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Saturday 24 November 2018

BERU 2019 Where to go?

The search for the next DX location for the BERU contest is underway.

Choices choices... Africa, Caribbean  or Pacific. Plenty of DX in the Commonwealth list and more than a few have decent IOTA targets too.

Reviewing how few of DXped have done from various locations over the past few years.

Looks like will probably end up in the Pacific but as application to some can take a while dropped in licence applications for 5 locations also covering other regions. Shame but right now VQ9 seems impossible to get to for a civilian even though looks like licence would be granted. Got to watch issues with flights in an out of some places with all the radio kit as some authorities have changed the ease of transit lately.

I expect will be right by the sea, well equipped with 4 square and decent VDA etc. Dual KX3 will probably be used and will try the arduino based homebrew SO2R setup again. I will add SDR RX and WSPR to the mix as well as some ATS-3B and mcHF activity.

Depending on the location I expect the mid day RF blackspot I might fill with some satellite work (if applicable). FT-817 and a simple Arrow clone.

Interested to hear any suggestions (hopefully from those that have been there not just an armchair DX request)

Friday 23 November 2018

Several 4SQ comments and questions?

Since various blog posts and talks a few have asked me about construction of the 4 square antennas I use when DX, so to try and answer questions....posted here in no particular order are some of the questions and my comments:

Couple golden rules:
NEVER NEVER NEVER use a tuner with one of these!

NEVER NEVER NEVER switch direction when RF is 'hot'.

You have to know what I wanted these for... QRP DX trips, I say again QRP DX trips. So when I was DX to you, they should work fine the other way too but you need space (real estate) to build these and I have no idea what they will be like next to a house. They do NOT fit in a normal domestic back garden.

They HAD to work first time every time.

I had to be able to carry this ALL myself to a DX location and put it up. So far this has worked for 40m, 30m 20m and 17m and a 2el for 80m.

I am a QRP op but I made my controller so could handle power (hence the SJ2W boards) as one station on a trip I would 'borrow' had a big linear. In end never used more than 100W. The important bit of the controller was get the phase right and did that with 4 channel scope and junk box/bag of silver mica C and swapped values until got it right. Cable length inside and outside (especially) the box REALLY do matter. I grabbed some dual 6A PVC power cable and used that to make the windings, nothing special about the cable, had to be able to handle the power that would end up going through it..... I have a L meter that will go to nH and the value used was approx. I used a spreadsheet (see my blogsite) for the values. Seriously not rocket science, you use the typical formulae F=2 SQRT(LC) to make sure made it OK. In mine you are taking an input and splitting it to a 90, 180 and 270 output... so the LC network HAS to be right. I used T225B cores don't think it really matters.

To get it to work... easy (after working it out)... put LOW power RF in, sample the different ports (50 ohm dummy loads on them all) with an oscilloscope. You could use a power meter but you NEED to see the phase differences. At it's simplest using a 2ch scope you will see TWO signals depending which is which and you should see the phase difference... simple. Repeat for the other outputs. If they are NOT close to the 90,180,270 so the directions will be in/out of phase rework the windings and the capacitors you use, there really is no alternative. Get it all working at low THEN increase power, borrow power meters if you can and put them on the different ants unless you have homebrewed some kind of current sampling. Switch power off, swap directions, that will tell you how much power will be going to ant 1-4 based on the phase etc... if not equal or you have poorly made verticals you might get odd patterns and more seriously the dummy load might see way too much reverse power when select one ant or another. That equates to lost RF energy. Even with a KW going in and some care on construction mine saw less than 10W going to the dummy load. I put dummy my load in different box (see elsewhere on blog) so it could be cooled separately. Some just put it in the same enclosure, some use actual dummy loads I do not think it is important what is used as long as it matches the antennas load.

Noone seems to say this, maybe most assume builders will know as maybe obvious, the 'controller' is actually two LC circuits back to back AT the frequency of the verts so it is vital you don't build that for say 7.030 and then try and use at say 7.090 verticals, or worse use a tuner .... the word idiot doesn't even cover it. I have heard one guy built for 40m and then used a tuner and raved it worked on 80m, I am not going to comment. Likewise never never never switch with RF hot, I really don't care what relays you have, the contacts will get damaged. Don't ask how I know that one.... switching on RX fine, infact you will do that a lot once you learn how to use it.

My GP were built with heavy duty speaker wire (I think it was) also able to handle KW+ (remember the wire acts like a fuse too!) and all 4 were IDENTICAL... that is 110% vital, take time over making them, the performance of a 4 square antenna 110% relies on these! I used SOTABEAMS 10m travel poles as cheap and reliable and worked for me, the support doesn't really matter as long as not carbon fibre. You could (as many have) just use Aluminium tubing directly. The wire for mine I very wide spacing spirally wound about the poles so even in higher winds the wire doesn't flap about.

The feed lines between the verticals and the controller box is very very important. They are often called phasing lines. I used, lots of chats with Dave G4BUO was the most helpful in the area, was brand new CT100 TV sat coax with SOLID core, foam dielectric, foil and braid dual shielding and well able to take KW and it was 75 ohm (This matters as 50Ohm coax will be way too short for the feedlines at 1/4 wavelength separation, you will have to make them 3/4 wavelength long, will work just as well try it and see!).

Q: Can you get away with only a few radials

A: Not really. In C6AKT I used with 8 raised radials per verical and good have benefited from a lot more. The site was literally right by the shoreline too. You need 4 really good 1/4 GP antennas so focus on building those.

Q:  I was looking at your 4-SQ build pages. I am also building an SJ2W board for 80m, using T225A cores. My LCR meter is at the bottom of its range for the inductance required and it is +/- 0.5uH so it hardly worth using to make the toroids. May I ask how you made yours? Did you measure the inductance or just use the calculated number of windings and then tune with the Scope to make sure the phase of each output was correct?

A: See above. I measured the L on the cores before hand. If you do not have a meter and you have the cores from a good source perhaps use the calculators (google for them) to work out what the L value should be.

Q: Can you use variables for the C values?
A: I do not see why not but one big caveat is temperature variations will be a factor. Initially I used two variables and then switched with fixed values.

Q: I only have a two channel scope and am very inexperienced in using it. Do you know of a guide I could follow on how to tune a 4SQ set up?
A: see above for steps. You must be able to obtain a nice simple plot on the oscilloscope of the input signal (at very low power levels). If the timebase cannot cope with the signal frequency, borrow another one. You cannot do much if it will not.

Q: (more a statement really) I am somewhat afraid of putting too much RF into the Scope and letting the smoke out!

A: See above.

You can mess with that whole part without having the PCB or the antennas. Plenty just point to point wire it all anyway. There is some snake oil in that you CAN adjust the individual GP's for a different freq and use variations on the matching lines to get specific directions but seems far too far fetched for me. IF DX, there for a w/e, that cost £k's to get there you have not got hours to mess getting antennas to work

Q: Why do you bother isn't a simple dipole/endfed/random wire good enough as I made nnn qso from ?

A: Yes a dipole/enfed/random wire will work too to a degree but you have to understand why I wanted them. I built mine for RX directivity NOT TX gain. I'll say again RX not TX. RX >25dB F/B should be easy to obtain. I never cared about TX gain. When you are the DX, especially QRP, an oxymoron for most, you absolutely MUST be able to hear the other side and on LF a GP is great but frankly bugger all use if you need to be sure about one station in couple hundred calling you especially when 99 are at 59+40db and the one you want is 57 at best. The effect will be any QSO rate slows down big time.

I was just looking for RX directivity and came on this all by accident when in SM I had three verticals in a row for a contest on different bands and for fun after contest made a 3el 40m yagi... not for TX but RX. I played with spacing so I could hear the far DX location I wanted. The separation makes a huge difference to the signal F/B ratio and take off angle as sure many know. I made up some FT-114-43 transformers I think to measure the current in each antenna but in the end seemed fine.

Honestly I think chasing TX gain in antennas at HF is almost pointless for a DX op... Directivity and RX gain is where the major benefit is. I do go for the salt water gain though which seems like 3dB every time. That is why some of the top DXCC count guys don't really care about RF 400W, 100W or even 10W.... ask 'em about their antennas on RX. Ask any DXped why do they spend so much time on decent antennas for RX.

Q:That box I used a few times, (you will see in this blog) few have asked why not a metal one?  Where did you get it?
A: Well it was cheap (£5) and I bought a few. Made from ABS and clear top as was light weight, IP56, cheap, fitted the board etc and it was important did not mess with the RF when lid on. My 1st PCB version looked really professional in an old sweet tin but there was so much interaction it was hopeless. I got it from ebay I am sure most electrical wholesalers do IP56 outside enclosures it is one of those you want. DONOT use a dicast box for it.

Q:Will you ever make a 'kit' for someone to make this?

A:Not sure there is either enough in it for me or there are too many 100% homebrew designs out there now?

Q:Will a controller with smaller torroids work at QRP pwer levels

A:Almost certainly. I actually made one using point to point wiring, for 30m,  and T50-2 cores. There might be mileage in making up a PCB that will suit QRP.

Q:What do you use for the controller cable, when you need to switch directions.

A:It all depends what is doing the switching really. If 12V relays you need to be sure that 12V is actually getting to the relay (or you use a transistor circuit to pump up the voltage). To use in one direction or other, as the relays are not latching types, you need the voltage to keep the relays energized. This is NOT battery friendly! I expect you could make the control switching wifi based and use a remote (local to the controller) uPC board but I've not done it yet. Some have used 5V relay instead of 12V ones and 24V as long as the cables can handle the current and there is not too great a voltage drop. I use CAT5 for the first few after checking that I was getting 12V at the control end. Now I tend to use shielded caravan signal cable. REMEMBER this cable is in the RF field so it will (not could!) have induced currents in it.

Q: Can this be built for other frequencies?

A:Yes but you need to be aware that as you go up in frequency the factors related to significant attenuation in the transmision lines of the signals etc start to make this design much less effective. I wouldn't build one at 10m or 6m. I have built one for 15m.

The bible for 4 square for me is ON4UN book on LF but lot of his maths escapes me.I would love to find time to investigate the option of adding a 5th vertical, placed where the controller is but that is a different antenna.

Tuesday 25 September 2018

Clear out of valve gear

Well this started as just a query for where might be the best place to take stuff into a "I'd like that", "do you have one of these?" series of discussions and email pretty much got mobbed.

The R1155 has found a very good home and will be off to an RAF Museum where to be honest it belongs as it is part of our/their history. I am pretty sure this one was used on a launch which fished crews out of the North Sea.

The HRO-M I still have to find a home for it, this one was also marked as an R106 and did time as a VI set and I am aware it has provenance so this is not being just sold on.

Lots and lots of 60's and 70's era valve kit looks like will have a new home soon.

The 1920's and 1930's era valves for ARRL TNT etc (all old globe type valves) as well as a set of B2spyset valves will be off soon.

The Sussex valve tester will go too that looks like it has a good home as well.
A couple of new build parasets, using old components I have to figure out what state they are in. Lots of components as well.

I'll inventory what valve kit is left soon including all the relevant books etc. There are quite a few FT243, 10XJ et al crystals that I will find a home for.

Then will go through some of the more modern rigs, projects I have not really looked at for a while and quite a bit of test kit, so in the end I will have a much reduced shack/workshop. No not giving up the hobby just rationalizing stuff as I need the space as well.

Friday 7 September 2018

Dual Hotends on K8200

Going to see what this looks like on the old K8200 3D Printer a Chimera V6 dual head with remote bowden titans extruders will set it up for 3mm and 1.75mm. I have a feeling I might try some PVA dissolving filament as support material.  

0.2mm,0.3mm, 0.4mm and 0.5mm Nozzles for 1.75mm filament, also have some 1mm and 1.5mm for 3mm filament. Looks like the heaters can be either 12V or 24V and the thermistors are standard 100K NTC glass bead type.

I'll add a pair of silicon J6 clone socks to them as well so can differentiate between them.

The mount will almost certainly be an aluminum plate or 3D printeted backet.

Looks like RAMPS1.4 will happily accommodate the extra extruder and hot end.

The filament run out sensors will also be separate, not sure can have on both but will investigate.

Wednesday 5 September 2018

Fitted some longer arm microswitches to the Y axis of the PCB CNC

Set a job running, it was all running fine but found the CNC had happily reset it's origin after 1st PCB was milled (8 pcb on the same bit of PCB/FR4), As the shorter armed microswitch had not triggered when it was supposed to. The sacrificial table cover had been milled instead for the next 7. Oops.

So swapped out the Y axis micro switches for some longer arm ones instead.

Think I might look at 3D printer Raspberry Pi and Octoprint / Octolapse type functionality with a small camera so can catch issues. I think there is a Prontoneer Raspberry Pi CNC shield that is basically the same as the Arduino one but you aslo get the Raspberry Pi control.

Tuesday 28 August 2018

tinkercad to make mi0iou wobbulator enclosure

Not found one (must be one out there somewhere) but going to use tinkercad to design and enclosure for my old raspberry pi A based version.

See for details of the project

The boards approximately:

Will now create an box enclosure and then copy the boards onto it, but as a 'hole' so you get all the openings in the correct place.

Have gauge with me today so will measure those SMA connectors and the pots a bit better.

Saturday 25 August 2018

shack needs sorted out as had to move stuff to operate as had issue finding space!

Far too much stuff in there so in between qso for GQRP summer sizzler looking at what is in the shack and cleaning up a bit.

Over a years worth of older IT and Radio magazines can go, plus all the older QSL cards, as scanning them now.

Not sure about the piles of buro and clublog card requests where I said electronic only. Might just grab random card, stick on a label and send it back.

Thursday 23 August 2018


As coming into the winter months again and LF is dominating for a while going to improve the LF options a bit.

I had  used an IRF510 based PA based on with one of G3YXM/G0MRF's  transmitters. I had played with transverters using  10MHz/30m and not the more usual 10m/30MHz. Antenna was an inverted L.

The bench certainly had a Graham VK3XDK 472KHz transverter for KX3  completed but not in an enclosure so I will have to pull it all together again and finish it off.

I note previously I had used 22mm or 25mm, cannot remember which, white PVC conduits as the LPF coil foms. I see there are some nice 3D printed LPF coil forms for 472KHz available so will try to source the STL files and take a look.

Buddipole guy rig

Used my buddipole all over the place and one thing that is a major pain is if it is windy or is tugged over (later happens far too often) it can be a pain. I ofgten just attach the carry bag to the bottom of the tripole and fill it with sand/stones.

Anyway whilst looking for something else I found this: and thought THAT is exactly what I need.

He used BB gun pellets to allow the rotation which are 6mm diameter, pretty sure I have some steel ball bearings with the same diameter and as I cycle I have lots of lithium grease.

And it is of course in the correct colour for qrp.

My own print photos etc will go here:

The 6mm metal ball bearings have cleaned up nicely.
Now to look at that lithium grease.

CNC end stops

Since had a rethink after finding I had some nice (larger) micro switches so will build some locations and wire them in instead.

I see someone did this for their 1610 CNC and the parts are in thingiverse.

This is what I added:

After having fun drilling 2mm holes and using M2.5 hex head screws I did the same for the X stops and mounted the switches.

I set them up so the whole drill assemble when moved on the X axis towards an end stop will trigger it.

The Z switches I need slightly longer arms on the switches, or will have to add something to the bed to switch it. Procrastination time needed. Use slightly longer screws and lock nuts too.

I also added some nice new 8x5 bearing couplers too. The one on the Z axis looks fine for now but might take it apart and replace.

Tuesday 21 August 2018

3D scanner

As had a bit of fun trying to reverse engineer some parts for a ghost hunter (I am a not a believer!) I thought it would be fun to sort out a 3D scanner. So I have decided to make one. It might not be very good initially but I am sure I'll learn.

The idea is pretty simple really place an object in the field of view of the camera and then using vertical lasers slice the outline, capturing the laser profile/lines, turn the object and create a wire frame. I am sure it might be a tad noisy initially.

The parts all printed last night. after the parts all turned up from various places. Will be fun putting it together to test this w/e probably whilst operating during the GQRP Summer Sizzler will add a photo at the time.

Sunday 19 August 2018

End stops to CNC2418

Looks like will add some mechanical end stops to the CNC2418 used for milling PCB.

Have a few options but the simplest might be to use the RAMPS1.4 end stop modules from

Right now only got then one sided and need to probably pair these up. (or reverse that switch mount.

The locations for expected end stops will be

Wednesday 15 August 2018

Raspberry Pi and Octoprint

Just put the systems together... so will cnc own pcb and make cases and parts too.

Two Raspberry Pi 3 B+, 16GB SD, Pi Cameras, Wifi Cards for octoprint and octolapse.

Will print up cases and these will be one for the Creality Ender 3 and one for the K8200 the second will be in the shack.

I may add another Raspberry Pi 2 B+, 16GB SD but without a camera for the CNC2418 currently in the box if looks like can do that. I will print a 7" LCD mount for a 7" TFT I have for it.

The RAMPS 1.4 boards and bits are all here as is the Arduino CNC shield so I'll update them as well. The K8200 will be seeing some stepper motor updates as well as will add a 3D Touch (BL Touch clone), I have a 3ED V6 hot end clone, although it is for 1.75mm, I can try that until the 3mm one arrives. Got the setup can use direct or bowden feed, might try bowden with a sort of Robin 3D or a GT2 belt double sided extruder.
The ring LED illuminator I got a while back will be added, might have to still get a glass bed for the K8200.
The K8200 electrical contacts for the extruder and hot end there is an STL I need to print that will house a series of connector blocks instead of those nasty solder/heatsink bodges, as well as a few other options.

The Ender 3 will add the PetFang ducts and BL Touch. And a draw that fits to the left of the current controller. Might have to redo/reprint the filament feed that fits to the top as the plug had been damaged.
I have a 5V power supply and LED which were for the CNC but might emply them on the ender3 in the meantime.

Filament sensors will also get added using the end stops that came with the last RAMPS setup. Marlin Firmware will be recoded and configured for the RAMPS1.4I expect will push the buffers up a bit.

The insulated enclosure for ABS etc, I'll add to the K8200 but not sure will need it now as it will only print PLA, so will probably just use it as a cabinet for it.

Not that I expect fire problems but if going to run the printers remote. I will add/mount a MINI AFO Auto Fire Extinguisher Ball
above the printers, got the first one from Amazon the other day. £25 not exactly much to protect against fire. Already have a few dry powder extinguishers in the workshop and shack.

Sunday 12 August 2018

3mm under Z switch

Photo says it all. Everyone has some HSS drills this packet has nice handy dimensions on the pack too so you know what size you have used, although every drill bit will have it stamped on too.

Place a twist drill bit under the switch mount and then move the extruder mount GENTLY down (I did it manually with the steppers disengaged) and tighten in place so you can just remove the drill bit. Result is Z limit switch is c3mm higher.

You can tell it to move home and you'll see it will now be 3mm higher.

Friday 10 August 2018

Steppers on the K8200

For reference.

Will change these (one is burnt out anyway) for socket versions and change the wiring harness too. It might be worth investigating reducing to stepers with 0.9 degree rotation per step, 400 per revolution but that all depends on costs. I intend adding a second Z screw as well. These are also listed here 42BYGHW811
47.0 N·cm 3.1 V Ø 5 mm 1.8° 48 mm 2.5A 1.8 mH
about half way on the list

The current board is OK if a little old. Wouldn't support the second Z axis stepper anyway so has to be replaced. No idea why I never added heatsinks to the stepper motor driver boards.

I discovered I also had a new low profile NEMA 17 stepper, a clone (I think) Titan Aero and a clone all metal E3D V6 hot end (both for 3mm) but I like the idea of remote mounting the extruder to reduce the arm weight. Maybe will not have to if add a second one?

RSGB IOTA 2018 M1K EU011

Random collection of photos from camera

The bag pontoon, they pass the bags from SFerry, Scillonian III onto the other island boats, they all help so it goes pretty quick. The boats from ferry to right are for St Agnes (where I ended up), Bryher and St Martin's.

Base of the 30m and 40m vertical. The connections are to the little black potting box tie wrapped to the pole. The ground was rock hard so the screw at this point only went in a few inches.

So here is the fix... take the pole down (carefully), hand up screw the support in the ground, fill the hole with boiling water, wait 5 mins repeat, then put the screw back in, by hand , fit it with water (not boiling now), I used the wooden spoon handles and screwed the pole right in then as the ground is softer, put the pole back up.

You will need to guy it if it is windy, I had wind for just one direction so somewhat lazily added just a single guy to a cow sorter that was in same field.

The bench with ATS-3B and on 30m

The 80m vertical looks pretty good (is and QRPGuys 60m/80m vertical). I added 6 radials and used a short coiled length of 75ohm coax at the feed as a transmission line.

On 30m and as you can see NO internet.

Got the essential supplies. You can just see the WSPRlite and the fan I'll use later. All the necessary QRP colour of course.

And the power supply proved a handy place for the FANTA

Bloody rabbits liked the feeder so had to raise it.

Bye bye EU011

4SQ builds and big Yaesu rotator.

Got two SJ2W and 1 M1GEO 4 SQ controller to make up.

80m, 40m and 20m (I expect)

Will add to the 30m one I have already.

The dummy loads I have the one I made up, might make another.
For the controller cables should source some CAT5 and make them up.

The rotator, the plan is to ground mount it and rotate a c 20' TV pole onto which I'll add the 23cm yagi, will also be a mount for the DXhexbeam when using from home.

More Photos to follow.

Next big activity w/e is august bank holiday so need to make sure got inter-G working for that.

3D Printer/CNC reorg

K8200 (which I will be refurbing to RAMPS) I will keep as a 3mm filament printer. Will add Octoprint and OctoLapse to this one. Now gone to shack. Orange and Black PLA.

Creality Ender3 1.75mm filament looks like will become main 3D printer. A RAMPS upgrade is on the cards if need to as the current M/B is a bit limited. Got to add bootloader etc, after see that the power resume has been added to the Marlin/TH3D source, or just add it myself. I have a BLTouch but got a glass bed on the printer so might play with if this is worth it. Looks like have to make up the PETSFANG fan shroud. Got a few different nozzles to play with as well as a few different colour filaments.. Will add Octoprint and OctoLapse to this one.

Not tested ABS printing but might, all PLA for now.

The 2418 CNC that will make PCB easily enough is now on workshop shelf, it it's own sound proof box (it makes one heck of a lot of noise routing PCB!) need to finish the calibration after they sent a new motherboard, I have a feeling I'll update it to the Arduino CNC Shield.
Will add a version of Octoprint and OctoLapse to this one I think.

Will add photos bit later.

Found still had all the parts for another CNC engraver from an Instructables build. Not recommended now but as have it I suspect will build it at some point.