Hello Operators
For some time its been a goal to add additional HF antenna capabilities to the tower. The first thought was adding a yagi! Unfortunately, using a yagi can be likened to firing artillery. Identify target, shoot, correct, fire for effect. Highly Effective! A mono band yagi is perhaps the best tool a contest or DX station operator could ask for. It is an excellent tool, but not as the only antenna, and not as a primary EMCOMM antenna.
Currently there are three yagis up on the tower. All are either VHF or UHF. My tower configuration would require giving up one or more of the VHF/UHF yagis, in order to put up a mono band yagi. Wanting effective communications for 80 meters, a large yagi would require giving up too much, even when augmented by various wire antennas.
I know there are diy hexbeams projects and on offer, but doubting their robustness or longevity tower deployed, at this latitude. Moreover, rarely if ever have I seen one configured for 80 meters. A 2 element 80 meter yagi would fit, but not in this time frame. Definitely something to look at in the future. Since I don’t know where the signals will be coming from, an omnidirectional antenna seems to be the best approach as my primary 80m antenna. Not as effective as a yagi, but with a fair sized plot of land, a full wavelength horizontal loop antenna on 80 meters could be rather effective, for my operating requirements. With that said, I have decided on a SKYLOOP antenna. One which is a full wavelength on 80 meters.
Testing a vertical
Before the skyloop arrived, I did tests with the DX Commander. The DX Commander would have made it possible to have multiple resonant bands, on a single vertical antenna. As it is with vertical antennas in urban environments, noise was a greater problem than with a horizontal loop or yagi. As often mentioned on the blog/channel, weak signal work is very important and noise provents us from hearing weak stations. Unlike DXers operating from home, remote operators do not always have 100 watt radios, 500 watt amplifiers, or the battery capacity to run such a station. Therefore we need some gain on both sides of the antenna to get pulled in or pull them out of the noise. We also need to reduce that local noise as much as possible, so we can actually hear those weak stations. Unfortunately, a vertical can’t do that!
Another issue with the vertical was burying the necessary radial network under the backyard. This requirement was very unattractive (for my wife). We also didn’t want a wire mess in the yard for the dogs and unsuspecting people tripping over. Also missing from the DX Commander (and every other vertical antenna) was the reliable NVIS performance. As we say, “Use the right tool for the job!”.
Perhaps if there was a half wave end fed version of the DX Commander with more modest radial network requirements, it would be an option. So for now passing on the vertical option, and remaining firmly on the full wavelength loop concept for this station.
Skyloop testing and advantages over a dipole
The skyloop takes a considerable amount of property to put up. This is especially true for 80 meters. Its size is the price of excellent performance. The thing is, it doesn’t have to be set up in a perfect square. This gives us to deployment options the “antenna purists” might not even consider. In exchange for its size, we get a drop in noise level, gain over a dipole, and something which can easily be hidden in the trees. Here are three benefits of the skyloop over a dipole.
- The skyloop is an incredibly quiet antenna, reducing background noise and making it possible to work even weaker stations.
- The skyloop has more gain than a dipole.
- The skyloop provides better NVIS performance than a dipole at the same height
The image above left shows a traditional square sky loop antenna deployment. Unfortunately, the tree which could have supported that missing corner of the sky loop, was taken down last year. Not wanting to put up any other artificial structures for antenna support, a triangle would be a better bet. The triangle comes at a cost though! The square provides the lowest cancellation of local noise, with a larger inner area inside the wire. The triangle also has good noise cancellation, but not nearly as good as the square. Even so, the current plan for my own station is more of a triangle. The height will be somewhere between 10-12 meters (30-40 feet).
It could be higher, but using birch trees for support and living near the sea, wind is an issue. The tops of the birch trees swing quite a bit in our legendary wind storms. Supporting the skyloop midway up the birch tree, alleviates this issue.
Winlink Hybrid Network
For winlink email within Finland, 80 meters is “the band”. Almost all gateways in Finland are on 80 meters, with a couple on 160 meters and 6 meters. There are no alternate WARC band gateways. This is fine for high power stations, during non contest weekends, but can be challenging at the wrong time of day, or when operating at lower power levels. Since one of the goals is contributing to the Winlink network in Finland, 80 meters has to be my best performing band for this antenna. I’ll also need to come up with a quiet weak signal band, for low power work and/or for times when contesting is dominating 80 meters. Perhaps a 60 meter option later on. Supporting remote and low power stations off grid is incredibly important for this station. This means offering solutions to them, albeit outside of contest bands.
Just in case you’re interested, here is a playlist of my ongoing Asynchronous Communications for preparedness series.
The Context
As mentioned in other posts and videos, it is extremely important to be inspired to and inspire other operators to contribute additional resources to our networks. It doesn’t matter if we are talking about JS8Call, HFLink, Winlink, or any of the other network tools we rely upon. This over simply consuming resources others have deployed. Since most of my traditional ham radio activities are done man portable, my home station is generally underutilized. I do run a JS8Call station 24/7 on 40 meters. That is also sometimes augmented by an 80 meter JS8Call station. SSB QSOs or other contacts “for fun”, are generally done out in the field.
This means the home station is generally there for the EMCOMM and preparedness side of “the hobby”
The Skyloop installation is the first part of contributing back to the winlink network in Finland and surrounding countries. Other projects related to this are:
- Off Grid battery backup for the Winlink station
- Supplemental power generation
- Larkbox Mini PC
- Improved Monoband antennas for JS8Call
- Ham Shack renovation
- Vara FM Gateway
- …
The tower work for this project is being supported by Chameleon Antenna. Chameleon Antenna very kindly supplied their Skyloop 2.0 for this project. The CHA SKYLOOP 2.0 is an extreme performance horizontal full-wave loop antenna. The antenna is comprised of 80 meters (265 feet) of wire, insulators, and a matching transformer. I reached out to Chameleon after deciding on the right antenna for this project.
Here is the user guide.
I understand I could have built a full wavelength horizontal loop on my own. Not having practical experience on materials and longevity, I decided to leave it to the experts who understand antenna deployment in extreme conditions. After calculating the wire, toroid, winding material, enclosure, hardware, waterproofing, building this antenna myself, with the level of quality/reliability required at this latitude, would have cost much more than buying it from someone with expertise in this field.
I think this was a good decision.
73
Julian oh8stn
YouTube: http://www.youtube.com/c/oh8stn
Tipjar: https://paypal.me/oh8stn/1usd
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