Antennas On The Tower – Part 4 (Odds And Ends)

Finished Tower - Another View

Up the Tower

We completed all of the integration steps for our new antenna system recently and finally got everything on the air. I guess its safe to say a big project like this is never truly “all done” but we have all of the important work complete.

I spent some time weather proofing all of the cables as they enter and exit the conduits to the shack. The conduits are constructed to allow water and condensation to drain into the ground so the goal here was to keep the water entering the conduits to a minimum. I also spent some time to make the cabling at the base of the tower a little neater and to ensure that things were securely fastened. I also weather proofed several connectors at the tower and shack end of the feedlines and antennas.

Finished Tower Base

Finished Tower Base

We also installed a 1:2 UNUN on our 160m Inverted-L antenna. The antenna has an impedance of approximately 25 ohms at resonance which makes the SWR a little high and limits the antenna’s 2:1 SWR bandwidth.

160m Inverted-L With UNUN

160m Inverted-L With UNUN

We secured a 1:2 UNUN from Balun Designs to better match our 160m antenna to the 50 ohm feedline. As you can see from the picture below, the UNUN worked out quite well and the resulting 2:1 SWR bandwidth of our 160m Inverted-L is about 60 kHz at the base of the antenna.

160m Inverted-L SWR

160m Inverted-L SWR

Our final antenna farm consists of the following antennas:

The next project was to re-cable our antenna switching consoles to fully accommodate the new antennas including the 2m and 70cm Yagis as well the two feedlines to the 4 over 4 array of SteppIR DB36 Yagis. Our current antenna switching system consists of a manual array of switches that can route up to 8 antennas to any of four radios. This is done via two stages of switching. The first selects which antennas are assigned to which radios.

Antenna Switching Consoles

Stage 1 – Antenna Switching Consoles

The second stage consists of a switch at each radio which selects among the assigned antennas.

Antenna Switching At Radios

Stage 2 – Antenna Switching At Radios

This system, in conjunction with a set of ArraySolutions FilterMax III Switchable Bandpass Filters allow both Anita and I to operate simultaneously of different bands or to operate in SO2R or Multi-Multi modes. We can use our Custom Feedline Breakout System to route our two SteppIR DB36 Yagis to different feedlines so that we can each use of the two HF Yagis simultaneously.

Bandpass Filters

Bandpass Filters

Our tower gets quite a workout when Anita and I are both operating simultaneously!

The switching for 2m and 70cm is much simpler. Our shack has one radio (an Icom IC-9100) setup for these bands and we use two UHF Antenna Switches in our console to select between the our M2 Systems Yagis on these bands or a Diamond X300NA repeater antenna on a 45 ft mast.

Diamond 300-XA Antenna On Mast

Diamond X300NA Antenna On Mast

With the re-cabling of the antenna switching complete, we were able to get our new 2m and 70cm Yagis on the air and fully test the associated preamp and sequencer systems. This setup works very well with our Icom IC-9100 radio. The preamps provide about 20 dB of gain and the M2 Systems S2 Sequencers automatically switch them in and out when we key up the IC-9100. The added gain from the preamps really helps with weak signal work on the 2m and 70cm bands. You can see the sequencers in operations in the following video of a 2m SSB QSO with N1RJX.

It is going to be fun doing weak signal work on 2m and 70cm and we are planning to participate in some VHF contests in the future. I also want to try some EME work when the moon is on the horizon. Our antenna switching setup on these bands can accommodate more antennas and I am planning to add antennas for Low-Earth satellites and possibly EME work in the future.

I also integrated our Green Heron Rotator Controllers with our computers and the Ham Radio Deluxe Software which we use. This allows us to point  our beams with a mouse click. You can see the point and shoot rotator operation in action in the following video which captures a QSO between PY7DJ in Brazil and 5H3CMG in Tanzania on 20m. Note how the signals come up out of the noise as the 4 over 4 array of Yagis swings in the direction of the participating stations. You are hearing PY7DJ off the side of the array but he is still quite strong. 5H3CMG indicated in an earlier QSO with me that he was using a low dipole and 100W. The strength of his signal is an indication of the performance of our antenna system.

We also cleaned up the supports for our 80m loop. It is important to have a setup that keeps a constant tension on the support ropes when the anchoring trees move in the wind. We used the same setup that has worked well on our OCF Dipole for some time. This setup consists of a pulley attached to a tree and a rubber tarp anchor which maintains a constant tension on the support line as the anchoring tree sways in the wind.

Wire Antenna Anchor

Wire Antenna Anchor

Given that I had the ladders out to do this, I also took the opportunity to adjust the supports for our other antennas and do our annual antenna checkout and maintenance routine prior to the onset of winter.

At this point, we are looking forward to enjoying operating our new station! The work to date has been really rewarding and we have learned a tremendous amount from everyone who has helped us. I guess some would say that all of this equipment would not be something they would want to have in their back yard but to a dedicated Amateur Radio operator, a tower and a stack of Yagis is truely a thing of beauty! I sometimes catch my self looking up the tower and staring at all of the gear up there. Each item has a story and there are many good memories about the journey to get to this point.

Up The Tower At Sunset

Up The Tower At Sunset

So what comes next for our station? We are planning to add a computer controlled automated operating setup from microHAM and we will mostly likely be installing it sometime this winter. We are also planning to setup our SteppIR BigIR Vertical in a new location and add a receive antenna system for the low bands. We are also considering antennas for Satellite operations, EME, … My next project is going to be to learn Morse Code and become active on CW.

Completed Tower And Antennas

Completed Tower And Antennas

– Fred (AB1OC)

One thought on “Antennas On The Tower – Part 4 (Odds And Ends)

  1. Congratulations to you and Anita. Well done! Boy does that ever look like a fun radio installation. Hope you enjoy it now. Thanks so much for sharing your experience with us all these months. I personally enjoyed each of your updates very much.

    Best regards Ernie

    Westford , Ma 01886 Cell: 978 399 3183 Sent from my iPhone

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