is tiny: the outer of the 6m vertical coax (the feed to my 10m halo) tuned against a ground formed by my central heating system copper and brought to resonance with a tapped coil on a ferrite rod sitting on the shack desktop.

500kHz WSPR reports map

The new 472kHz band is clearly going to be great fun for all, even without anything special in the way of antennas. However, my experience with small antennas on 136kHz is a different matter: on that band it is MUCH harder to get reports from any distance with QRP.

For details of my 472/500kHz transverter see https://sites.google.com/site/g3xbmqrp/Home/472khz-transverter

QRPtransceiver.com website

http://www.qrptransceiver.com/website

This website looks a useful resource for anyone wanting to find out about the commercial QRP radios on the market. As far as I can tell it lists virtually every QRP radio there is and gives some information/links about every one. Well worth a visit and I am surprised I've not seen it before (or at least if I did I had forgotten it!). The link is http://www.qrptransceiver.com/ .

GPS tracking?

Some help needed......

When out in the field locally receiving my VLF and LF test transmissions from home, it would be very helpful to be able to plot signal strength against location. For example, if doing a drive test, with an E-field probe antenna on the car feeding an LF RX and PC audio package such as Spectran, it would be excellent to be able to plot a map or database showing field strength and location. Now I have to confess I haven't a clue where to start! My knowledge of GPS is almost zero and my PC skills are limited to MS Word and simple spreadsheets in Excel (some years ago). So, if anyone knows of a SIMPLE way of achieving this goal please let me know.

On a related subject, what is the best, low cost, pocket GPS tracker that would record a walk (distance, track taken, times) and allow this to be plotted on a map when one gets home?

10m Simple Sideband (DSB) Transceiver

Regular readers of this blog will recall that about a year ago I started breadboarding a simple DSB speech transceiver for 10m. Having had great success with the WISPY 10m WSPR transceiver, I now have a very simple design for the TX part of such a DSB speech transceiver (just need to add an audio preamp/clipper/filter), so I am beginning to get ideas together for this project again. A power of around 1W pep (DSB) equivalent to 500mW pep SSB is the minimum I think. On RX a single balanced diode mixer (or a double balanced mixer such as an ADE-1 or SBL1) should be fine. For the VFO, I am thinking of a mixer/VFO with a tuning range of 28.4-28.6MHz. The RX audio design from WISPY works well but it will need another audio stage to drive headphones.

I want to have another go at a 136kHz transverter (based on my latest architecture), more non-line-of-sight (NLOS) optical comms, E-field probes, more earth mode comms, WSPR beacons for other bands,  etc etc...

My problem is I've too many ideas in my head and not enough hours in the day to try them all out. What I need is a spare, free, design team (!) to take these ideas forward whilst I get on with other things, like looking after the grandchildren, gardening, maintaining the house, eating and sleeping etc. Since retiring 4 years ago I have no idea why I've no spare time!

500kHz WSPR - 990km already tonight

This map shows people who have copied my 500kHz WSPR signal (using the new transverter) up to 11.20pm tonight. Best DX report so far is DL4RAJ at 990km from near the Czech border who gave me an astounding +5dB S/N report, a signal level good enough for a CW QSO.

472/500kHz transverter FINISHED

Today I completed the rev E version of my 10W transverter. In the end I reverted to a double balanced mixer and this immediately solved my issues with mixer stability that I had with the transistor mixer design. Air testing this evening, I am getting plenty of reports but a slight drive is noticable in the reports, probably as I am using a small plastic box and the PA heatsink warming is causing the 3.2MHz crystal to move about 1Hz during the WSPR TX cycle. It really needs a bit bigger metal box, but it will do.

The lastest transverter schematic (there may be value errors)

WSPR reports 20.9.12 with the above transverter and 6m long antenna

The desktop 472/500kHz station, ATU (don't laugh!) and antenna current meter

Japan Ham Fair 2012

http://onjapan.net/2012/hamfair/icom-kenwood-yaesu.html

The recent Japanese ham fair in Tokyo showcased the latest products about to hit the market in the coming months. Included was the IC-7100 all-mode, all band (including 4m) 100W mobile. What was not there was the long awaited FT-817 replacement.  A product I have not seen mentioned yet is the Yaesu FTM-400D digital VHF/UHF radio. I don't think this is a D-star radio, so what form of digital modulation does it use? Is this a Japan only product?

WSPR for the iPod Touch

Like many these days, I've an Apple iPod Touch and use it every day for web browsing. When watching the TV or reading the paper it is handy to be able to check my WSPR spots with a quick look at the iPod Touch.

The Apple iPhone, iPad and iPod Touch do not have that many amateur radio apps. There are a few very useful ones like an audio spectrum analyser, an oscilloscope, Echolink and a repeater database, but what I would really like is a full WSPR interface for the iPod Touch.  Does anyone know if such an app has/is being developed for Apple or Android products? Even Apple OS PCs seem to be less well catered for with regard to amateur radio software.

Further WSPR development?

On the LF reflector recently there's been discussion about how to make weak signal modes decode at even lower S/N ratios. Joe Taylor K1JT, who created WSPR, was approached by Stefan DK7FC, a very well known LF DXer, to see if WSPR could be further developed to achieve this.  One idea is a slower version of WSPR with a 4 or 8 minute time slot instead of the current 2 minute period. Theoretically it should be possible to get successful decodes with much weaker signals. Joe is currently busy with other work, but took kindly to Stefan's suggestion and said he would take a look later in the year.  With WSPR performance roughly equivalent to QRSS10, such a move would be welcomed by many of us trying to get reports on VLF, LF and MF with QRP.

472kHz transverter - real progress

Since reverting to a passive double balanced mixer based design, the circuit is now behaving properly with no signs of oscillation and a good clean signal from the PA. Although I have used an SBL1 mixer, it will work with any similar mixer package. Tomorrow I may try the design with an NE602 as this would allow the separate oscillator to be removed. With an NE602 it should be possible to do the complete TX-RX transverter with 1 IC, 2 transistors and 1 FET.  Now THAT would be neat.