Receiving SAQ and other VLF stations

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The huge VLF antenna of SAQ near Grimeton, Sweden (credits).

This article is about receiving radio stations operating in the VLF band (3-30 kHz). Due to the very low frequency, receiving such stations requires some special equipment, since most radios don’t support these low frequencies. One of the interesting stations in this band is SAQ, which occasionally transmits at 17.2 kHz. Other stations include submarine communications and time services. — more →

Short DL6WU yagi for 23cm

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My 23cm yagi antenna, in fixed position to the local ATV repeater.

In the previous Winter I built a HB9CV-in-a-box for 23cm for my uplink to the local ATV repeater PI6ATV. Although this antenna works nicely, its gain just isn’t enough when their 23cm preamp is broken (which, unfortunately, is the case most of the time). To achieve a more steady uplink, I decided to build an antenna with a bit more gain, at least 6 dB extra compared to the HB9CV. A short yagi should make this possible. — more →

5/8 Wave vertical antennas for HF

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Our 5/8 vertical for 20m, during a windy day.

Lots of radio amateurs build their own verticals. Most of them tend to stick to vertical antennas with a 1/4 or 1/2 wave sizing. Just a happy few build a 5/8 wave vertical antenna. This is remarkable, since the 5/8 has the lowest angle of radiation and has about 1dB more gain (compared to 1/4 and 1/2 verticals). So the 5/8 should be the favourite choice for DX’ing.

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Altoids L-tuner

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My Altoids L Tuner

A while ago Tjeerd PA3GNZ donated me some Barkleys mint tins (identical to the famous Altoids tins), which are rather popular by QRP builders to house small homebrew stuff. Two weeks later I found a czech webshop, offering a kit called “Altoids L-tuner”. This kit perfectly fits in such a tin. Since this tuner would be a perfect add-on for my 30m QRP transceiver, I immediately ordered it. — more →

70cm bicycle antenna

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My bicycle with 70cm J-pole antenna attached to the carrier.

During the summer season I sometimes travel to work by bike. It’s a 21 km trip through the countryside, passing cornfields, orchards, deer and spoonbills. The road includes dikes and bridges, and even a ferry to cross one of the branches of the river Rhine. Especially in the early morning it’s a real pleasure to enjoy all the surrounding nature.

I thought it would be nice to chat with some local radio amateurs on my way back home. I often talk to Adrian PA0RDA while driving home (by car) after work, using the local 70cm repeater PI2ZST, so I decided to prepare my bike for this UHF band. — more →

PoRG v2

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The PoRG v2, in a nice blue box, now including a built-in power supply.

A couple of years ago I built my first PoRG (abbreviation for “Power over RG-cable”), a simple phantom power supply to power some device over antenna cable (e.g. a preamp, active antenna, coax switch, etc). I recently built an active antenna for Adrian PA0RDA, and since his tests were very successful he wanted to have his own PoRG. For me this was a nice opportunity to reinvent this little thing:

  • I included a built-in power supply, so no external power supply is needed anymore.
  • The built-in power supply also prevents the PoRG from moving around your shack due to the forces of the connected cables.
  • It has different connectors for hooking up the transceiver/receiver and antenna, making it more difficult to accidentally swap the cables, insert DC power into your radio and see smoke appearing through the vents of your rig.

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A very small active antenna

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The kit contents: extensive documentation, a professional circuit board, and all necessary components.

Small active antennas like the “mini-whip” (by PA0RDT) are very popular at the moment. They provide good reception of signals from HF all the way down to the VLF band. Here in the Netherlands Van Dijken Elektronica sells a nice kit for this antenna, and since Adrian PA0RDA was interested in this antenna, I ordered this kit and built it. — more →

HB9CV-in-a-box antenna for 23cm

The antenna is mounted in my pole, just below the 23cm LNC. Both are pointing at the PI6ATV repeater.

The antenna mounted in my pole, just below the 3cm LNC. Both are pointing at the PI6ATV repeater.

The HB9CV has been a popular antenna for decades, especially on the 2m band where it is commonly used for direction finding (foxhunt). Others create arrays of HB9CV antennas for DXing. Since I needed a simple antenna for 23cm (to uplink to the local ATV repeater PI6ATV) I thought it would be nice to use this HB9CV design.

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Is our 80/160m HEDZ suitable to work Americans at 160m?

Adrian PA0RDA and his Drake TR-7

Adrian PA0RDA and his Drake TR-7

Last weekend was the yearly ARRL 160m contest. Adrian PA0RDA and I were still a bit in doubt about our HEDZ antenna for 80 and 160m: is it suitable to work American and Canadian stations at 160m? So far we never heard any station from that area on that band, so Adrian decided to bring his Drake TR-7 for the weekend and try to work these countries during the 160m contest, probably the best opportunity for this test. — more →

All antennas up again

All antennas are in place already for the 2014 PACC contest. Meanwhile they allow me to work HF bands during the Winter season.

Last year the field was in such a bad shape, that we were not able to setup the half extended double zepp for 80 and 160m. This year we had some nice weather in November, allowing us to get all antennas up in a rather short time.

We get used on erecting all those poles, since we do this at least twice a year: at the start of the winter and at the REC fielddays in June. Except the HEDZ, all antennas can be setup by one single person.

My 2013/2014 antenna setup for HF: monoband verticals for 10, 15, 20 and 40m; HEDZ dualband antenna for 80 and 160m.

My 2013/2014 antenna setup for HF: monoband verticals for 10, 15, 20 and 40m; HEDZ dualband antenna for 80 and 160m.

First antennas placed

This year Adrian PA0RDA and I hope to be back in the PACC contest. Our main goal is always to improve our own score, combined with having lots of fun on the bands and test our homebrewn antennas. This will be the antenna setup for PACC 2014:
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  • 10m: monoband J-antenna
  • 15m: monoband J-antenna
  • 20m: monoband 5/8 vertical
  • 40m: monoband 1/4 vertical
  • 80m: zepp (new!)
  • 80/160m: half extended double zepp
  • Beverages to Southeast Asia and Australia (not sure yet)

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J-pole antennas for HF bands

Introduction

I’ve been using J-pole antennas on the 2m band from the first day I got licensed. They perform very well, are easy to construct and are cheap. Since Adrian PA0RDA and I have been experimenting with vertical antennas for HF, we came to the idea to try those J-poles on HF.

This idea is not new. Many radio amateurs have tried this before, like DK7ZB. The J-pole antenna is almost identical to the Zepp-antenna, which is a still a popular HF-antenna. — more →

Wind, wind, wind

December was a very windy month. Most antennas did held, however the fibreglass pole of the 20m vertical broke. We contacted the supplier (DX-Wire, Germany) and luckely spare tubes were available for a few euro’s. So we ordered a replacement tube, and also ordered 2 more masts for future use.

We were not able to do lots of testing on the antennas, since work lasted too much time. So that has to wait for the next month.

Squalo antenna for 6m

Introduction

squalo-6m-1Adri PA0RDA, a friend of me, is trying to do some DX on 6m for a while now. His antenna position is very poor: he lives in the bottom flat of a 5-floor building. He has a balcony on the rear (south) side, but high buildings are very close, he has no direct sight in any direction. At the balcony he has a Diamond V2000 vertical antenna for 6/2/70, and an MFJ loop antenna for 15-40m. The 6m band is his most popular one, since he get best results on this band. However, since most DX on 6m is horizontally polarized, he needed a horizontal antenna. I remembered an all-direction horizontal antenna made by Jan PA3EGH (one of the members of the local radio club). So I contacted him, and he pointed me at his website. It was the “Squalo” antenna, or square halo. In fact, it’s just a square folded dipole. It radiates in all directions, with -4dB gain on the sides (compared to the front and back side).

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Finalizing the antennas

Thanks to a interesting article about the so called Half Extended Double Zepp (HEDZ) by W5DXP we managed to get our EDZ working om both 80m and 160m. The antenna is working fine now on 80m. I couldn’t test in on 160m yet, because my own rig (IC-730) doesn’t work on that band, but the measurements with the MiniVNA show a acceptable SWR between 1800 and 2000 kHz. When breaking up we will do some physical measurements to see what the exact size of the dipole and feeder is. The (H)EDZ is also a little bit lifted now, the center is 12 meters above the ground, the endpoints 8 meters.

We also erected the remaining antennas: the 1/4 wave vertical for 40m, and the HyGain AV-12AVQ for 10/15/20m. In the upcoming weeks we will extend the number of radials for the 40m vertical.

Setting up antennas on a corn field is not really easy. Ok, there’s no corn in the winter, but the field is very wet and muddy. When the temperature drops below zero, the field becomes icy, and above zero the amount of mud under your (wooden) shoes grows with every step.

Optimizing the EDZ

In 2009 we built an extended double zepp (EDZ) for 80m, which also performed really nice on 160m. Although the antenna performed well in the past contests, it was always a big trouble to match it. After lots of experiments and measurements, we finally found an unexpected relation between the length of the feeder and the “resonance” frequency. Ok, this antenna is not resonant on the desired working frequency, it only provides a workable impedance and very well radiation at some point. I always thought that this point was merely depending on the length of the dipole, and that the length of the transmission line merely influenced the impedance. Well, not for the EDZ! It is a non-resonant antenna, and all sizes do matter! So this makes the antenna a bit more complex, compared to a simple halfwave dipole.

We found some websites stating that the length of the feeder line should be about 48 degrees, so 48/360 wavelength. We want to have a 80m EDZ, center frequency at 3700kHz (= 81.08 meters), so the length of the feeder line will be 81.08 x 48 / 360 = 10.81 meters. This is not a practical length, since the shack is not right beneath the antenna. So we add 1/2 wavelength feedline, resulting in a total length of 10.81 + (81.08 / 2) = 51.35 meters.

Setting up the EDZ took quite some time. We had to options: the weekend of 4/5 December, or the weekend of 11/12 December. The first weekend would be freezing cold, the second weekend really wet. Since the cornfield is almost inaccessible when really wet, we decided to go for the first weekend. With the snow hitting in our face, ice hidden below the fresh snow, and a really cold wind, we managed to set up the EDZ. But due to the bad weather and ground surface conditions it took us lots of time, so we did not manage to get the feeder in the correct length. Two weeks later, the dipole came down due to the large amount of ice. So there is still some work to do on the EDZ…..

Restauration of my Hy-Gain AV-12AVQ

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Fieldday setup of the revised AV-12AVQ antenna

After more than 40 years of service of my Hy-Gain AV-12AVQ groundplane antenna, of which 25 years on top of an apartment building at about 100 feet, Ernest PA3HCM and I decided that it was time for some refurbishing. The plastic parts were partly broken and others suffered from the heavy conditions the antenna had experienced. — more →

HEDZ antenna for 80 and 160m

Introduction

The HEDZ for 80m and 160m requires 3 poles A, B and C. Pole B is 15m tall, A and C are 9m. The distance from A to C is over 100m.

The HEDZ for 80m and 160m requires 3 poles A, B and C. Pole B is 15m tall, A and C are 9m. The distance from A to C is over 100m.

The zeppelin antenna (or simply “zepp”) is a popular end-fed wire antenna for shortwave bands and has lots of simularities with the J-pole antenna. It consists of a long wire (half wave length), connected to one of the wires of a balanced feedline (quarter wave length). The idea is that the end of the wire has a high impedance, and the quarter wave transmission line transforms this to a low impedance, at least low enough to get to 50 ohms using a balanced tuner. A Double Zepp is a normal zepp, but the other (unconnected) wire of the feeder is also connected to a second wire. The Extended Double Zepp (EDZ, sometimes also known as Double Extended Zepp or DEZ) is the same, but the wires are now 5/8 wavelength instead of 1/2. The tricky part of this antenna is now the length of the feeder. Paul N8ITF gives you the measures for all versions of the EDZ. — more →

DK7ZB yagi for 144MHz

Introduction

The result.

My DK7ZB yagi for 144MHz

After the somewhat disapointing results of the DJ9BV antenna, I decided to try another model. This time I selected a 9 element DK7ZB for my test. I already bought some square alu bars, each 250cm tall. Since the 9 element DK7ZB is 5 meters tall, this should fit perfectly.

Click here to visit DK7ZB’s homepage, including all his antenna designs and lots of references. — more →

DJ9BV yagi for 144MHz

Introduction

I just started building a new yagi antenna for 144MHz. I used to work with short yagi’s, based on DL6WU, with 6 elements. These antenna’s were about 2m long. I stacked them, tested them both vertically and vertically polarized/stacked, etc. I did lots of DX using these antenna’s. After a long period without radio activity I finally decided to start again with the hobby and try another antenna design. — more →

6-Element yagi for 144 MHz

Introduction

My homebrewn VHF yagi antenna's in Elst, stacked, about 12m above the ground.

My homebrewn VHF yagi antenna’s in Elst, stacked, about 12m above the ground.

I designed this antenna in 1995. I wanted a horizontal antenna which has nice characteristics for contest usage. The side lobs are minimized, the beam width is quite large while it has a reasonable gain and front/rear ratio. — more →