Saturday, September 28, 2019

Wet but still great activity from Ameland

In the afternoon of Friday Sept 27 I arrived on Ameland Island (part of EU-038) for a weekend with my in-laws, celebrating their 50y honeymoon anniversary. Knowing I would be on an island that also contains PAFF-0073 - the last unactivated PAFF - I was keen to take my radio with me.

We would travel to the island without a car so I prepared my bicycle so it could transport a lot of stuff.

Mountain bike customized into trekking bike with a lot of extra weight

Getting nearer to the weekend two forecasts were worrying - a geomagnetic storm with Kp up to 6 and rain with strong winds were both on the agenda for the weekend.

I chose to take a smaller pole (12m) than I usually deploy and decided I would take my mobile amp and a stack of LiPo's as they would give me just a bit more chance if conditions would be poor even though it meant my bags would be heavy.  


Strong wind on the island

When I was on the island checking the rain radar I knew I would not stay dry however I would plan my activity. So I took my rain clothes and a lot of plastic to cover my gear and went out.

Ominous clouds over the dunes at Ameland

I found a nice place in the dunes overlooking the sea. It started out nicely with some sun. There was an almost immediate pile-up on 20m that seemed to continue forever. 


12m Spiderbeam pole in the dunes fighting the wind

Conditions seemed good enough with some particular strong skips - with the benefit of sea water nearby surely. Quite a few NA stations came by some with signals up to s9 like Tom KG8P from MI and Norman N9MM from TX (a rare KFF p2p for me).




Unfortunately the rain came as expected and two times I had to "sit it out" for half an hour by just covering all the gear and myself (quite a challenge for an impatient guy like me to just sit there for 30 minutes waiting). 

I was out in the dunes for some 3 hours with 2 hours of effective radio time on 20m and 40m. By the time the third rain shower appeared I'd had enough and went back to the cottage to get dry and warm.


Later that evening - I was at the yellow circle
In the 2 hours it was busy enough. Being just before or at the start of a solar storm seems to be a lucky timing after all. I logged 238 QSOs (34 DX) from 38 DXCC, including 13 W states and 3 VE provinces. Odx was 9700km to PY1.


Monday, September 23, 2019

To activate or not to activate

Next weekend I will be on the island of Ameland (EU-038). As a radio amateur there is one central concept that concerns the mind with such a prospect: sea water!




As an IOTA reference Ameland and the neighboring islands have been activated a zillion times but there is a nature reserve on the island that has not been activated before. Another good reason to be radio-active there.

So, no discussion then: pack the radio gear and have radio fun!

Not so fast.. 

  1. I will be on the island invited by my in-laws to celebrate their 50th honeymoon anniversary - they will have put together a 24h program for the weekend with a full-time role for me.
  2. I will be on the island without my car but need to move around with my gear to be able to activate the nature reserve.

Okay, so I could probably squeeze in a few hours at the start of this social event. Any disappointment about that can be smoothed out during the rest of the weekend.
Regarding transport: I can take a bicycle with me on the island. So I am currently refurbishing my mountain bike so that it can carry all my radio gear (with bike rack and proper transport bags).

That is that sorted then?

Well, recently two other obstacles raised their ugly heads:
  1. NOAA expects we will have a geomagnetic storm this weekend with Kp values up to 6.
  2. The weather forecast shows rain throughout the weekend.
At Kp=6 there is not much radio fun to expect and being at the sea side in the dunes with wind and rain is not an option either. 

So I will be closely monitoring both forecasts to see how they will play out. I need 2-3 hours of dry spells before the geomagnetic storm starts raging. Fingers crossed.

Thursday, September 19, 2019

Stylish inverted V multiband antenna

Spending most of my radio time /P, I have over the years built and used many different antennas. The inverted V dipole was always one of them but mainly for 40 and 80m as I used end fed verticals for the higher bands (due to the length you quickly end up with an inverted V configuration on lower bands).

I started out with four individual dipoles - one for each band 160, 80, 60 and 40. During my activities I mainly use 80 and 40 of the four so I decided to combine them into one dipole for 40m and 80m - using bullet connectors to change bands. The benefit being that you don't have to change antennas - only lower the mast somewhat to reach the connectors.


Bullet connectors to switch bands

Lately I have been using the inverted V for 20m as well - adding that to the multiband version - as I have found it works well within EU and for DX and again it saves me changing antennas. 

Looking at the radiation diagrams on 20m you can see that the inverted V (blue) radiates better on the higher angles compared to a half wave vertical (red). Note that this is a broad side view. From the ends the inverted V loses significantly more versus the vertical (10dB at a 15 degrees take-off angle on 20m) - so for DX the orientation counts.


EFHW vs Inverted V - 14Mhz - 18m pole

Planning for a future trip where I would have to travel relatively light, I decided to tweak the dipole even further adding all HF bands from 6m down to 80m (160m I would hardly use and would make the antenna rather bulky). 
It took two field tests to get it right. I started cannibalizing the existing 20-80m version. After a few hours out in the field I had cut all elements and established that I needed to change the existing 30m and 40m elements. Then time ran out.
In the second run I found a few peculiar mistakes with 15m being quite a bit off (measuring error the first time?). So a few more cuts and tweaks were needed but 2 hours later my antenna was ready.

One thing to keep in mind is that the impedance of an inverted V changes when the angle between the two legs changes - which it always will between deployments. If you increase the angle, the frequency at which the impendance dips goes down. There is a "sweet spot" of element length vs angle that gives you a dip around 50 Ohm. 

One eye catching feature of my antenna is the way I have attached the elements (for when they are not connected). I started out with simple rope to hold the pieces together but as I unroll the antenna in a different way (rolling it off a cylinder) than I roll it up (adding turns by hand), the elements are twisted each time. The copper wire can cope with that but the connecting rope transforms into a small knot after a while.
So I had the idea to enable the various pieces of wire to twist independently and - having two daughters in the house - came up with a design featuring pink and purple beads. 




I am quite sure this makes it a unique dipole as far as dipole go.

I tested it out during a 3 hour activity from nature reserve PAFF-0067 on 17, 20 and 40m. I worked more than 200 chasers with great reports so it seems to work well.



Monday, August 5, 2019

FFFs during my summer holiday

During my summer holiday in France I was radio-active from various FFF locations - six in total. I usually visit four parks in two /P days out but conveniently this year both campsites we stayed on were inside nature reserves.

I have not made that many QSOs from the campsites as (1) it was by times too hot to do anything, (2) I was in a tent where my favorite mode phone gets annoying for the surrounding quickly and (3) my family expects me to socialise with them in stead of other hams.
We stayed a bit longer in the Dordogne region so I was on the air from that campsite a few times.

In total I logged 805 QSOs from 43 DXCC on 20 and 40 meter:
  • FFF-0031 Park National La Brenne (campsite) - 85 QSO FT8/CW/SSB
  • FFF-1167 Natura 2000 La Brenne - 144 QSO SSB
  • FFF-0057 Vallee de l'Anglin - 126 QSO SSB
  • FFF-2352 Basin de la Dordogne (campsite) - 194 QSO FT8/CW/SSB
  • FFF-2568 Vallée de la Vézère - 121 QSO CW/SSB
  • FFF-2570 Vallées des Beunes - 135 QSO CW/SSB
Eight OMs made it to all the locations: EA3EVL, EA7YT, OM1AX, ON4ON, PD7YY, S58AL, SP8LEP, YL2TQ.

DX was hard to find. Dov 4Z4DX made it a couple of times but from the other end only KD1CT made it across once and only barely so. I tried to get Chuck KO4SB in the log but there was no way - not even a CW whisper heard on both ends. Summer season in a solar minimum is not my favorite time as ham (as holiday maker though..). Luckily there was some sporadic E to create a bit of local fun with signals popping up and strong skips to specific areas.

Convenient picknick table in FFF-0057
In the shadow at a lake in FFF-1167 
Bit of walking required to get into the woods at FFF-2568
FFF-2570 was easy to activate once I found this parking area 

Thursday, July 18, 2019

Chilling in France

May and June have been rather busy. Apart from the normal daily routines there was an expedition weekend to GJ with my team in May and a special castle event I organised for the whole of June. Both brought a lot of radio fun and of course a lot of organizing and administration (logs, awards, QSLs, PR).

For a few days now I have been chilling on a campsite in France. The first stop is in the center of France and as it turns out (I did not plan this) the camping is inside the frequently activated nature reserve NP La Brenne (FFF-0031). I have put up a wire for 20m and did some data and CW yesterday. Conditions were not good judging from the activity level on CW. There was more activity on FT8 but that mode cannot capture my attention for too long.


Tomorrow I will go out portable to activate two nature reserves in the vicinity that have seen little activity: Natura 2000 area of Brenne (FFF-1167) and Vallée de l'Anglin et affluents (FFF-0057).

This weekend we will be moving further south to the Dordogne for 2 more weeks of camping. I will again be inside a nature reserve (again a nice surprise) and this time it is a new one: Bassin de Dordogne (FFF-2352).

I expect I will go out /P from there at least once, depending on how the weather develops. The first days look like it will be above 40C. This means sitting very still in the shadow and / or laying in the swimming pool the whole day.


Monday, June 10, 2019

QRO portable

Most of my QSOs I have made while out portable. At home I only have a simple antenna: a wire running from the attic window into the garden. Quite early on I found that to work interesting DX stations I had to have a better setup. At around the same time I discovered the WWFF and COTA/WCA programs. A portable journey had begun.

Why bother about the setup?
My radio time is rather limited. This is one of the reasons I want to make the most out of the trips I undertake. The other reason is that I like to give chasers all over the world a chance to collect references in the (worldwide) award programs I participate in as activator. 

Antennas
Trying many antennas and setups I moved from simple wire antennas via a home made cobweb to the folding hexbeam. That one still is my favourite DX antenna. I use that one if I have the time and know there is enough room to set it up. For low bands I use verticals, a c-pole (40m), delta loop (40m) and dipoles (center and end fed). 
For ease of deployment I have lately started using a linked dipole in inverted V configuration for 20-80m. I am quite pleased with the performance and the ease of changing bands.

Masts
With antennas you are faced with the next challenge: height. I started out with an extended Spieth mast (14m but very thin top) and Spiderbeam 12m mast. Fine for end fed's (vertical / sloping) or high band dipoles but once you get to 40m and below you want more height. So I moved to 18m and later even 26m Spiderbeam masts. The 18m version is the one I take out by default. I added some features to make it easy to deploy on your own in the field.

Power - applied and transmitted 
Last but not least there is the question of power. I moved to LiPo and LiFePO4 batteries for my radio's years ago. The capacity / weight ratio is unbeatable. With LiPo's you can run 100w for hours with little added weight.
Moving towards the solar minimum I was looking for a bit more TX power. I started with a cheap RM Italy amp and then moved to the Ameritron ALS500m. It provides a max output of 400w - which is exactly what you are allowed in PA.
I purchased a lead acid battery of 145Ah to power that amp - with the idea that this would allow full day operations (like when I am on expedition with my team YNOMY). However this has two downsides: the battery is *very* heavy and it only supplies 12v or even less under load. At that voltage the amp - designed for 14Vdc - is putting out probably something like 250w.
For a while I looked into voltage booster solutions but I did not manage to build something that was practical and reliable at the same time.

By the end of 2018 LiPo's had become far less expensive than when I started buying them and I had collected a few already (sunk costs). So I decided to see if I could power the amp with LiPo's. The big advantages being that the amp would run at the designed 14v with far less battery weight.

In preparation of the YNOMY GJFF expedition I built three extra batteries from individual LiPo cells I bought in China. During the expedition we have run the amp for two days on LiPo's and the radios on LiFePO4's, using the 145Ah lead acid battery as recharging unit. This worked brilliantly.


HobbyKing 16Ah LiPo, DIY 20Ah LiPo and DIY 20Ah LiFePO4

The capacity required to run the amp for a given period of time depends on a number of variables, like the mode used and how much you transmit during that time. A couple of portable activities have learnt me that I need one LiPo battery (16/20Ah) per 90 minutes of SSB activity. 
In GJ we had four 16/20Ah LiPo's and when we drained one, we recharged it from the Lead acid battery (using a balanced charger). In the end we never drained all batteries as we had a recharged battery ready when we drained the next.

Note that with the Ameritron amp you can choose two approaches. The standard power leads consist of 4 wires (2+ and 2-). This means you can attach two LiPo's and run them in parallel. This is a way to extend your operation without needing to switch batteries in between. I chose a different approach. I left the original (longer) leads and added a short extra power lead (fused). The wires are just long enough to rest the battery on top of the amp [Pic to be added].

Beware of low voltage
It is important to keep an eye on the voltage level of your batteries if you intend to use them more than once. You can buy battery alarms that monitor each cell in the battery. They will give off an alarm you cannot miss (think of fire alarms in your house) once a cell reaches a set minimum. I recommend you always have an alarm attached while using a LiPo / LiFePO4 battery.
For LiPo's in general 3.2v is used as a safe lower limit per cell. I think it is conservative and in this particular case too conservative as the current drain is high. This means that the cells will show a voltage dip from which they will bounce back a bit once you disconnect the battery. I therefore use 3v as the cell minimum for the LiPo's.
The LiFePO4 cells can go a lot lower. I set the alarm for 2.5v per cell - still quite conservative.

This setup is effective. Apart from direct experience (hardly scientific) I do once in a while get a chance to compare my results with other stations out in the field on the same day. As PAFF and COTA-PA coordinator I receive a lot of /P activity reports and logs. 99% of the time I was not out myself but the times I was, there was bound to be someone else out as well. In those cases the difference shows both in QSO rates as well as in distance covered.
This setup is also bulky. Last time I had to walk quite a distance in the sun with the radio, the 18m mast, the amp, batteries, antennas, chair, food and drink, and it was killing. Transport-wise there are still a few improvements I can and plan to make.

Lots of heavy stuff!

Friday, February 15, 2019

C-pole antenna for 40m - a dx profile at low heights

Yesterday I went out to test my newly built c-pole antenna. I have used one in the past but found out it had some construction errors - the effect of which was somehow hidden by the balun I added ( a couple of coax turns on an FT240 core). The balun did get extremely hot even with 100w - a sign something was wrong - and once I replaced it, the SWR went through the roof. 

I used an online calculator (http://svrc.org/cpole/) that turns out to give the wrong dimensions - at least for 40m. I did not notice it before but when using it again for my new version I found that adding all the various dimensions resulted in significantly less wire than the calculator specified as "total wire needed for antenna". So considerable tweaking in the field was necessary to get the antenna resonant (think of adding more than 1 meter of wire to one end).


New c-pole antenna in action

Construction
This time I used two short cheap and light fiberglass fishing poles for the horizontal spreaders. I cut them to the right length and ran the antenna wire through them. I used the caps on both ends to position the wire - making a hole in each cap and a knot in the antenna wire at each cap. Apart from their low weight and high stiffness an extra advantage over the PVC pipe I used before is the fact that the fishing pole can be (partly) retracted - decreasing the size of the collapsed antenna.

To complete the antenna I constructed a W2DU style balun. It is light and simple and still provides more than 20dB common mode suppression at 7Mhz (if you use the right beads). 

The first time I brought it out I used all my time to get the dimensions right. In the end I got the antenna to dip around 7.1 Mhz with an impedance of something like 49 Ohm - perfect.

The next opportunity to go out was yesterday. I tried the antenna from a nature reserve, to see if I could get a decent amount of contacts on 40m. It was too early to get any serious DX but I did log 150 contacts up to 2500km. So it did seem to tx and rx.

Comparing C-pole to EFHW, Inverted V and Delta Loop
The c-pole is an addition to a range of antennas I have for /P operation on 40m. I mostly use either an (almost) vertical end fed half wave or an inverted V - depending on how much space I have to set up the antenna and what kind of radiation pattern I am looking for (more NVIS or more dx). The final option I have is a delta loop (more or less corner fed - so vertically polarised). The loop is more complex to set up than the others though.

All these antennas can be used when I have my 18m Spiderbeam pole with me. They are all omni-directional but have a different radiation pattern in the vertical plane - with the vertical, c-pole and delta loop in one category and the inverted V dipole in another. 
Using my 18m Spiderbeam pole the antenna patterns (over local ground conditions) look like this:


  • Pink is the inverted V. It has nice NVIS qualities with a lot of gain on high angles of radiation (5.4 dBi straight up) but at a takeoff angle of 15 degrees only -5dBi.
  • Blue is the delta loop. It is almost the opposite of the inverted V dipole. It has most gain at a takeoff angle of 20 degrees (3.3 dBi, 3.1 at 15 degrees)
  • Green is the (almost) vertical end fed half wave. A bit less pronounced than the delta loop. It has a max gain of 1.6 dBI at 15 degrees.
  • Red is the new C-pole. It has a max gain of 2.1 dBi at 15 degrees. 

Looking at the three antennas with a "dx profile", the delta loop is the clear winner. It has more gain on low angles but also significantly more gain than the other two at higher angles. It is a bit more work to set up though and needs space.

The reason I started looking at my c-pole again is that there are situations in which my 18m pole is not available (I could not take it, or - in a team expedition - it is in use with another antenna). The next option I have then is my 12m Spiderbeam pole.
Now things are a bit different. For one, the delta loop is not an option anymore. The half wave vertical is also out of the question. That one becomes a sloping end fed half wave with quite a different behaviour.

Using my 12m Spiderbeam pole the antenna patterns (over local ground conditions) look like this:


  • Blue is the inverted V. It is still radiating most of its energy up at high angles but the max gain is now down to 1.8 dBi. Gain at 15 degrees is down to -9dB.
  • Green is the end fed half wave sloping. It is now also radiating more at high angles with a max gain of 3.8 dBi straight up. Gain at 15 degrees is -1.4dBi
  • Red is the c-pole. Max gain is now 1.7 dBi at 20 degrees and 1.4 dBi at 15 degrees. 

The C-pole does not seem to suffer that much from the change in height. It actually performs a bit better on the higher angles without losing much on the lower angles. 

Comparing the C-pole at 2 meters off the ground and 7 meters off the ground shows that this antenna is better off on my 12m Spiderbeam pole:



Red is the C-Pole with the top at about 11.5m and Blue is the same antenna with the top at about 16.5m. At low angles almost no difference but at 45 degrees the lower C-pole has 7 dB more gain (at 60 degrees the difference adds up to 13 dB).

Looking at the radiation shape of the higher C-pole (in blue) you can see a central lobe that you can expect to grow when you put the antenna even higher - and it will. However height is not a variable I can influence that much. It will be somewhere between these two extremes.

Conclusion
The practical test showed that the antenna works - I logged a lot of contacts with good reports and the SWR is now perfect - and the model shows it is a decent addition to my set of antennas, especially when I am constrained in height.