Ultimate 3S - It Lives!

In between boxing up parcels, and scaring kids with my S10 respirator (in my defense it is Halloween!) ive had chance to power up and configure, partially, my Ultimate 3S beacon -

I had a few difficulties at first, due to a crocodile with a wide mouth! It turned out that the crocodile clip I was trying to use had been over stretched and its teeth didnt quite come together, so my -ve lead kept falling out!

It took some time for me to become familiar with the menus and the setting process. I managed to eventually get my callsign and locator set, and a WSPR mode transmission set up. I then had to go Trick or Treating with Tom,

These are the pumpkins I carved yesterday, suffering intense cramp in my hand as a result!

Back in the workshop, timing was set reasonably successfully using my watch. The power output was a doddle to set though, although my QRP power meter and dummy load isnt calibrated! I used my Alinco 2m handheld to calibrate it roughly, by measuring the handheld output on the Marconi 2955, and then seeing what that power read on the QRP meter. With the one BS170 MOSFET, it seems I am getting a comfortable 1/4W, or there abouts. Frequency was more awkward. For a start, I wasnt at all sure what to set! Luckily I discovered the table of sub-bands in the manual, and was able to set up for the center of the band. Then I managed to eventually find my signal on my main radio, which is acting as test receiver.

I eventually worked out, after a few false starts getting great decodes of my own spurii, that I was about 4kHz off frequency. Without the GPS module in use, I had to do a manual calibration. The instructions for this turned out to be in the assembly manual, not the operating manual!

My frequency is now roughly in the middle of the operating window. My own decodes are a bit intermittent at present which im putting down to having set the synthesiser to turn off between transmissions, which I think is causing a bit of a chirp! The 'park' control in the firmware is for telling the synth what to do between active transmissions, so I will set that back to an 'on' state.

The above screenshot shows my WSPR signal, and the recent decodes.

Before I can put the beacon to air though, I need to build a 5V regulator board for it, to allow me to run it from a 12V supply. This is a task for tomorrow.

Box Disappointment

Slightly put out today I'm afraid. Ive finally come today to testing the CRS L/R box I got as part of my order around a month ago from PTS. Unfortunately, theres a problem. The headset audio 'motorboats' and the control functions dont operate. Ive tested it with alternative cables to ensure it wasnt a wiring issue; on two different radios (different types, a 320 and a 350); and with different audio kit.

This is a real disappointment, but not a disaster. Ive emailed Graham at PTS about it, mainly to see if he can direct me to the necessary EMER in order to fault find and hopefully repair the unit. Ive also opened it up to check for any obvious issues, which gave me a bit of a shock as I wasnt expecting it to be anything like as complex as it is!

It is indeed beautifully made, but daunting! I really dont fancy taking it on without a schematic!

On the positive side though today, ive sold on quite a few of my excess PRC-349 batteries, and also the remaining excess PRC-349s! This has effectively covered my original costs, and raised me sufficient funds to progress a few other radio projects.

My list of projects that need completing though is still looooong! Ive made a start of restoring the Clansman hand generator, but thats just a bit of a lick of paint. My next two priority tasks are to test the Ultimate 3S beacon, and to complete the refurb of the PF8, now that I have the capacitors.

The various small modules are beginning to trickle in from the Far East now. The Arduino Mega has arrived, so Im in a position now to be able to start working out the control system for the PRC-320 Remote project. Im short of just the display module for the camera dew heater, with any luck that will come in the next week or so, so that should be finished and ready for the winters night photography.

WhiSPeRs in the night

Ive decided, as of 23:10 UTC, to run my 7MHz WSPR station at 15% Tx and 27dBm (thats 500mW) overnight, and see just where I hear and where hears me,

This is around about the sort of power i'll be setting the U3S up to run when its complete.

Rishworth UKBB RF Probe made permanent

Despite its simplicity, and that it was intended as a very quick to build, 'no-solder' project, I was so impressed by the neat little RF Probe kit supplied by Rex W1REX or QRPme for the G-QRP club Rishworth Conventions 'UKs Biggest Buildathon, that I decided to actually solder it!

I didnt want to tag solder to the IC socket, as I felt this would look untidy. So I took the drastic decision to remove the socket. Rather than struggle to desolder so many pins, I did this (may Rex forgive me!) destructively - by cutting away the body of the socket and then using a heat gun to melt the solder and allow me to knock out the pins.

The result is now a very neat permanent rebuild, which will eventually get a nice little round housing, a sharp probe, and some nice leads with 4mm plugs on them

I retained the original vertically mounted zero-ohm links, rather than replace these with wire links, so I can still use it as is, before it gets boxed up.

Release the Hydra!

It should be the Kraken, of course, but ive never found mythical sea monsters to be particularly useful in bulk charging batteries!

The Hydra in this case is a simple multi-headed trickle charging solution! Ive found that many deeply discharged batteries will recover, but the Accucel-8 cannot detect them! So, by sticking them on a 15v supply with a suitable series resistor, in this case 120 ohm, I can bring them back up to around 11-13v terminal voltage, and the charger will then detect them and go into the recovery cycle.

The 'Hydra' trickle charger!

With quite a lot to get through, I set up the 'Hydra' to allow me to bring up half a dozen or so batteries in one go.

Ive now run around a dozen through a pair of full Discharge/Charge cycles, and they all seem to have come up to sensible capacity. Around another 50 have passed basic on-load voltmeter testing and should recover when given the cycle charging. About a dozen have failed completely to recover at all

I can now at least dispose of all the known failures, and concentrate on those that show promise. As such, I am also now in a position to separate the 600mAh packs from the bulk of the 550mAh packs! I want to retain around ten good packs for my own use. All the rest can be sold on. Two lots of untested packs have been sold, thats 20 batteries. Im slowly clearing the space in the workshop!

Very kindly, one of the BVWS forum members, Tony, has sent me some 5p6 ceramic capacitors of the type I need to complete the PF8 refurbishment.

I shall get on to that shortly. It now requires some serious dismantling to change these capacitors, due to them being very close to the chassis edge.

The Ultimate 3S is coming along, slowly. Ive not yet heard from Hans regarding the missing inductor, but theres no rush. Ive completed the 10m LPF, this time without getting my wires crossed!

28MHz LPF, L1 (10t) fitted

28MHz LPF L1 and L3 installed and glued down

28MHz LPF complete

Ive also made up the RF coax connection header. This is using my TNC pigtail at present but will do for testing. I dont wish to power the unit for testing until I can have the output fed to a dummy load

RF coax header connection

Ive been hearing a lot recently about 'Parrot Repeaters', otherwise known as a Simplex Repeater, a type of Voice Store And Forward system. These are used on 70MHz where there is insufficient bandwidth for duplex repeaters, and generally seem to be much simpler to build. Im wondering if there is any such machine im my area, and if not, what the requirements would be for me to instigate one...

Chance of Aurora and no visibility

Past few nights have had lovely clear, starry skies, tonight theres a class G3 geomagnetic storm

and its bloody overcast again!

There seems to be a correlation between likelyhood of visible Aurora, and how bloody cloudy it is in the UK!

Ive done a slight bit of work on the Ultimate 3S today, such as making up the power cable and the cable to link the GPS module. Ive also ordered a BNC panel socket with coax pigtail in order to make the RF connection. The pads to connect are too small to safely solder coax to, even the very thin stuff I have, so ive added another pair of header pins. I can either solder direct to them, or put a plug on the coax. It will probably be a couple of weeks before the cable arrives, but in the meantime I can test using the only other coax pigtail I have that will fit, which is currently attached to the prototype Wispy project that I couldnt get to work for me. The reason im not just using this on the U3S is that the coax connector on it is a TNC!

I also need to find a suitable case for it! The U3S itself needs a metal box, ideally one that I can modify to accommodate the battery housing from a PRC-349, but then a plastic box will need to be attached onto the metal one to house the GPS unit. The plan being to make the whole thing completely portable - just attach antenna and switch on!

Ive just returned to 40m WSPR - as expected, the geomagnetic storm has pretty much wiped out HF propagation, but, there are a few spots to be had!

PRC-349 batteries for Ultimate 3S?

A thought has occurred to me - Whatever case I decide to build the Ultimate 3S beacon into, could I possibly modify it to include a housing the same as on the PRC-349, perhaps by actually sacrificing one of the '349 cases, so that the Ultimate 3S, once boxed, will take a PRC-349 battery as its power supply?

This would be a very convenient way of powering it in the field, and give me something to use some of these batteries in!

Ultimate 3S Beacon - Almost Complete

As well as charging batteries, and reading more Mark Twain, ive also done a little more work on the Ultimate 3S today,

Having built the main unit, the synthesiser, and most of the GPS unit, I pondered slowly along today with the Low Pass Filters. One small thing I noticed, which I may mention to Hans for a possible future improvement, is that there is no easy way to see what band a filter is built for! The underside of the PCB is all groundplane, and so I have marked the band on mine using a Sharpie pen, but from the component side theres no place to mark. Im not sure what the solution would be, perhaps an extra 1 or 2mm along the side of the board to give a writing space? or perhaps scratch boxes on the silkscreen for each band to mark?

Anyway, the first job way to fit the capacitors. These filters use a tried and tested design detailed on the G-QRP club website and in SPRAT, being 7-pole filters.

Some way of holding the tiny PCB steady is essential! Below is the 10m LPF having its capacitors soldered in place.

One problem with this build, which is fully appreciated and warned about by Hans in the paperwork, is getting the header pins aligned properly! My solution to this problem is to slip the pins into a piece of Veroboard prior to soldering

A bit of Veroboard helps align the header pins when soldering

After this came the task of winding the toroids. L2, the middle one, went just fine, 24 turns. But somehow the other two I managed to get the wrong 'handedness' to them - meaning the wires were on the wrong side of the toroid from the holes! Both had to be unwound and done again! And then, on one of them, I managed to get the turns crossed over and knotted!

But, after unwinding as far as the crossed section and rewinding, followed by some hard work getting the damn thing soldered back in, I finally have the 40m filter complete. A bit of hot-melt glue was used to secure the toroids in place.

The above photo shows my 'almost' complete Ultimate 3S Beacon, ready for 40m operation. The last task will be to make up a header plug to connect power, and to connect the RF out to a coax socket. I should have a coax tailed socket of some sort that will work for this. Another header cable, this time 4-way ribbon, will be made up to connect the GPS unit.

Clansman Battery Not Charging? Try This...

When I was refurbishing my first PRC-350, I had a small problem, in that no matter what I did I just couldnt get any power from the battery cassette. Eventually, after a lot of head scratching, I discovered that something was causing a very bad voltage drop when on load. This was eventually found to be due to corrosion building up under the battery contacts. Removing them, cleaning them up, and in this case replacing a rusty washer, sorted the problem out.

Fast forward to today, and I am somewhat lumbered with a great stack of old PRC-349 batteries. I cant shift these, because no one wants to buy untested and potentially no use batteries, even when offered at under 50p a go!

So, ive started cycling them all to find which are usable. The first problem I had was making a reliable contact to the batteries, croc clips have a tendency to spring off! Here one of the spare PRC-349 chassis came in handy. Stripped of all other parts and connectors, save the battery terminals, this can be easily connected to the charger by, at present croc clips, but soon by its own dedicated pair of 4mm plugs. The battery then screws in and makes perfect contact just as if being fitted for use in a radio.

Chassis turned into charge adapter

One problem that ive been having though, is that some batteries that are showing decent terminal voltage when tested with a meter, fail when attached to the charger. The Accucel-8 reports 'connection break', suggesting that it thinks the battery isnt connected.

After a bit of thought, I realised that in order to check the presence of a battery, the charger must sense current flow to or from it. Now, as for the PRC-350 battery cassette mentioned above, if the terminals are dirty, perhaps the resulting volts drop over the added resistance is causing the problem?

So I took one of the batteries that this morning reported 'connection break', and cleaned the outer surface of the terminals. One connecting to the charger it still reported a fault. So, not just the mating surfaces! So, I removed the terminals

and cleaned away any corrosion and dirt on the fixed terminals of the battery casing, and the underside of the spring terminals

A very crudded up terminal

This time, when connecting to the charger, the battery was detected! It is now on the second of a pair of Discharge/Charge cycles, and so far showing every sign of being a good usable battery!

Building the Ultimate 3S

Following on from the build of the Synth module yesterday, today ive done the majority of the construction of the QLG-1 GPS receiver module, and the Ultimate 3S Beacon transmitter itself,

First however, I had the faulty Clansman 10m Audio Extension to repair!

This was an absolute pig! The cores are tinsel wire, which gives the cable great flexibility, but makes repair really difficult. In order to rejoin the cores,I had to wire wrap them with solid tinned copper wire, but the size of the cable and the flexibility made it extremely hard to hold everything together while I did this, and then to solder it all together and sleeve the joins. But it is now repaired and tested as usable.

So, onto the Ultimate 3S. Building the QLG1 GPS module is remarkably simple, with very few leaded components to install. Unfortunately, my kit had two components missing. One, a 100nF dipped ceramic, I simply replaced with one from my own stock. But the other missing part is a 0.1uH axial inductor. I havent anything of this value nor even close to it. So ive had to drop the supplier a line asking for a replacement.

As the GPS module is not yet complete, I have deliberately not yet fitted the backup battery. It is just waiting on the inductor now and can then be powered and tested.

Building the 3S itself is a little more complex, as there are more parts to fit, and a higher density on the board, but still quite straightforward. The only thing that complicates it a bit is that the manual covers the controller build for three different projects, which leaves the builder to fathom out which links etc must be installed. I would have preferred the manual to have been more specific to the 3S build. But then again, theres still plenty of optional features in the 3S build to decide, such as whether to have software controlled LCD brightness (in my case yes), whether to soften the contrast control (yes), etc

The module can use its 5v supply to power the BS170 MOSFET PA stage, by adding a link, or the PA can be powered by a higher supply, for instance if fitting extra BS170s, without the link. As I want to use mine with the one installed transistor first and then add more later, and didnt fancy having to unsolder a wire link, ive been clever and fitted header pins and a removable link as used on PC motherboards. Ive also done this for the two links that hard wire the LPF module connections, as these links need to be removed if the relay switched band module is used, which I may wish to add later,

Im hoping alls well, but I wont be powering it up just yet. Im going to build one of the LPF modules first, so its all ready to test fully.