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Portable 2m/70cm OSCAR antenna

After the Indian HAMSAT has been launched many hams around the globe asked me for information to get active on the HAMSAT.

One of the main questions is for an easy to use antenna. Some 4 years ago I have made a portable antenna for my trip through Europe. On my webpage you will find information about this thip I have done together with my radio friend Dirk ON1DLL (now ON5GS).

We made satellite qso’s from all the countries we visited, and the antenna we use I will describe below.

The complete antenna can be seen below:



For the antenna sizes I have used the excellent program of DL6WU. It is a simple BASIC program running under DOS, but it gives very good help with constructing an antenna.


The 2m section by DL6WU antenna program:

The best is to use only the Progressive Spacing list.

This list uses the beginning of the boom as reference, this avoids the addition of small errors when measuring from element to element. The last element will then have the addition of all errors (e.g 4x 2mm error = 8mm error for the final element !!!)


The 2m section in hardware looks like this:

For the driver elements the DL6WU program says “folded dipole”. Because a folded dipole in not easy to divide in two parts I have used the simpler open dipole with a gamma match.

In practice it doesn’t really matter if the driver is an open or folded dipole. As far as it radiates well its okay J

The 2m gamma match:

The gamma match is done with 2,5mm thick (thinned) copper wire, screwed in the aluminium element.

The gamma match is made with a small Thompson trimmer, inside the square aluminium pipe.

This is to protect the fragile trimmer and keep it from de-tuning because of outer forces (transportation, people who by accident walk over it etc…)


The elements:  

The element are made from 6mm aluminium rods, that can be screwed in the boom.

The walls of the boom is only 2mm thin and to have more “flesh” to make the screw-thread I locally placed 3mm plates at the inside of the boom. The plates are holded by two small screws like shown below.

At the places where the elements will come the boom is 5mm thick (2mm boom + 3mm small plate) and enough to make the screw-thread.


The 70cm section with the DL6WU antenna program:

The 70cm section in hardware:

The elements are mounted with the same screw principle as the 2m elements.


The spacing between the 2m and 70cm section can be seen below:

The whole antenna can be disassembled to parts less than 50cm length.

The boom is 1 meter long, and cut in half to keep the maximum length around 50cm.

This can be seen below:

The right-side part of the boom has two ‘L’ –shaped aluminium profiles mount on the boom.

They are slightly bend inside to fit tightly. The both parts can easily be push together and be separated in a fraction of a second. J






73 de PE1RAH, William Leijenaar…


This page is designed and created by PE1RAH. (William Leijenaar).