Sunday’s chasing…

“There is nothing quite so much fun, as messing about with Radio”

After a couple of months of not chasing much SOTA with life getting in the way, I was able to fire up the HF rig from around 8:30 am on Sunday morning and have a good listen around. I was able to pretty much keep the rig on all day and listen out for the goat bleating alert from the most excellent SOTAgoat app to let me know of what was happening around VK!

This is what I ended up with for the day, between chores, shopping, and some plumbing repairs and the construction of an End Fed Half Wave for 40M

18/May/2013 23:42 VK1DI/P VK1/AC-038 Mt Tuggeranong 7MHz SSB
18/May/2013 23:46 VK3MRG/P VK3/VC-007 Mt Macedon 7MHz SSB
18/May/2013 23:47 VK3KAN/P VK3/VS-049 Crowsnest Lookout 7MHz SSB
19/May/2013 00:05 VK3YY/P VK3/VE-011 Mt Stirling 7MHz SSB
19/May/2013 00:05 VK3KAB/P VK3/VE-011 Mt Stirling 7MHz SSB
19/May/2013 00:12 VK3KAN/P VK3/VS-049 Crowsnest Lookout 7MHz SSB
19/May/2013 00:50 VK5PAS/P VK5/SE-009 VK5/SE-009 7MHz SSB
19/May/2013 01:18 VK5CZ/P VK5/SE-009 VK5/SE-009 7MHz SSB
19/May/2013 04:30 VK5PAS/P VK5/SE-002 Mt Cone 7MHz SSB
19/May/2013 06:22 VK3MRG/P VK3/VC-034 Pretty Sally 7MHz SSB
19/May/2013 06:27 VK3YY/P VK3/VE-204 The Paps 7MHz SSB
19/May/2013 06:51 VK3HRA/P VK3/VC-002 Mt Donna Buang 7MHz SSB

Highlight for me was the final contact of the day with Alan VK3HRA/P on the new antenna.

Testing out the EFHW with Alan, VK3HRA/P who was on Mt Donna Buang…

Advertisement

The end Fed Half Wave (EFHW) for SOTA portable operation…

The End Fed Half Wave antenna (EFHW)for SOTA portable operation…from bits and pieces in the Junkbox…

Whilst leisurely chasing activators this morning, I also took the opportunity to rummage through my Junkbox to see if I had all the bits and pieces to make an end fed half wave antenna for the 40M band. My main antenna for 40m at the home station is a Butternut HF2V, and is a good performer for SOTA chasing work, but I intend to activate a few summits in the near future, and although I’m well equipped for VHF, I need a good portable antenna for my planned activations.

I did a bit of research on the EFHW during the previous week, looking at what was written on the Internet about the antenna and what kits, if any, were available and at what cost. I found a few, but decided that the best way forward was to knock one up with the stuff I had on hand…

There’s not much to them, and the whole thing took me about 2 hours to assemble.

The VK5LA EFHW Tuner

Firstly, The circuit – There seemed to be a fair variation on the theme in terms of components used but ultimately, it’s just a tuned circuit set to resonate at the frequency of interest. Matching – some used link coupling of the tuned circuit, some with a tap up a few turns from the earthy end of the inductor. I went with this…

Hand drawn Circuit

Quite a few of the circuits used the Yellow toroid but I didn’t have one so I used a T50(Red) one that I had on hand. 24 Turns was about average for the schematics I gleaned and the tap 3 turns in from the earthy end seemed to be standard. The capacitor was one I had on hand that came from the board of a 70’s am transistor radio that was long ago junked.

Wiring diagram

I had a small black plastic Jiffy box on hand so I mounted everything in it and soldered it up as per the above diagram. The red banana plug socket on the side was added just in case if I need it for later. The black banana plug socket is for a counterpoise wire if desired. I found that I didn’t need one when testing, I think because I’m using a tap on the inductor L1. Dead simple!

A peek inside…

I then cut a 21.6 m length of light weight hook-up wire for the 40M band and attached a banana plug to one end and a lug to the other. I attached the lug end to the tip of my 9 meter high Squid Pole that I had set up in the front yard, and the other end to the Tuner and FT817 via a short BNC to PL259 lead set up on a table.

Table top portable…in the front yard!

To be perfectly honest, I wasn’t really expecting it to work, I plugged it in and turned the FT817 to the 40m band and selected LSB…the dial was down at the bottom of the band and to my surprise I heard a few stations as I tuned up to around 7.1 MHz. Well, “here goes nothing” I thought as I began to turn the variable cap on the tuner, all of a sudden the noise sharply increased and a smile emerged on my face! I knew then it was working and a brief “VK5LA testing” on a clear frequency allowed me to adjust the SWR to nothing on the Rig with the Variable capacitor at around 1/2 mesh…pretty well where it should be…

The complete EFHW 40M antenna packs down to a small package…

Now the acid test! did it work? could it make contact? It seems that it was certainly hearing ok, with a lively 40m band jumping out at me…I was about to find out as heard the bleat of my SOTAgoat alert on my iPad, letting me know that Alan, VK3HRA/P on VK3/VC-002 Mt Donna Buang was calling CQ on 7.103 MHz. I tuned to his frequency, and he was a good signal, very readable at 56…To my delight, Alan came back with a 58 for me for my first EFHW contact.

I’m certainly impressed by the EFHW antenna, and I’m looking forward to giving it a run out on a summit in the very near future…in the mean time, I’ll try different configurations like an inverted L and V, and perhaps as a vertical, to see how it goes. I might even adapt it by making the wire “linkable” for 10/15/20/40 like the Link Dipole that others swear by.

Experimenting is the essence of Ham Radio!!!

Andy – VK5LA

WSPR on the 2M band 144.489 Mhz

WSPR – having fun on HF/VHF while doing other things…

One of the best things about Ham Radio is that if your interest level wanes or you’re just too damn busy with life to sit at a transceiver and make contacts then there is always WSPR!

A few stations in VK land are using WSPR to see just what happens on a daily basis propagation wise. Interestingly, stations are hearing each other out to 750+km (VK1 to VK5) at low power levels, even when the time of day and WX conditions would have conventional thinking saying, “no way!”

So what is this WSPR stuff, anyway?

WSPR stands for Weak Signal Propagation Reporter, and is a mode of transmission that is ideally suited if you don’t want or can’t spend time in front of as radio. Its software that runs on your PC (Win/Linux/Mac) and the PC connects to your rig just like if you were using a digital mode like RTTY or PSK31. You probably have all the stuff you need.

WSPR works on all bands to 2 M and beyond, indeed,  WSPR on the HF bands is extremely popular and you’ll find many hams on all of the common HF and WARC bands spotting signals from around the world in real time, and uploading the data to the wsprnet site.

What kind of computer and Rig do I need?

WSPR will run on a fairly low spec computer, and most shack computers will run it fine. I’m actually using an old Toshiba satellite pro laptop that has a Celeron processor  – running Linux – and it works a treat. As for the Rig, again, just about anything will work as long as it’s frequency stability is good. I’d probably give Valve, or Valve hybrid jobs a miss though. At VHF however, the rigs need to be all the more stable…I use a little Yaesu FT817 as my WSPR radio, and i’ve modified it so that it is frequency locked to a Rubidium standard. This ensures that the radio wont drift when it cycles between TX and RX., or is affected by the temperature in the shack. This would be overkill on HF WSPR, but I WSPR on the 2M band, where drift is an issue. Some rigs like the TS2000 drift too much on 2M and above to be unsuitable for the mode. It’s also important to observe the usual precautions when using a sound card mode with a transciever – make sure any speach processing is off, and adjust the rig so there is little or no ALC indicated when TXing. This ensures you are not overdriving and splattering all over the band…

For the interface between the PC and the Radio, then a Tigertronics Signalink or similar interface is the way to go if you don’t want to bother with building anything.

These things work marvellously and you can order it with a cable for your particular radio for a solder free plug and play experience…

If you just want to do HF WSPR, then the Icom 7200 is just about the ideal rig, as it has a built-in USB port that provides a 1 cable solution  between the pc and Rig. other USB capable rigs are equally awesome for hooking up to WSPR…

With WSPR, once it’s up and running, you can just set and forget. When you have a spare moment, at work or home just look at the wsprnet page and see who’s hearing you, and who you’re hearing…

How?

Download the software for your operating system from the below site…note that the Linux packages are broken and don’t work.

http://physics.princeton.edu/pulsar/K1JT/wspr.html

If you want to use Linux then the very aptly named George Smart has some instructions here for getting it to run under Linux…

http://www.george-smart.co.uk/wiki/Compiling_WSPR

On time, every time…

Next, make sure you PC’s clock is set EXACTLY – be anal about this as it won’t work properly if it’s out by more than a couple of seconds…make sure it’s synchronised with an internet time-server…http://www.timesynctool.com/ is one of the better ones. alternatively, you can just use set windows time and date to sync with a time server.

Once the software is  installed you’ll need to configure it with some basic info, like your call sign, grid locator, soundcard input and output, PTT method, CAT control (if any) and how much power you’ll be running…you can then set your Rig to the desired band and tune it to the “dial” frequency (displayed in the software screen) – i.e for the 30M band the dial frequency is 10.138700Mhz USB

When all is well, set the TX slider to say 10%, make sure upload spots is checked and TX idle is unchecked. Your rig will listen in 2 minute blocks, and if it hears a station and successfully decodes the call/locator/power level information from a Transmitting station, it will upload the info to the wsprnet site for display. At 10% TX, it will switch to transmit for a 2 minute block every 20 minutes or so…and you will hopefully be heard far away!

Then What?

WSPR’s main “port of call” if you like, is http://wsprnet.org/drupal/wsprnet/spots this is where everyone goes to look to see where and how far their transmissions are being heard at any time of the day or night. Don’t be surprised to see your 5 watts get spotted by stations 1000’s of km away on HF, and 100’s of km on VHF. There are lots of statistics available on the site, along with maps, various forum and even chat.

So there you have it, if your time is precious but you still want to keep your finger on the pulse of ham radio, then a little WSPRing might be for you…