The humble dipole is really a great antenna

Because my hexbeam is still down and awaiting repair, I have been using wire dipoles and my Antron 99 to make QSOs. But I had no resonant antenna on 20 metres and was badly missing the action on that "bread and butter" band.

The apex of my inverted vees. The short one is the new 20m dipole, with homebrew insulators made from PVC chopping board!

So I recently added a 20m dipole to my nest of inverted vees. Previously, I had three vees, one for 80m, one for 40m and one for 30m. When I added the 20m dipole, I was surprised and perhaps a little annoyed to find that it was not resonant. Its inclusion in the nest did not seem to upset the VSWR on the other bands too much, thankfully, but with an SWR of 7:1 on 14Mhz, it simply was not effective and not radiating efficiently at all.

Astonishingly, I did not have an antenna analyzer. It's a piece of equipment that every shack should have but it's something I had never invested in. During a conversation with some fellow DXers on a WhatsApp group, I got chatting with John EI3ISB, who kindly offered not only to give me a MINI60S analyzer which was surplus to his requirements, but also to come to my home and help me analyze the 20m dipole and either extend it or trim it to resonance.

A wider view of the inverted vee dipoles. 

Yesterday morning, Saturday, John arrived and within a short time we found that my 20m inverted vee dipole was resonant on 15.67Mhz – way above where it needed to be. I still do not know how this happened, except that I must have been using the wrong online dipole calculator or else I made a mistake in trimming the two legs. Either way, the antenna needed to be LENGTHENED. And not just by a few centimetres, but actually by about 50cm.

I lowered the dipoles down using the pulley rope and we quickly got to work on adding a piece to each leg before hoisting the whole lot back into the air again.

A quick check with the analyzer revealed that resonance was achieved towards the top of the 20 metre band, at around 14.300Mhz. I lowered the pulley rope again and added another 5cm or so (a couple of inches) on each leg and raised the dipoles again.

This time, resonance was around 14.100Mhz, which is pretty good. I do a lot of digital modes, and prefer CW to SSB, so this was a more than acceptable point of resonance.

John left and I was grateful for all his help. I was finally operating properly on 20 metres! I had a very rewarding day on the band, working DX on FT8 in most parts of the world.

A screenshot from PSKreporter.info showing where my 20m signal has been heard during the past 24 hours.

I hope you can see from the above screenshot that the dipole has been very effective in carrying my signal to various parts of the world. I see that I was heard in the Falkland Islands, in Alaska and in Kenya. In fact, I worked 5Z4VJ in Kenya using FT4 yesterday evening. Other DX stations worked included several JA ops, YB0MWM in Indonesia, BG0BBB and BD7BS in China, ZP9MCE in Paraguay, A45XR in Oman, LU8EKC in Argentina, 9Y4DG in Trinidad and Tobago, YV5JLO in Venezuela, along with several stations in the United States and Canada.

Reverse Beacon Network reports for my 80m inverted v

Last night I decided to see how my signal was getting out on my new 80m dog-legged inverted v antenna. I put out a CQ on 3.150 Mhz and waited to see what the reports were like on the Reverse Beacon Network (RBN), which is a network of automated skimmer stations automatically spotting what they hear on the bands on the CW mode. 

I was quite impressed with the results. I was being heard in different parts of Europe, including Germany, Norway, Sweden, Hungary and Slovenia. Indeed I have worked a couple of stations in the USA using just 100 watts. The inverted v is definitely hearing better than my Butternut HF6V, but I am in a housing estate and the band is still quite noisy. I have made a few contacts on 160m (top band), although due to the low apex height of about 9 metres or so (30ft), I suspect that I won't be making many contacts on top band, where the nested v system (80m/40m/30m) has a 3:1 SWR at the bottom end of 160m. However, I will hope to enjoy a nice bit of activity on 80m CW during the winter months. I still have the Butternut in place, and it is currently tuned to the top end of 80m, so I can try to enjoy the best of both worlds!!

The challenges of 80 metre operation from a small garden

Regular readers of this blog will already know that I operate from a small garden. You will all know that this hasn't prevented or deterred me from working DXCC on every band from 80 metres through 10 metres. My lowly Butternut HF6V, which is 26 feet tall, and ground mounted in a corner of the garden near the wall, has enabled me to operate in a limited capacity on 80m. Through last winter, especially as a result of my participation in the CQWW CW contest in late November, I was able to finally get 100 countries confirmed on that band on LoTW.

But I have never been able to enjoy good operation on 80m because the Butternut is too short and therefore limited in what it can hear. It gets out reasonably well for the DX stations, and the low angle of radiation definitely helps.

A photograph of my nested inverted vees, with labels.

Just this week, I decided to put back up the 80m inverted V, off the same feedpoint as the Vees on 30m and 40m. From previous experience, I knew this would involve some serious dog-legging. (For non amateurs, this means making the wire antenna "turn a corner", so to speak, because there isn't enough room for a straight run of wire that's 66 feet long on each leg. One leg - the "reflector" - is able to get a run down along the side of the house, as far as the gate pillar at the front, although about three feet of it still needs to be dog legged.

The other leg - the "transmit" leg - runs down above the back wall of the garden, and then dog-legs up the side wall of the garden to a point at the back wall of the house under the eave. From there, it is dog-legged again by about three feet and tied off. And the mast (insert word "pole" here!) is only 30 feet at the apex.

It's far from ideal, I know. I bet some of you are trying to picture this all in your head and wondering how I've managed to defy the laws of physics, and indeed the laws of effective radiation of RF fields. So how's it working?

The reflector leg of the 80m inverted v dipole runs down
between the houses and is tied off (dog-legged) at a gate pillar.

Here's a summary of the contacts made last night on CW using just 100 watts: PI4EME, US8UX, EI3HMB, HA5OV, IK6DIN, YU9CF, EI6IL, F5TVG/P, HB9FBA, EI7BA, S51FZ, GM3ZLC, EI2EO, UT8MM, G4LEM, PA1MUC and HB30OK. So it's getting out, as far as Ukraine. Hardly a comprehensive test of its abilities, but the reports coming back were generally 579 or 599 or 599 plus! The previous morning, I had worked N8NA on 100w on CW, so that wasn't bad either, but it's likely that he's got bigger antennas than me.

Time will tell if it's up to the job of making more distant contacts. I will run 400 watts when conditions improve and the band quietens a bit - the QRN here can be s9 at times.

Interestingly, the 80/40/30m nested V system also has some resonance on the lower portion of the 160m band. When I say "some", I mean about 3:1 at best, maybe 3.5:1. It might allow me a limited amount of operation on that band over the next couple of months. I may figure out a way to tune it better for 160m. We will see.

In the meantime, I will keep you posted as to the performance of this compromise antenna system.

6 metre beam installed - just in time for the first opening!

On Saturday I finally upgraded my 6 metre (50 Mhz) antenna. I have been using a simple aluminium dipole since the sunmer of 2010. It has served me well, giving me 54 DXCCs over two seasons. But I have been hungry for something with a little more gain so that I might notch up some new DXCCs this year. So when I chanced upon a three-element beam for 50 Mhz I snapped it up! Tony EI4DIB and Jim EI2HJB, who have been involved in so many antenna installations at my QTH, made themselves available on Saturday afternoon and we set to work. It was cold and windy but sunny. So typical Irish weather !

Tony EI4DIB and Jim EI2HJB installing the 3-element 6 metre beam

This was not a complicated installation in that we were swapping out a 6m dipole with a beam, so we could use the same coax. We were also swapping my 4m folded dipole for a 4m dipole made from my recycled 6m dipole shortened down. Tony and Jim managed to get the SWR of the beam between 1.5-2 so that was fine. It is under the 2m XY beam on the same rotator. I am now well set up for VHF activities!

This afternoon, Sunday, the 6 metre band opened for the first real Sporadic E opening of the year. Very timely too! I put the beam through its paces. I worked a number of stations in Poland and Lithuania and Latvia. Some of the signals were very strong indeed. I was delighted. Below is a video of me working SP3OCC, Ted in Poland, on SSB. I had just worked him on CW. He was 10dB over 9 at times. Very strong.

Below are maps from DX Sherlock showing just how active the band was today. It really opened up for a while in Europe, although the openings to EI were limited along a narrow path to Poland and the Baltic area.

6 metres open in Europe, with my first QSO mapped

Activity was intense for a time on 50 Mhz

This was an unexpected opening, especially such a big one. My first QSO of the E season in 2011 was on May 1st, so we are just a few days short of that date and the band has opened properly for the first time. While 50 Mhz was active last summer there wasn't so much DX to be worked so we are hoping that this year there will be some new countries floating around. And with the three-element beam now instead of the dipole, here's one op who's chomping at the bit for some extra DXCCs! Happy DXing . . .