I need your help! 

But first some background. The Index Laboratories' QRP+ is a 1990's 5W all-band QRP transceiver from the USA. I bought mine at a club sale and it was supposed to be working fine.

But it wasn't! Never mind, we all love a

challenge, don't we?

It seems that the SBL-1 mixer is a common failure point so a replacement was ordered.

The rig comprises four boards, which are stacked and have interconnecting leads.

It is relatively easy to pull apart, and the mixer is on the top board.

After a big desoldering struggle I fitted the new SBL-1 (U5), which brought the receiver back to life. Unfortunately, the TX still didn't work. Back to the drawing board.

The next stage was to replace the final PA transistor, which is on the lowest board. This is a IRF510 (Q9) and I ordered a few off Ebay. I fitted a new one and in tests I found that I could only get about 0.1W out! (on CW) with the gate bias backed off fully anticlockwise. 

Power out should be about 5W.

Anyway, that's as far as I have got. I have attached a link to the circuit diagram and would appreciate any suggestions.

Well, some replacement IRF510s were sourced from the G-QRP club (thanks guys). Apparently, there are some "fake" IRF510s around that don't play well with RF.  After pulling the radio apart (again) and replacing the transistor, it was a little better - about half a Watt output. Anyway, to cut a long story short I have passed the radio to another G-QRP club member and I hope he has more luck than I did! 

My Yaesu FT-817 and Winkey

This weekend has seen the Commonwealth Contest 2019. I documented my 2018 attempt on the blog, and was keen to give another go this year.

Last year I used my Icom IC-756 Pro 3 wound back to 5W, but this year decided to use my Yaesu FT-817 for a real QRP approach. I bought a USB lead for it this year to give full computer control with N1MM and decided to use my Winkey for full auto CW .

This year I had a slight change to my antennas. Out went the end fed half wave (with 80 loading coil) and in came a 66ft OCFD with the apex at about 8m. Also new was a quarter wave vertical for 20m, erected for the weekend on a 10m fishing pole - more of that later.

The contest ran from 10am, but at 9.30am I was struggling with the computer and interface. Stupid me forgot to turn off the keyer on the FT817 - duh!. Soon we were under way.

The contest got off to slow start with my 5W struggling to break through. Many stations just couldn’t hear me. The quarter wave vertical for 20m turned out to be a noise magnet - almost S8. I  decided to abandon it quite quickly.

After an hour I had a few stations in the log - 5B4AGN (Cyprus) and 9H1CG am (Malta), but nothing better. 3B8XF Mauritius (G3TXF) was audible, but I couldn’t break through. Same with ZF2CA Cayman Islands (both 3B8 and ZF were worked last year).

The afternoon saw Canada romping in and I ended up doing an hour at about 10-11pm, clearing up the UK HQ stations.

Sunday started at about 5.30am and a few more Canadians on 40m were cleared up. I then had a big breakthrough - VK4CT on 40m. It wasn’t easy, as they needed three or four repeats on their serial number, but we got there eventually.

So there you go - 34 QSOs in total, which doesn’t sound much, but I didn’t take part for the full 24 hours and it is HARD work with only 5W. Peter M0RYB, a fellow Norfolk Amateur Radio Club member, cleaned up with 70 QSOs in the QRP section. Must find out his secret!

Click to enlarge

Don't you just love it when something works! I took down my multi-band end fed half wave (EFHW) antenna last weekend and replaced it with a home-made 40m off-centre fed dipole (OCFD).

The EFHW worked, but I was never happy with the performance. This may be due to the inverted L configuration or the compromise 49:1 ferrite-based Un-Un. Either way, I felt I was missing out on some DX and was keen to try something else for the Autumn/Winter.

The 40m Windom is about 66ft long and has a home-made 4:1 Guanella balun made with two ferrite cores. It is fed at the 41%/59% point so it covers 40, 20, 15 and 10m with an SWR below 3:1 and the other HF bands with an ATU.

The apex is at about 8m with the ends down to about two metres, so not ideal.

Nevertheless, in back-to-back WSPR tests it proved to be better than my W5GI dipole that goes over the roof by about 7dB on average. This was good as the EFHW was mostly down on the W5GI.

Anyway, I thought I would leave it running on 20m WSPR for 24 hours to see what it could pick up. This was with zero sunspots, but a Kp index of 1. I was delighted to see that I had been picked up as far afield as Japan, Australia, Alaska, Antarctica and Brazil. The furthest west I got in the US was Utah.

So, I'm a happier bunny. I might return to the multiband EFHW one day, perhaps looking at different ferrite mix configurations for the Un-Un, but for now I'll stick with monoband EFHWs with tuned iron toroid/capacitor matching units that work well.

The OCFD can stay up for a while - you know that the best antenna you can have is either the one you just took down, or the one you are going to put up, not the one you are using!

I've had my 20m QCX kit working now since just after Christmas. While the build was quite straightforward I did have a few problems.

Click to enlarge the photograph by the way.

The first was that I managed to blow the 7805 regulator while leaving the radio running on WSPR one morning. Having replaced that I found that the rig was quieter and there was no TX output any more. Thinking I had also blown the PA transistors I replaced all three of the BS170s, but that didn't help either.

Anyway, after a lot of help on the QCX reflector I decided that the fault had also taken out the 74ACT00N chip. This had been soldered onto the board directly so had to be cut out with a Dremel and a new IC socket installed.

And after finding a short somewhere near the PA transistors all was well - success! Output using a 12.6V Lithium battery pack was about 1.8W

I have been using it on and off ever since as it has a really nice receiver - even took it to North Norfolk as I detailed in another post.

But one thing always bugged me - why only 1.8W? When I built it originally I was getting more like 3W, so perhaps it was the replacement BS170 transistors, which came off Ebay on a slow boat from China.

So having a few hours free today I ignored my own "if it ain't broke don't fix it" mantra and pulled it apart. I replaced all three BS170s with new ones bought from the GQRP club and while I was at it I replaced C22 with a 0.1uF capacitor to try and soften the sidetone a little.

I managed to break one of the wires to one of the control buttons on the front in the process, but it is now all back together.

And the power output is now just under 3W with 12.6V - success! I have no doubt I could get more if I messed around with the band pass filter, but I don't think it is worth it. I tend not to run it on 13.8V as the regulator gets VERY hot indeed.

Anyway, it is a great little radio and will be going on some more journeys no doubt.

I can thoroughly recommend it as a kit project - see QRPLabs site. My case came from Banggood in China and only cost  a few pounds. It did take about 10 hours to machine (posh word for drilling out with a Black and Decker and attacking it with a file).

The label was produced in Photoshop and printed off by Photobox.co.uk. I ruined the first one by spraying it with varnish, which made the dye run. Luckily I have a few more spares and may eventually cover one in sticky-back plastic. But for now it looks great.

The red buttons were bought just before Maplin went bust so are a lasting tribute to what was one of my favourite shops and the result of much ribbing by the family every time I went there - RIP Maplin.

Today was 2018 ”Bumps on the Air” day for me. Because we don’t have any summits in Norfolk I have to make do with tiny hills, or bumps!

Two years ago Jim G3YLA and I climbed up Beeston Bump (63m) and did some amateur radio operating. This year I wanted to beat that so drove to Norfolk’s mightiest peak – Beacon Hill near West Runton at 103m. Ta dah!

Actually, this wasn’t a very exciting spot as there are just two rotting benches, a flag pole and trees all around.

Nevertheless, I set up my end fed half wave vertical on a 10m fishing pole and connected up my Yaesu FT817. There wasn’t too much about but I worked John F5VKU (also G8MM) near Cannes with 5W SSB. He said he was struggling to hear me.

My 20m QCX radio - click to enlarge any image.

After playing with SSB for a bit and failing to break some pile ups I connected up my 20m QCX radio and tried some CW. I was really surprised as Karl IV3RJH came back to me, 559/549 both ways. I was running about 2W, he was running 3W.

I do have to fix the sidetone on the QCX as calling CQ sounds more like “thump-de-thump-thump-thump-thump-de-thump”. I have the new capacitors, but am waiting for some new BS170 transistors so I can hopefully up the power level to more like 4W too.

But the QCX is an amazing radio for the money and hey, I built it myself, complete with the case and custom label, so any QSO makes me smile.

Another 20m SSB session with the FT817 and I bagged Jack OH3GZ and Juha OH6QAZ.

At this point I packed away and after lunch headed for Beeston Bump on the coast near Sheringham. I’ve written about this before as it has a fantastic view over the North Sea.

Anyway, I put up the EFHW vertical for 20m and set to with 5W CW from my Elecraft K1. This raised Gert OH/DL7UG and Dima RW4C. I then bagged Fabi IK5IiS near Florence.

Also heard were stations in Cypus and Canada, but the Cyprus station on SSB couldn’t hear me and the Canadian seemed to be sending his life story in CW to another station and I got fed up waiting to call him!

I also had a play with my 3W MTR3, but didn’t work anyone as I could see rain clouds coming and decided to pack up.

So not a bad day’s radio. The Elecraft K1 and Yaesu FT-817 worked flawlessly. I think I was getting some RF into the keyer on the QCX as I had trouble sending “/P” – the “/” turned into a right mess sometimes, although I had no trouble sending it on the K1 with the same Palm Paddle.

The moral is that life is NOT too short for QRP!

Update: I checked the reverse beacon network last might and saw that I had been picked up across Europe while calling CQ, but often with no response. Some of these SNR figures are quite large too. In other words I was loud enough.

That's a shame as it would have been nice to have worked some more stations.

Is this because of a lack of activity? Or is it because, as I often wonder, that a lot of people have moved to FT8?

RSGB certificate for 5th place QRP section.

Update: It turns out I came 5th in the QRP section of the 2018 Commonwealth Contest. I lost two QSOs for being "not in log",  and lost 4th place by 10pts to Dave G3YMC (which is how it should be!). Great fun and I'll do it next year, probably with my Yaesu FT817 and the addition of an EFHW vertical for 20m too.

I took part in the 2018 Commonwealth Contest this weekend on HF CW. This was always going to be a casual entry as I had other things to get on with over the weekend, not least was helping tidy the house for Mothers’ Day on Sunday!

I decided to enter the QRP category with a maximum of 5W. One reason was I knew that my good friend Dave G3YMC had won the category last year with 30 QSOs. I mean, how hard can it be to beat 30 Qs with 5W? Answer: very hard apparently!

I got going with 20m and quickly worked four stations in Malta and Cyprus. I also cracked off some of the UK HQ stations on 80m for 25pts apiece.

The afternoon saw openings to Canada, which brought in a few VEs. I was also happy to work the Cayman Islands and G3TXF on Mauritius.

My multiband fan dipoles in the loft. Only used with QRP for EMC reasons.

Ionospheric propagation conditions were lousy with no sunspots and a geomagnetic disturbance the night before.  Fifteen metres was closed so it was a 80, 40 and 20m only event.

What you quickly realise is that many stations are using the full legal limit, so might be running 400-1,000W. If they aren’t very strong they probably won’t hear your 5W QRP station - fact of life!

So there were lots of “NR?” being sent for repeats, if they came back at all.

I went to bed about 23:30hrs and set to again at 06:45hrs. At that time 20m was dead, but there were some 40m and 80m contacts to be had and I managed to get VE in the log again. I also swept up the remaining G, GD, GI, GJ, GM and GW HQ stations as these were quite easy with 5W.

The antennas were my loft-mounted fan dipoles for 40-10m, which beat the outdoor multiband 80-10m end-fed half wave and W5GI dipole on 20m - go figure. I used the EFHW or W5GI for 40m and 80m, depending on which gave the best signal.

The “nearly” category included QSOs with Singapore, Australia, Gibraltar, New Zealand and Zambia - I just wasn’t loud enough. But hey, Cayman Islands, Canada, and Mauritius on 5W will do me!

Next year if I do it again with 5W I might put up a monoband 20m EFHW and perhaps use my Yaesu FT-817 (I don’t currently have a CAT cable for it), although the IC-756 Pro3 band scope is handy and it is an excellent rig, even when backed off to 5W. Logging/keying was with N1MM+, which worked flawlessly.

All good fun and 30 Qs won’t win it ( the highest QRP entry so far is C6AKT with 92 QSOs), but my unconfirmed overall score was higher than the 2017 winner’s, so not too shabby.

The Commonwealth Contest is a great one-weekend opportunity for UK stations to work DX with no big pileups.