ham radio

160m double L antenna

After much planning and modeling of various different antenna types, I finally settled on a very simple antenna for 160. The reason? This one works just about as well as the larger more complicated antennas, yet it leaves enough room in my yard that I can build better antennas for the other bands, too.

The antenna I chose? The Double-L Antenna by K2KQ, a compact vertical dipole for 160m. I built a monoband version, though others have built this antenna for multiple bands.

Vertical H antenna: radiator length vs height vs gain

The N6LF vertical H antenna is an off center fed, capacitively loaded, vertical short dipole. This antenna is a compact alternative to the quarter wave vertical, giving just a little bit less gain than a quarter wave vertical but without the extensive radial system a vertical requires to get decent gain. The gain pattern of the vertical H, shown on the right, is similar to that of a quarter wave vertical antenna, with only about 0.5dB gain difference between the peaks and the "nulls" at a 30 degree takeoff angle.

Common wisdom holds that the longer the radiating element on a capacity loaded short dipole is, the stronger the radiated signal. On the other hand, the closer the bottom capacity hat is to the ground, the higher the ground losses. This suggests that there may be some kind of sweet spot, where reduced ground losses are significant and reduced gain from a shorter radiator are no big deal yet. Lets find the sweet spot for a 160m vertical H antenna.

Nasiballen ronde

De nasiballen ronde is een nederlandstalig zendamateur net, elke dag te horen om 1600 en 2100 UTC. De net controls voor de nasiballen ronde zijn meestal AC6VN Harm en ON4ACH Marc. Het net heeft regelmatige deelnemers uit Europa en Noord Amerika, maar ook af en toe uit Australië en andere delen van de wereld.

In het algemeen is de nasiballen ronde te vinden op 14173 kHz. Als die frequentie bezet is, dan wijkt het net uit naar een andere frequentie. AC6VN Harm toont de nasiballen frequentie ook in zijn Skype status.

Alle nederlandstalige zendamateurs zijn welkom in de nasiballen ronde.

160m spiral loaded vertical dipole

This is the smallest 160m antenna to date. It is a simple spiral loaded vertical dipole, 17 meters high and with the spiral arms extending to almost 4 meters out, for a total space of just under 6x6x17 meters. I will not be building it, since it has about 1.5dB less gain than the vertical H antenna over the very poor ground in New Hampshire. However, this may be the largest 160m antenna people with small yards are able to put up, so writing an article will still be useful.

More small 160m antennas

The last series of compact 160 meter antennas were not that satisfactory. Luckily, there is an easy, relatively compact and better performance 160 meter antenna design available, created by Rudy Severns N6LF ("Another Way to Look at Vertical Antennas), described in practical notes on John Tait's Antennae for the Low Bands page.

With some creative modeling, we can explore and possibly improve this antenna design.

How to build a slingshot antenna launcher

Slingshot antenna launcherSlingshot antenna launcher Slingshot antenna launchers are used to launch a line over a tree branch, so antennas can be suspended from high up trees. They can be purchased from various sources. However, I like home brewing so I thought it would be fun to build one from scratch. In order to create a nice how-to document for hams on a budget, I built my slingshot antenna launcher with only the cheapest components - total price just under $20. The total assembly time was about half an hour. The end result is satisfactory, with the fishing weight (and line) nicely clearing even the tallest trees in my yard.

A multi-band HF loop antenna

Amateur radio has 10 HF (shortwave) bands, from 1.8 MHz (160 meters) through 28 MHz (10 meters). The different bands are great for talking to amateur radio operators (hams) at different distances, different times of the day, different seasons and different times during the solar cycle. Only one problem: most hams do not have space in their yard for 10 different antennas. Fortunately it is possible to build one antenna that can be used effectively on most of the bands, for example this 80 meter loop antenna.

Modeling compact 160 meter antennas

I am a recently licensed amateur radio operator, callsign AB1KW. Like many other ham radio enthusiasts, I have a yard big enough to fit a nice antenna for 80 meters and the higher HF bands, but not quite big enough for a full size dipole antenna for 160 meters. Furthermore, I have no desire to dig up the yard to lay dozens of radials for a vertical antenna. There is about 5 meters of woods between me and the neighbors on the sides and about 15 meters of woods between me and the neighbors in the back, so there is space for an antenna. I have used xnec2c to model 4 different antennas for the 160m band and found some interesting results.

QSL cards ... "soon"

AB1KW QSLAB1KW QSL In the few months that I have been on the air, I have made a little under 700 contacts, and received a handful of QSL cards. Because I want to send back something nice, I ordered QSL cards from UX5UO QSL print. Once I get the cards, I will send one to everybody who sent me a card, as well as a few people who requested a paper QSL card on the air. If you sent me a card, please wait a little because the UX5UO print queue is long. I have received a few UX5UO printed cards and can assure you they are worth waiting for.

PSK 31 frequencies

There are many web pages listing the psk31 frequencies from the band plans. Unfortunately, the planned psk31 frequencies vary from (ITU) region to region on some bands, or end up conflicting with other traffic. That is why am making yet another psk31 frequency list, this one containing the actually used frequencies, without any regard to the 'official' ones.


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