Or how to spend a lot of time building antennas!
A week ago, two of us dedicated hams decided to prepare for the VHF contest (2 and 6 meter). I only had a magnetic mount car antenna for 2 meters. David K1KK decided to fix this in a BIG WAY. By the end of two weeks, we had three high performance antennas on each of these two bands, raised a tower with a rotor and had two radio stations running, IC-9700 on 2 meters and IC-7300 on 6 meters. Yep, Jed, I’m tired now! Here is how it went down…
2 Meter Band:
We started with a “Slim Jim” antenna (see the specifics here) that was made out of 450 ohm ladder line hauled up a mast. Due to the height on the pole, it managed to get all the repeaters in a 75 mile radius. Great performance for such a small antenna. Great for emergency use to be slung in a tree when needed.
The next antenna was the 4 element collinear center fed (with ladder line) wire antenna also placed on the 50′ mast. That had serious gain in all directions and managed to get all the repeaters and made FT8 contacts all the way into PA. David built a balanced antenna tuner for VHF to take coax and be able to feed 450 ohm line to the mid point of the antenna. This had a high “Q” so it was more “peaky” or needed tuning when moving to the other end of the band.
The third antenna was the three element collinear wire antenna taped to a 40′ fiberglass mast (fed at the bottom with coax to a matching 1/4 wavelength stub). This did not have the same gain as the four element one but was somewhat more broad banded.
Oh, yeah, I forgot about the LFA Yagi antenna for 2 meters (Loop Fed Array) or beam antenna put at the top of a short tower. This is able to focus the RF energy in a specific direction, the direction controlled by the rotor at the top of the tower.
6 Meter Band:
Let’s start with the 6 meter LFA beam antenna just under the 2 m LFA at the top of the tower. This was a work horse on 6 m and made most of the contacts as it had the directional ability to catch the sporadic “E” layer openings that came and went as fast as the wind. With these openings, we heard Israel, Norway, Sweden, Scotland and England and managed to complete a few QSO’s with them.
Next is the 6 meter vertical yagi described here pointing to Europe. This was fun to build out of simple tools and wire.
How about building a 6 meter two element end fed collinear as an extended double Zeppelin? Boy is that a mouthful! Worked well but the 6 m LFA beam had it beat only by a few dB and a lot less work. This is a great antenna for field day as it can be put up in a matter of minutes.
The LFA’s needed a tower to really perform and we did not have time to pour concrete and build a permanent tower. Multiple trips to Lowe’s gave us the threaded rod, “U” clamps to attach the legs, multiple augers and guying wire to support the structure. We got our exercise screwing in 5 augers or ground screws and attaching two 10′ Rohn 25 tower sections together. Attaching the rotor, mast and LFA’s to the tower was a job not for the faint of heart. Running the cables to the shack and putting up the guys to hold it finished to installation. This was very worthwhile as it produced the most results.
On 6 meters, we made 34 contacts on FT8, one on CW and one on SSB. 2 meters understandably has fewer contacts due to the propagation issues but we made 7 contacts on FT8 and none on CW or SSB. On Saturday 2 m did relatively well but heard the same stations on Sunday. Some of these stations were as far away as Pennsylvania. 6 m was good most of both days but it was amazing how few CW or SSB signals were out there. A raw score of 1,850 points. The contest ran for 27 hours but by Sunday afternoon, we were tuckered out!. We did eat like kings however, Steak and baked potatoes for supper and waffles with Eggs Benedict (eggs, spinach, Canadian bacon, Hollandaise sauce on fresh waffles) for breakfast.
We did make a call on the 147.090 repeater to invite BARC members to come by and partake in the fun but did not get any replies, maybe next time! Stay tuned for the Antenna modeling and testing class we will have in the fall.