Saturday, June 24, 2017

First 4m QSO - getting a transverter kit working

Almost a year ago I bought a 4m transverter kit from DF2FQ (XV4-40). I have basic understanding of electronics, acquired in part through the hobby but building a project like this was new to me. With my mechanical engineering background I am more confident in building robust stuff like antennas, masts, supports, baluns, etc. Soldering loads of tiny components on a board seemed challenging. 

However the level of documentation provided by DF2FQ and some motivating words by PG8M - who was already using the transverter - pushed me to the point that I ordered the kit. When I received the package I must admit it looked daunting. 

Lots of parts..
..and rather tiny

I started building the kit sometime in August last year. I tried to work as meticulous as I could (a challenge when you are as impatient as I am). When I had completed the kit and ran the first tests, I found that I received 70 Mhz signals with the radio tuned to 29Mhz. Hurray!

However, when I tried to transmit, the transverter appeared to be dead as a dodo. No LED, no signal. A very disappointing result. I did some tests (as far my knowledge goes) and could not find the cause of the failure. So the kit went back in the box it was shipped in. Time for other projects.

The Es season is rather good this year and I have enjoyed the effects on 6m but 4m was open a lot of times as well. I really had to get back to the abandoned transverter project. PG8M had already kindly offered to help me months ago and today I took him up on his offer. We went through the error checking process step by step, finding and fixing four major issues. It turned out I had made two soldering errors and two of the smd resistors were faulty. Whatever happened to these resistors I really don't know.

PG8M trying to locate the next error

The good news is that we ended up with a transverter that delivered up to 35W on 4m with 5W drive on 10m. 

There was no one around to do an on air test so back home I hooked up the transverter and put my tri-band yagi on a pole @2m high in the garden. PG8M was QRV 30km away with his 4 ele beam pointing in my direction. That is when I made my first 4m QSO.

DK7ZB tri-band beam in action twice this week

It is a bit late in the Es season but I am sure I will get back to this band in the future. The next thing I need is an antenna I can set up quickly at home in case of any high MUF situations. For 6m I use an end fed wire that I can attach to a pole that I push through the attic window. For 4m I am going to try a slim jim vertical. More on that later.

Friday, June 23, 2017

Playing with 6m Es - compact beam versus vertical

Some time ago I built a compact beam for 6/4/2m aimed at /P operations. It is a design by DK7ZB featuring 3 elements on 2m, 2 elements on 4m and 2 elements on 6m. I tested it when I finished building it and SWR was good on all bands.

I followed the design of DK7ZB (link) with a few changes to make this a /P antenna:
  • I use wing nuts on the 4m elements and the 6m reflector to be able to remove them easily for transport
  • I split the 6m driven dipole in a short center piece connected to the boom and removable parts on both ends of the dipole
  • I added spacers for the dipoles to keep them at the right distance from each other (refer to picture below)
Spacer for the dipole elements

Apart from a short appearance in LX (2 QSOs), I had not used the beam on the air. For 6m I use an end fed half wave vertically - both when I am /P as well as at home.
It is amazing how effective a vertical wire is in Es conditions. I have worked stations all over Europe with that antenna using 100w. I was curious how the beam would perform in comparison.

We are in the Es season at the moment and there was a 6m contest on last weekend. So I decided to go out /P and test the beam properly against the end fed wire. I used one of my Spiderbeam poles with the end fed wire in the top (feedpoint about 12m high) and the beam a bit lower at about 8m high.

I used an antenna switch to be able to quickly switch between the two antennas. You need quick switching as the signals themselves vary constantly under Es conditions. The difference was significant most of the time. Of course the heading of the beam is a factor that influences the difference. With the beam heading the right way, the signal strength on rx differed multiple s-points. On the low end this meant there were stations I could only copy on the beam. I recorded a view video's while switching between the antennas. One of them is on YouTube:

With PG8M - who lives just under 30km from where I was /P - I tested the characteristics of the beam via ground wave. We found a difference of 2 s-points front to back and 5 s-points front to side.

All in all this shows me that this beam is definitely an interesting antenna to use in the field for 6m. It is light, easy to set up and relatively easy to transport. As the 6m reflector is rather long for easy transportation I am thinking of splitting the reflector in two or three parts.

While I was testing this setup I logged 25 stations, collecting 10 new grid squares on the go.

Sunday, May 14, 2017

Projects - Inverted V antennas for the low(er) bands

Choosing a /P antenna for 80m

My favourite antenna when working /P is the end fed half wave, set up vertically. It is easy to set up and works well with reasonable DX performance. It will not beat my portable hexbeam when working DX but that one requires more time, material and open space to set up.

The EFHW vertical becomes a challenge however on the lower bands. Now I did get myself the largest Spiderbeam pole - so a vertical half wave for 40m is an option - but there is a limit and 80m will definitely not fit.

One option then is to use a quarterwave vertical. However this requires radials if you want the majority of your signal to be radiated above ground. I developed a quarter wave for 80m with four elevated radials and it works but is quite a hassle to set up. Working /P you don't always have room for four elevated radials.

Another option is to use the EFHW sloping. That is a good option and I have used it on numerous occasions. If the support is tall enough to allow for an angle around 45 degrees the antenna still has a low angle of radiation but also a lobe at a high angle. That makes it a versatile antenna. It has some directivity - in the direction of the slope. 

The challenge on 80m is that the EFHW sloping still requires a tall support for a reasonable (steep) sloping angle otherwise you will end up with only the high angle radiation. 

Inverted V antenna

Another option - using a single support - is to use an inverted V dipole antenna. For 80m I find it a convenient antenna to set up and it comes with a unidirectional radiation pattern (in the horizontal plane) that fits my needs when I am "being chased" with chasers from all directions.
The inverted V has a high angle of radiation. On my 18m pole it very much resembles a sloping half wave dipole of the same length. The main difference is that the sloping wire will have 6dB F/B ratio while the inverted V is omnidirectional. It is very much up to what you are looking for.

Practically when working on 60m or 80m (or 160m) - for more than a few QSOs - I choose the inverted V antenna. When my tallest support still was only 12m I also chose the inverted V as my default antenna for 40m.  

For my inverted V antennas I developed a universal center connector that fits on the fiberglass poles I use. It is a simple component made from 40mm PVC that allows me to connect various wires to a SO-239 connector. The reason I designed it with changeable wires is that it allows me to make different combinations like 40m and 80m inverted V's on one pole fed by one coax cable. 

The tie wraps on the sides are used to keep the cable tension away from the soldered cable shoes - otherwise the shoe will certainly break in due course. The hole through the center allows it to slip over the top segment of my fiberglass poles.

I developed a couple of these center connectors so I can set up different antennas at the same time. We use them for example with the YNOMY DX Group during the PACC contest when we set up three different inverted V's (40/80/160). We then have the 80m and 160m on the tallest mast together, being fed from one coax cable.

For each inverted V I have two separate dipole legs. Each dipole leg is cut to the right size and features a cable shoe as visible in the first picture. To hold the wire I have constructed a cable spool consisting of a piece of PVC (40mm) with two end caps. On each end caps I have glued a piece of wood and through the end caps and wood I have put a piece of threaded wire. 

40m wire spool (one leg)
This spool holds the antenna wire plus a long enough end of tension string. I find it works rather conveniently in that I can just stick the spool in the ground (slightly under an angle) where it unreels while I extend the mast. Once I am happy with the position of the mast and antenna I push the spool further into the ground, stopping it from turning. This way I do not need pegs or anything else to set up this antenna. 

Below you see an impression of the antenna with four legs - dipoles for 80m and 160m - ready to be deployed.

I just stick the spools in the ground in the direction I want the leg to go. Then I extend the fiberglass pole with the spools unreeling until the mast is fully extended. Then I pick up each spool and place it where I want the end point to be. The advantage of the spool unreeling is that there is only a slim chance the legs get entangled even when you have two dipoles on one mast - the wires are kept under some tension the whole time. 

Sunday, May 7, 2017

Projects - 18m pole set-up improvements

I use a variety of antennas and poles/masts when /P. The 12m HD Spiderbeam is the most compact one I have and is easy to set up in the field without any supporting structures. The bigger ones I normally attach to the car one way or another or to any suitable construction I can find around the place I am going to be active from. My favourite and most versatile antenna pole is the Spiderbeam 18 HD fiberglass pole. I use it almost every /P activity. Preparing for a tour through LX I decided to implement some improvements that make the pole even more portable.

Guying the 18m Spiderbeam pole
I have twice set up the 18m HD Spiderbeam pole on my own using an ingenious structure with all the 6 guy lines extending while I pushed out the segments. That took quite a bit of time so I looked for another option. When I set up the pole using the car or a supporting structure I find that I do not use any of the supplied guy lines - so it should be possible to find a much simpler configuration to set up this pole in the field.

I decided to try and set it up with only the lower segment guyed. That would allow me to simply set up the pole while it is still collapsed and then push out the segments without worrying about any other guying arrangement.

Borrowing from the idea behind the clamps Spiderbeam supplies for keeping the segments extended, I bought a hose clamp and applied rubber lint that I crimped in place. I cut some of the rubber away so I could add three rings. So now I have a permanent feature on my Spiderbeam pole: fixed guy rings. 

Securing the base
You also need the bottom part to stay put. Before I would use a large peg with some soft (insulation) material around it. I would just position the pole over this peg. However I have found this is not a very solid construction - e.g. it does not allow you to keep the pole standing while it is still collapsed. With the set up I just came up with, I need the collapsed pole to stay upright while I attach the lower guy lines. So I replaced the peg with this:

The center hole fits around the pole while the other holes can hold pegs that secure this little box in its place. Trying it in the field it turned out to work well - the Spiderbeam pole kept upright while I attached the lower guys.

With these two changes I can set up the pole in no time without needing any supporting structure, like so:

I used this a couple of hours with the pole extended 18m holding an efhw wire. Granted, it was not very windy that day. I will have to see if this is strong enough in higher winds.

Practical segment clamps
One last adjustment I made to the configuration is a replacement of the clamps that hold the segments in place when extended. The default clamps provided by Spiderbeam require a spanner or wrench to open and close. That is inconvenient and so I really did not use them often. I either extended the segments to the point that they stuck (with the risk that the antenna would collapse during a QSO) or I would use duct tape (that is quick to apply but not so easy to take off). 

So I bought clamps that have butterfly tightening tabs. I added rubber strip on the inside that I crimped on the clamps to protect the pole (like with the original clamps). I tried them and they work well.

Wednesday, April 26, 2017

Finding PE4BAS

Fellow blogger and radio addict Bas, PE4BAS is on holiday. To keep his followers busy he created a little puzzle to solve: where am I?

I am always in for solving puzzles.. so here goes.

As he is a WSPR user (I think our first conversation was about visualising WSPR contacts), he can of course be found in the database. 

He is being spotted as we speak:
2017-04-26 12:26 OZ/PE4BAS 7.040044 -2 0 JO56jl 5 OH2EAT KP20xw 1003 54

So, Bas is in OZ and in JO56jl to be more precisely.  That square is not that big and there is not a lot going on there. So I sneaked around and took a picture of his place while he was not looking:


Looks familiar?

I had a look around (I hope Bas doesn't mind) and it indeed is a cosy place.

Cosy place Bas has chosen as temporay QTH
I left him alone again to enjoy the rest of his holidays. Thanks for the puzzle Bas & have fun!

Monday, April 17, 2017

Spending a lot of time at PAFF-0097

Just got home from a nice activity at PAFF-0097 as PC44FF. I brought my hexbeam but the parking I had in mind when planning the activity was too crowded. Driving around I was lucky to find a nice open space to set it up. There were some rain and hail clouds around and I was just in time setting up the beam to stay dry.

/P DX antennaThe skies cleared later on
I started out on 20m with the hexbeam pointing to NA. The band was not in a very good shape so the going was slow but I did copy a lot of NA stations (relatively). I tried a sked with VK4FW but the band was just not good enough. After 2 hours mostly on 20m - I tried 17m but that was no fun - I had logged 106 QSOs. 36 of those were with NA stations from 14 US states and 3 VE provinces. Quite a lot of familiar NA chasers in the meantime.

Personally I am OK with an activity once I reach 100 QSOs. However, as 20m was rather slow and I had not copied a lot of the familiar EU chasers, I decided to stay a little longer to try 40m. I took down the hexbeam and set up a 40m vertical (EFHW) on my 18m Spiderbeam pole. In about 45 minutes I was good to go again.

18m Spiderbeam pole with an EFHW for 40m

40m was very noisy where I was. It was due to splatter (a combination of a good rx antenna and poor filters in my FT857d) but also QRN. I changed frequencies a few times but then decided I would have to just bear the noise. It was really busy though. As signals were rather strong I could copy a lot of stations above all the noise. As chasers kept on calling there was no way for me to leave. It was getting dark and far past my negotiated return time but you can't just ignore a pile-up of chasers (well, I can't).

After 2 hours the pile up thinned and the signals dropped below the QRM level. By then I had logged 238 QSOs on 40m - apart from 4Z and SU all of them EU chasers. This makes for a total of 344 QSOs for this activity with 6 park to park contacts. A lot more than I had anticipated. 

Driving home in the dark I saw a lot of huge bonfires and remembered that in this part of the country it is tradition to make large Easter fires. It made it a magical drive home with my ears still buzzing from all the noise.

Magical views driving home

Sunday, April 9, 2017

YNOMY LX-pedition planned for May

In preparation of our expedition to BS7 or P5 sometime in the future, YNOMY DX group has planned its first group expedition. So far we have all been active from various places outside of PA individually. As a contest team we have shown to be able to work together for a couple of years already with rather acceptable results.

So now we are off to our first team expedition on May 20 and 21. We chose LX as a convenient location and we chose WWFF as the focus of our operation. Working together with the LXFF coordinator, Mill LX1CC, we have made some draft plans and acquired a special callsign to be used for this expedition: LX44FF.

Our goal is to work as many chasers as we can from Saturday morning till Sunday evening using multiple stations both on phone and CW on whatever band is open between 80m - 2m. We will also issue an award to the most active chasers - check out: LX44FF Award

Really looking forward to a whole weekend of LXFF. Let's hope conditions are acceptable or better.