Monday, 6 December 2021

LEARNING PSK ON THE IC-7610

DATA MODES WITHOUT COMPUTERS

Being relatively new to the Amateur Radio hobby, I've never experimented with PSK or RTTY and I thought it was about time that I tried it - after all - experimentation is what this hobby is all about, isn't it??

Thankfully, the ICOM IC-7610 has a built-in Decoder for PSK & RTTY, so no computer is required. At the back of my mind I'd always linked software to operating these data modes and I've always felt that I've got enough on my plate without having to involve computers, software and drivers.



The IC-7610 can operate these modes without any PC involvement and thanks to its ability to connect a keyboard (wired or wireless), it's a doddle to just have a go! 

It was G4ILO's great enthusiasm for the mode which originally got me interested and I was very sad to hear that Julian passed away. Apparently, he'd been battling cancer for quite a while and finally succumbed to it 😒

Julian Moss - G4ILO - RIP
 
One of the things that I learned straight away from Julian's blog was to take great care not to transmit bad signals on PSK. InterModulation Distortion (IMD) was apparently a huge problem due to poor or careless operators transmitting very distorted signals which would wipe out other operators on the band and make it impossible to decode messages.

Measuring intermodulation distortion of course, is not an easy thing to do unless you have specialised equipment, so most operators just ‘ wing it ’ by dropping their ALC levels and hoping for the best.  Julian chose to invest in a very neat and affordable meter which gave clear indication of your station's IMD - KK7UQ's IMD METER!

These meters are pretty cheap and can be found on the secondhand market for around £50. I got mine on eBay - a bargain. Of course you don't need one of these, but it's good to know that you're running a clean station and not causing interference to others. That is, after all, part of our licensing conditions.

So the IMD Meter is super simple to install - there are no connections to your computer, radio, or even antenna. You just sit it in the shack, raise its built-in telescopic aerial and away you go!




After setup, any transmissions with unacceptable levels of distortion will result in a warning light, and audible tone and an informative readout on the display. It also has a Field Strength mode, so you can use it to sniff out RF in your shack or anywhere else. Now onto the actual operating procedures...

It's always difficult to go into a new mode of operating when you're brand new to the game. The very last thing I wanted to do (apart from transmit noisy signals) was to interrupt other people, annoy them with my rookie attempts and get flamed!

So I looked around the internet for some tips on how to start. Thankfully, there's some great advice out there for learning both PSK and RTTY.  It seems that PSK can be more of a chat environment, whereas RTTY appears to be made up of brief 599/73 type activity.  I might be wrong there, but that was my initial impression, so I might end up coming back here editing this paragraph, πŸ˜‚. In any case, I don’t think there’s a great deal of RTTY activity these days.

Anyway, I decided to start with PSK and the first thing to do was find out where the signals are to be found on the bands, so a quick trip to the RSGB BandPlans revealed the correct part of the spectrum to be tuning into for the digibands.

With the correct frequency range tuned in and the IC-7610’s decoder switched on (it’s visible in the Menu once you’re in PSK Mode), I started to watch the messages going backwards and forwards. It all seemed a little confusing at first and I wasn’t sure at which point I would be CQing or responding to a CQ. So I watched for a while and followed other people’s interactions and did my best to learn about the best operating practises in this mode.

So I started with the 20M band because that's where my EFHW antenna is most efficient. Tuning into 14.070.150 brought in a stream of messages between operators and it allowed me to get an idea of how people were using PSK and what sort of exchanges were favoured.

Following particular individuals, it soon became apparent that some operators liked to 'chinwag' just like on SSB, while others were less keen on that and simply wanted a short exchange for the log.

The other thing I'd have to learn about is all the abbreviations! I'm obviously familiar with most, but some I had to look up like KN and OM. My overall lack of knowledge of this mode led me to start off by responding to CQ's rather than me calling CQ. I usually do the same in FT8.

It's been a very enjoyable start to learning to use PSK and (like FT8,etc)  I'm sure it's going to be a regular mode of operation when the bands are quiet on SSB phone.

Common operating frequencies...

Amateur BandUSB Dial Frequency
160 metres

80 metres

40 metres

30 metres

20 metres

17 metres

15 metres

12 metres

10 metres

1838.150 kHz

3580.150 kHz

7040 kHz and up

10142.150 kHz

14070.150 kHz

18100.150 kHz

21080.150 kHz

24920.150 kHz

28120.150 kHz

If you're a newly licensed operator and have never tried PSK, give it a go! It can be fun.

73, Tom, M7MCQ.

Thursday, 2 December 2021

RURAL RADIO SILENCE

PLAYING IN THE TROUGH

In the last 3 months I've felt under a great deal of pressure at work and haven't had a day off (or even an hour) in the last 3 months! At weekends I've just felt too knackered or stressed to go out and relax.

So I eventually managed to get a couple of days off to get my head out of the work-pit. Thursday, Friday, Saturday and Sunday all to myself and considering the weather was unusually bright today, I decided to grab my rucksack and go for a walk in the TROUGH OF BOWLAND which is just under an hour away from my home.


 
It's a beautiful place which I know very well because I used to have a holiday home just around the corner from it. Because it's Winter and the days are short, I couldn't go to some of my preferred (higher) locations, so I had to stay relatively low.

If you've never walked around the Forest of Bowland, you really must do something to change that - it's a stunning place, offering something for everyone, including families with kids. Needless to say, it's great for dogs too, but they must be kept on a leash - there's lots of wildlife and livestock around.



After stopping for a hot drink and breakfast sandwich at a well known Chuck Wagon in the Trough, I started my walk and pretty soon I was setting up my station which consisted of the ICOM IC-705 and a SotaBeams EFHW with counterpoise. I also had an Elecraft T1 ATU with me.


 
By the time I got set up, it was incredibly cold and there was a steady wind that kept the temperature low. Brrrrrrr! Of course, like an idiot, I forgot my gloves, so it was all very uncomfortable.

Switching on the radio warmed my heart though, because the noise level was on the floor. Almost silence!! Spinning the dial found loud, clear signals straight away. They weren't particularly strong, but boy, were they clear. I made SSB contacts into Europe, Russia, and Canada. I was going to play some FT8 but my fingers were FREEZING! So I closed shop and headed back home with heated seats on the highest setting πŸ˜‚

Had a fabulous day and it was much needed!

Thanks for visiting.

73, Tom, M7MCQ.

Saturday, 27 November 2021

QRP-LABS QDX KIT (BUILD)

A BEGINNER
BUILDING THE QDX KIT

When the QRP-Labs website went live with the sale of the long awaited QDX, I was there, mouse in hand waiting to add one to the Shopping Cart, but to my amazement, the Cart told me that the product was Out Of Stock even though it had only just come online! I believe they had around 400 units and they all sold immediately. I was gutted!


 
To make matters worse, one of the chips on the PCB was no longer readily available, so QRP-Labs would have to try and source an alternative before they could get some more QDX's manufactured - and how long would that take?? Some people were saying that it could be months πŸ˜“

Two of my radio-club friends had been fortunate to have secured their purchase and it wasn't long before the kits dropped through their letterbox. In no time at all, one of them built his and had it up and running. The other guy decided he simply had too many things going on to build his kit - and sold it to me - hooray!! 

I was so pleased about this because I really fancied not just the product, but the building of the kit too. I'd previously built a little Transistor Radio Kit by Tecsun and found it to be a great little weekend project. The idea of building something a bit more technical (not to mention more useful) was very appealing.

So I will use this post as a brief BUILD LOG. I'm not going to go into every detail because there's some excellent Video Logs on YouTube which are far more advanced than anything I could ever do. My take on things will be about how easy (or not) the kit is to build from a beginners point of view. 

I'll highlight any hurdles and point out any pitfalls. I might even end up pointing out how everything went pear-shaped πŸ˜‚πŸ˜‚πŸ˜‚. Fingers crossed it goes well.

_____________________________


The manual for the QRP-Labs QDX Kit is a staggering 105 pages long but only the first 37 pages are related to the actual build. Following that is a really good section guiding you into the actual operation of the QDX with software such as WSJT-X. The remainder of the manual goes into great detail about the design of the product, which was way over my head!


 
After checking the inventory to make sure you have all the parts available in the kit, the build is split into 14 sections and starts with the installation of the ceramic capacitors. Each part of the build looks quite straightforward but I must admit to being a little apprehensive about winding all those toroids for the Transformer, Inductors and Filters. Something I've never done!



There's one other part that I'm really nervous about πŸ˜•and that's the task of removing four Surface Mount Devices which QRP-Labs discovered were causing problems in the HF region due to self-resonances (after manufacture). These four miniscule inductors have to be physically removed (by desoldering) and replaced with four new ones supplied in the kit. The tiny pads on which the SMD's sit, are incredibly easy to damage 😬.  To be totally frank, I was really disappointed to learn of this problem and I believe QRP-Labs should have made it very clear that the end-user had to tackle a job which would not normally be expected in kits of this nature. SMD stuff is very tricky to handle!

The replacement parts are thru-hole components. It would be a real challenge for a beginner like me to work at SMD level, so I opted to get a friend (G4HYG of Cross Country Wireless) to do it for me so that I could relax and enjoy the rest of the kit. 


Have a browse on the website
 
Chris is a professional constructor of radio equipment and told me that he considers this QDX unit to be for Advanced builders because of the toroids, let alone the SMD work! He advised me to make the whole kit and then pass it to him to remove the 4 SMD inductors and run a Lab test to make sure I'd done everything right.

Looking around in the various forums and groups, I could see that quite a few people were having issues with failed output transistors and even the total death of the QDX. Reading between the lines, I could see that some of these failures might be attributed to the constructors choosing high input-voltage. Many people wanted the convenience of being able to use their standard 13.8V supplies and this results in a much higher power output than is recommended (potentially up to 8W), so I decided to go for the standard 9V input with up to 5W. 

So, onto the kit. Well the first thing that smacks you in the face is the minute sizes involved! In the past I’ve built a small transistor radio kit and that was pretty compact, but the big difference here is the toroids - they’re absolutely tiny!!

5pence piece!!

 
I’d been watching some videos of people winding these things but hadn’t really noticed their diminutive dimensions, probably because they had been using a large magnifier. Well now I can see them in the flesh and I’m more anxious than before πŸ˜‚πŸ˜‚πŸ˜‚

Anyway, I’m going to follow the Manual to the letter and that starts with fitting the Capacitors, followed by the Diodes, Transistors and then the TCXO board. After fitting anything I recommend ticking it off in the manual. Same goes for any testing that you're asked to do. Tick it off and you'll not miss anything.


With that done. it's time to do the T1 Transformer. I wasn't 100% confident with this but hopefully I've done it right πŸ™…



According to the manual, the next step is the Tapped Inductor L12, 

BUT STOP FOR A MOMENT!! 

If you are a beginner to all this kit-building and in particular, winding toroids, I would strongly advise you to hold back on the L12 for a few minutes and pre-build the other toroids, L14, L2, L3, L4, L6, L7 and L10.

Why?? Because these other toroids are super simple to wind and it will be good practise before starting L12, which has 3 loops in it (taps) and it's easy to get things wrong (like I initially did).

DO NOT INSTALL the other toroids, but just build them up ready for use later and be sure to mark them with a bit of masking tape before putting them aside.

 

You can see in the above example (L10) that this toroid has 13 turns as counted from the CENTRE. The "FIRST TURN" is the one on the right and it is counted anti-clockwise. 

Okay, so now that you're much more comfortable winding toroids, you can start the bigger L12 feeling like you've got some experience behind you. The only difference here is that you will need to put three loops in at varying points in the winding process. I would recommend watching a video by someone called MISCDOTGEEK.

Remember to count your turns VERY VERY carefully! And remember too, that the loop goes BETWEEN the turn-numbers mentioned in the manual, so for example, as you have just completed turn 19, form a loop and then carry on with turn 20. The loop itself is not a turn!

Below is a simple example I've made up showing how a 6-TURN toroid with a Tap between 3 & 4 would look. Note how the winding starts on the left at the TOP of the toroid and ends at the bottom.



I'd like to give you a couple of tips... When you've wound the L12 Tapped Inductor and are feeling proud of yourself because you've checked it over and over and are 100% confident that it's perfect, just stop a minute and do yourself a BIG favour!

Get a Hot-Glue Gun and neatly fill the centre of the donut and give it a few minutes to cool. This will prevent the wire turns moving around as you wrestle with the toroid as you try to get all 5 termination points into the holes on the PCB. Without this, it is incredibly easy to get wires crossed over and out of alignment (I'm speaking from experience)!

It's still easy to get movement of wires on the outside of the toroid, but at least you don't have to worry about the inside wires.  When you've finished the L12 Inductor, carry on following the manual - including the continuity tests on Pg.24.

The second tip is to forget the advice in the manual about burning off the enamel with your soldering iron or using the side-cutter method. No disrespect, but beginners are very likely to do some damage with either method in my opinion. It's better to scrape the enamel off with a sharp scalpel. 

The next toroid to do is the T2 Trifilar which is super simple but you need to twist 3 lengths of wire together as one before doing the winding. The manual suggests using a couple of little screwdrivers to do the twisting but believe me, it's far easier to use a small, variable-speed drill. Put one end of the three wires into the drill-chuck and hold the other end of the wires taught with a pair of pliers and then SLOWLY rotate the drill. Make sure there's a nice neat row of twists and no kinks! 


 
With all the toroids installed, I would suggest using the Hot Glue Gun to help keep them all in place. Without it, they'll be quite wobbly and prone to possible damage from knocks (even when in the case).


That's it! All the other components are very simple to install and are well within the capabilities of a beginner (if you pay close attention to the information in the manual). Needless to say, the replacement of the SMD Inductors is ridiculously difficult for a beginner, so you should either seek professional help as I did, or wait for the second batch of kits which will have the correct inductors pre-installed (and the TXCO).



UPDATE : Chris G4HYG  replaced the tiny inductors and a few minutes ago I collected it from him. He had put the radio through its paces in his Lab and it was pushing out a solid 5W on all bands!

He also tested it in action on FT8 and reported that the 30M band sensitivity seemed slightly low but he still managed to make contacts as far away as Kazakhstan, so it's not that bad! He said it was a "Little DX machine". So my thanks to Chris for doing the SMD bits and the testing. He also tested the unit on 60M but that's a band I'm not allowed to use as an M7.


All that was left to do now was to fit the unit into its box and screw it together. Just in case the transistors started to get hot with lengthy FT8 use, I drilled a set of ventilation holes in the case, top and bottom. I very much doubt that they're going to be needed, but it costs nothing to ventilate the box does it? I could always sit the QDX on top of my Yaesu Cooler πŸ₯Ά πŸ˜‚




REAL LIFE RESULTS:

As a real measure of the QDX, I decided to connect it to my SotaBeams BandHopper which I'd temporarily installed in the back garden. It was setup in 40M mode which was just as well because I can only test during the evening times due to work commitments. 

Although the BandHopper is supposedly resonant on 40M, the SWR is still slightly higher than I'd like down at 7.074MHz so I put the Elecraft T1 ATU inline to fine-tune the antenna and give the little transceiver an easy time.

I plan to try it on an indoor Magnetic Loop later and I'll have to pre-tune the loop using another radio (probably the IC-705) to make sure it's spot on before connecting the QDX to it.

To power the radio, I used a battery which I'd purchased specifically for the QDX. It's a 7.4V Lipo with a 5,000mAh rating. That should give me a good few hours use out in the field! For home use I've got a small mains 2A PSU putting out 9V. I was pleased to see that the PSU added no noise.

7.4V LIPO

Setting up the QDX for WSJT-X was pretty straightforward and there's more than enough information in the User Manual to guide you through it if you've never used the software before. The only thing I don't like about this transceiver is that you can't reduce the power output - not even by using the Power-Slider in WSJT-X. That's a shame really, because I'd have liked to have the option to drop power right down into the mW range for experimenting with antennas and such like.

As soon as I configured the radio in WSJT-X, the signals started to come in. The only issue I noticed was that the receive-signal seemed very low on the meter, barely getting above 2 or 3dB. I decided to move into the shack and connect the QDX to my EFHW which was better located.

 
Sadly, the EFHW made no improvement and the sensitivity remained low on all bands. Nevertheless, those signals kept coming in and contacts were easily made using 3W that the 7V battery provided! The majority of which came back with very good reports for me!


I've written a post on the QRP-Labs User Group to see if anyone can suggest why my signal seems down and hopefully they can make a suggestion as to why it may be so and how I can improve it.

Anyway, I'm just impressed that it even works! πŸ˜‚πŸ˜‚πŸ˜‚

I'll update again later.

73, Tom, M7MCQ.


UPDATE : Just found out that the Audio Gain can be adjusted using a Terminal Emulator, so I'll download one and increase the gain. Sorted!! πŸ‘ 




UPDATE : HORROR: 2nd Dec 2021  - I made a right bugger of things today. I connected the QDX to my main PSU having turned it down to from 13.8V  to  9V. But I forgot to set the switch at the back which tells the PSU to take notice of the front voltage dial πŸ™„

So instead of 9V, I sent almost 14V into the QDX which resulted in magic smoke from one of the four transistors. I quickly disconnected the power lead before any further damage occurred. So, so annoyed!!! 😑😑😑😑

Anyway, I inspected the QDX pcb with a magnifier and could see no evidence of damage to any component other than the single transistor. Luckily, I had spare transistors (after reading so many stories of people blowing them, I ordered spares), so I replaced the damaged tranny and plugged it back in.

Everything lit up as normal and it transmitted a full 5W into a dummy load with no issues so things were looking good. Unfortunately, when I plugged in the USB lead, Windows gave me an error, saying that it was unrecognised.

I found out that if I left the USB lead connected and restarted the QDX, the device showed up as the usual COM12 in Device Manager. WSJT-X found the QDX (including the audio drivers) and the two communicated perfectly well.

BUT, the receive signal was very low on all bands (in the red). Even raising the audio levels in Terminal Mode From 5000 to 10000 (and higher) only just got me in the green. No amount of trying would get a contact and the WSJT-X waterfall just looked ‘dirty’ and not at all like it normally does (full of bright red Europeans using 200W πŸ˜‚).

So it looks like I’ve buggered up more than the transistor 😭

UPDATE : 4th Dec 2021  - With a LOT of help from the QRP-LABS GROUP IO (especially from G4FZQ, AC9TU, SL6LKM and others) I have managed to get the QDX running again.  I replaced the burned-out transistor and plugged it in - it produced a nice clean 5W output with 9V in, so that was quite a relief!  

But then I discovered that the radio was not receiving properly and eventually found that it was (as G4FZQ suggested) was L12 multi-tap inductor. So I heated up the terminals to make sure I didn't have any bad solder joints and hey presto - I got 20, 30 & 40M working, but no 80 yet. I may remove the L12 toroid altogether and redo it, but for now I'll stick with the two I've got.

THIS MINI DISASTER was a result of a stupid PSU mistake and does not reflect on the kit at all - or it's suitability for relative beginners. It was originally working superbly so don't let this put you off if you were thinking of trying the QDX Kit.

73, Tom, M7MCQ.



Tuesday, 23 November 2021

TINY ELECTRONICS SHOPS

AKIHABARA HEAVEN

I saw a photo on QRZ.NOW which made me smile. Some photos just do that to you and you probably can't even explain why! Anyway, I discovered that this tiny little electronics store was in Tokyo - a place called Akihabara. I now want to go there πŸ˜‚

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A quick Google revealed a few others in the area. This is one of the reasons that I simply must visit Japan before I die! Everything is crammed into tiny spaces and the place is bursting with colour and urban vibrancy.

And yet it also has so much natural beauty too. Hmmm, I'm saving up to go!










Thursday, 11 November 2021

IC-7610 EXTERNAL KEYPAD

EXTERNAL KEYPAD
FOR VOICE/CW MEMORIES

DIY EXTERNAL KEYPAD IC-7610 /  IC-705

All the latest Icom SDR transceivers have the facility to store a number of brief VOICE, CW, PSK or RTTY recordings to re-transmit at the push of an onscreen button. The biggest benefit of this facility is when you're participating in a competition and don't want to keep repeating your CQ Call over and over into a mic or through a key.


 
Depending on the mode you are in, a different set of buttons appear on screen. You may choose to record different messages in there such as...

T1... CQ CONTEST CQ CONTEST, THIS IS M7MCQ CALLING CQ AND STANDING BY

T2... CQ 20 CQ 20 CQ 20 THIS IS M7MCQ CALLING CQ AND STANDING BY

T3... CQ 17 CQ 17 CQ 17 THIS IS M7MCQ CALLING CQ AND STANDING BY

You get the idea! πŸ˜‚ Pressing the on-screen button transmits the message once, but if you hold the button for a second, the transmission will go into a loop with a predetermined pause inbetween transmissions.

It's a great facility but the buttons take up a lot of screen space which makes your waterfall virtually redundant. The way around this is to buy or build an external 8-Button KeyPad that you can use instead of the screen buttons.  Such a keypad can be connected to a 3.5mm stereo socket on the back of the radio marked EXT KEYPAD. 

I decided to make my own keypad and ordered a suitable enclosure and buttons from an eBay seller. I also ordered a few resistors (values listed at end of the post). They were super cheap and quick to arrive. 

Now there's an advantage and a drawback to choosing a small enclosure - a small one will look real neat and will occupy very little space on your desktop (a big issue in my tiny shack). The disadvantage of a small case is that there is no room for any sort of labelling, so you pretty much have to remember what is stored in each of the 8 buttons.

That's not a massive issue for me because I have a small laminated card pinned to the wall, showing what's stored where. Once I've used the KeyPad for a couple of weeks, I'll no doubt edit it. 


 
Construction : The first job was to drill the 8 holes in the lid of the enclosure to match the diameter of the switches - 12mm in my case. I had chosen these particular buttons because I liked their domed appearance and the colour-coding. Initially, I tried a 12mm drill bit which immediately ripped into the lid and damaged it. Luckily, I'd bought two enclosures so I got out the other lid and this time I used a cone-cutter (often referred to as a step-drill-bit). This worked superbly.

The only thing I did wrong, was to drill by hand! I should have used a pillar drill because although I thought I was controlling it perfectly, it turned out that the drill bit was moving slightly and as a result, the buttons are not perfectly spaced 😑. Ah well, I know for the next time.



Once drilled, it was a simple case of fitting all the buttons, being careful to align the terminals in a way that assisted the insertion of the resistors. The circuit diagram is listed in the Basic Manual of the IC-7610 (Section 13-4) and it's very easy to understand even for a dummy like me...

Circuit diagram for the IC-7610

I was going to leave out that ninth switch (shown on the left of the diagram) - it's there to act as a Mute button and I just didn't think it was useful enough to include, but in the end I chose to tag it onto the end of the enclosure. CAUTION: I noticed in the IC-705 diagram, it does not have the mute facility, so if you're building this external keypad for that radio alone, it's best to leave it out (although I'm not really sure what would happen if you left it in and pressed it) πŸ’₯πŸ’₯

And if you wish to make one of these for the IC-7300, then you only need to make half of the circuit, since the 7300 only has four memory buttons. The connection to the radio is via the Mic connector (much less convenient)...


 
As you can see from the images, it's just a case of connecting one side of each bank of switches with the correct value resistor and the other side with a continuous connecting wire. Then you simply connect up the wires directly to the jack plug or (as I preferred) to a 3.5mm socket.  Because the small socket was reliant on a very small ring-nut to hold it in place, I decided to provide additional stability with a Hot Glue Gun just to be on the safe side. 

>>> NOTE THE MISTAKE <<<
The red wire is soldered on the wrong side of the switch
which resulted in an inoperative unit, LOL.
Quick swap-over sorted it out.

Putting the resistors in place made me realise that the case was indeed very compact! There was little room for the last two (the 1.5Ks) so I had no choice but to bend them back on themselves and locate them in the centre of the switches. Since there was no reference to the required wattage in the circuit diagram, I bought 2W resistors and I could probably have got away with much smaller 0.5W instead 😳. 

I'm not very good at this sort of stuff, but it worked out in the end anyway. The rest of the job is very simple and straightforward and the end result looks pretty good. I just might do another one to keep in my IC-705 rucksack (and this time I'll drill correctly and use small resistors).






This was a very simple little project which was fun to make and is a very useful addition to the shack.

Thanks for visiting the Blog. Feel free to leave a comment below.

73, Tom, M7MCQ.


COMPONENT LIST

4 X 1.5Kohm  +/-5%

2 X 2.2Kohm  +/-5%

2 X 4.7Kohm  +/-5%

1 x 3.5mm Stereo Socket

1 X 12V Latching Push Button (optional mute switch)

8 X 12V Momentary Push Buttons (whatever you have)

1 x Enclosure Box (100x51x22mm is what I used)