Pedestrian Portable HF DXing

G3XBM operating pedestrian portable in South Devon

The latest edition of Practical Wireless carries my article on pedestrian portable HF DXing. Getting out of doors in a noise free location with a simple HF rig and using it handheld - not with a large semi-permanent antenna, but with a whip on the rig - is one of the great pleasures of QRPing. With a good location, such as a clifftop site with a slope towards the sea, DX can be worked easier than might be expected even with a few watts of SSB.  Nothing quite beats talking to a station thousands of miles away with a small radio in the hand.  A small counterpoise wire is a must to get the best results. Especially in the summer Es season when signals can be S9, this can bring a whole new dimension to the hobby. Forget that plasma TV interference and get out there in the great outdoors!  Best bands are 15m, 10m and 6m (when open).

Nice blog site with useful info

A nice Pixie transceiver and tuner on the PD7MAA blogsite

Graham G8NWC has just told me about a very nice blog site with some useful QRP information. See http://pa-11019.blogspot.co.uk/.  It is surprising how much GOOD data there is out there when you look around!

Simple antenna current meter

https://sites.google.com/site/arvidevans/LED_Antenna_Current_Indicator.png

Just spotted this on the web. Looks like a useful idea to indicate antenna current and could not be simpler.

Simple pleasures

Today for a change, and whilst waiting for the family and grandchildren to arrive for half term holiday, I simply went on 20 and 15m and just operated using the 2.5W pep SSB from the FT817.  No great DX, with the best contact being OY, but a few nice enjoyable contacts in the log. The speech processor certainly helps.

It is tempting now to build a multi-band VXO controlled QRP CW transmitter to use with the FT817 (on receive) as it is a while since I operated QRP CW on 40 and 20m. With the EF-10/20/40 antenna now up it is an ideal time to do this and enjoy the simple pleasures of operating QRP on the HF bands again. In my mind I think a 2N3904 VXO and buffer followed by an IRF510 PA at around 2-3W.

Par EF-10/20/40 Antenna and a comparison

This afternoon I decided to take down my 10m halo for a while and replace it with a lower antenna: the LNR Precision (was Par) EF-10/20/40 end fed wire antenna, which I've owned for some years but not used recently. As it suggests, it covers 10, 20 and 40m with a very low SWR, although it is a reasonable match on several other HF bands too.

See http://www.hamradio.me/antennas/lnr-precision-ef-102040mkii-test-data.html for an analysis of this antenna.  The antenna works very well and on 40 and 20m WSPR I was getting plenty of spots with 500mW to 5W.

Photo on http://www.hamradio.me website of the Par antenna

On 40m I did a comparison between the horizontal EF antenna and the earth-electrode antenna. A series of transmissions was made with each antenna in turn, then I compared WSPR spot S/N received from a number of stations.

The conclusion is the earth-electrode antenna is around 9-16dB down on the EF antenna on 40m, so averaging about 2.5 S-points down. The test is not too accurate as conditions change, the earth-electrode and EF have some directivity and the reports sample size was small.

Grandchildren time and new projects

We've all 4 grandchildren coming to stay at different times over the next couple of weeks. As usual, this means that amateur radio activity will decrease somewhat as the upstairs shack gets used as a real bedroom again. It will still be possible to run WSPR on LF and MF and some of the HF bands from time-to-time, but not in the evenings.

Whilst this "interlude" is going on, it will be a good time to take stock and think of the next projects. The early part of 2013 has seen a burst of activity related to the earth-electrode antenna and the ferrite rod TX antenna, neither of which was planned. I also did some more work on a 136kHz transverter Several projects, including the 136kHz transverter, are still unfinished:

Tenbox 10m AM transceiver
Although most of this has been breadboarded and is working, it still has to be boxed and properly documented. I quite fancy a PCB for this simple design and that needs to be created.

471THz over-the-horizon tests
My PhlatLED very high power LEDs have yet to be switched on and I still have to build a more sensitive detector.

De-cluttering and Test equipment
With a move to a new QTH later this summer I really ought to think about de-cluttering and sell some lesser-used radio equipment. At the same time I could do with building some more pieces of simple test equipment such as a proper QRP power meter, a resistive SWR bridge, a better ATU, and a very basic spectrum analyser.

Other projects
There is a list as long as my arm of other projects I'd like to tackle, but it takes me all my time to do the ones I do! 

IC7100 Sneak Preview Video

There is a short YouTube video clip from ICOM America describing the IC7100 with a look at the various connections on the head and main unit. The thing that impressed me was just how small this transceiver is. It looked larger in the earlier pictures. The IC7100 is likely to be on sale in the UK in late spring at around £1700-1800 without the D-star option. Not cheap, but a lot of radio.

The specification of the IC7100 is available here.

Hard to believe this is without a conventional antenna

As 40m went rather quiet, I QSYed to 80m WSPR on the earth-electrode antenna this evening. The log below is from just one single 2 minute transmission with 2W.

12 spots in one 2min burst this evening with 20m spaced earth-electrode antenna

Earth-electrode antenna on 40m

This evening I have been trying my stealth antenna (20m separated earth-electrodes, wire in the grass!) on 40m again and getting plenty of WSPR spots. I did try to match it on 160m earlier but couldn't get it below about 3:1 using the Elecraft T1 auto-ATU. Spots from 6 countries in an hour (LA, DL, F, EI, GM, G) with strongest reports from Cornwall (-3dB S/N) which is in the line of the wires/loop.

WSPR spots received using 20m spaced earth-electrode antenna with NOTHING in the air.
 

Earlier today I had a visit from Ted G4NUA, so I showed him my 137kHz antenna, "Where is it?" he said. Exactly - the wire runs back to the house from the far earth rod IN the grass and it is all but invisible!

Earth-electrode antenna on 80m

This evening I have been using the 20m baseline earth-electrode antenna on 80m. From the shack (upstairs) there is a 20m coax down to the back of the garage where it picks up the earth electrode wires. On 160m the match is poor but on 80m a near perfect 1:1 match, so no radiation from the coax.

On receive there are plenty of signals visible and decoding on WSPR and on TX it seems to be getting out pretty well with 1W RF from the FT817.  I am not sure of the ERP on 80m, certainly higher than on 630m (472kHz), but it does appear to be quite effective.

Tomorrow evening I'll match the earth-electrode antenna with the Elecraft T1 auto-ATU and see how it performs on 160m. I'll put the ATU right at the earth-electrode end of the coax so that we'll see the radiation from the earth-electrodes and not the feeder.