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.