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Vassfjellet season begins

Our beacon site at Vassfjellet has been a topic for many blog posts in the past. It has been one of our favorite pastimes, so naturally we were excited when the snow finally started melting. At last we are able to access the site again, and are eager to see what needs to be fixed this year.

The season was kickstarted when some of our extra-eager members, LB0VG and LA2QUA, went for a winter trip there to make some quick repairs on the wifi link, and assess the health of the site in general.

LB0VG returned to the site again this Saturday. He was able to make this trip by car, which makes it much easier to haul equipment to and from the site.

The goal for the trip was to install another wifi link, this time to act as a failover for the first wifi-link. The failover link will take over once the main link dips below a certain threshold. This way, we have a method of securing continuous operation for our beacons and monitors in case of trouble.

LB0VG aiming the Ubiquiti PowerBeam for the failover wifi.

The failover link still needs some alignment to make perfect contact, but we are sure that it will work after some more tweaking. Once it is operational we are eager to detail the nitty gritty technical details on this blog.

The only technical installation that broke this year was our ADS-B antenna, which had gotten bent 90 degrees out of shape. Luckily this was rapidly repaired by LB0VG, and our ADS-B station is now back to receiving DX-like distances on passing aircraft.

ADS-B antenna 90 degrees out of shape.

Other than improvements to existing setups, the main theme for this years Vassfjellet adventures will probably be repairs to the building structure. Over the last couple of years, we have made small repairs to various things (mostly the leaky roof), but have noticed some problems that will need a more thorough refurbish. The main problem that we need to address is that the cabin has started to slant significantly, leading us to think that the foundation is compromised. Also, the roof is leaking again. 🙂 We will come back to these issues in future blog posts.

Vassfjellet remote access: part 2 – IoT-stuff and more woes

In the last iteration of this blog series, we talked about what equipment we utilize to bring Internet up to our cabin on Vassfjellet. This time we’ll talk about some of the equipment that requires said Internet connection, and why we have chosen to place it up on a location that’s practically left inaccessible half of the year.

Picture before moving the 5.8Ghz-antenna earlier this year.

The two most recent parts of the setup are a couple of webcams serving us environmental pictures for observing the mast, plus giving us a brief overview of the general weather conditions before travelling up there. Even though their field of view suggest them being installed rather hastily, we haven’t had any major problems with them up to this point. We have a server collecting pictures from the cameras throughout the day, accessible here.

The other rather scary looking camera is seen on top of the mast, with the 5.8Ghz-antenna right below.
Our second camera – the rather crude mounting still seems to be holding up.

Two other installations we maintain are a couple receivers; one for ADS-B and a AIS-station. The latter had its antenna crushed last year, and has been temporarily installed with a small VHF antenna for the time being with rather poor results. The former unfortunately has suffered a similar fate this winter, as the antenna was blown or torn off. Luckily we now have cameras to confirm the rough environment our equipment is exposed to each winter. Yikes.

A little crooked, but still there…
…aaaand it’s gone.

Another point in the installation is that Ethernet and high-power VHF and UHF transmitters don’t necessarily coexist together that well, especially when the antennas are positioned inside, along the wiring. We’ve encountered a number of dropouts on several points in the setup, some where all of our equipment has been left disconnected for longer periods of time.

Unstable connections to the camera are usually presented like this.

We tend to experience this phenomenon on longer Ethernet-cables, one of which has been the uplink for our second switch. Through the management interface we have been able to locate the flaky connection, and although it doesn’t confirm our theory of RF-interference, it certainly is helpful in in troubleshooting the setup over the Internet. Luckily the radio-link down to Samfundet still has remained working, which means we could eliminate any theories of power loss or other more serious fates to our equipment.

Pictured is the switch serving one of our cameras and the two receivers.
Although not the prettiest setup it still remains working.


Since the first post we’ve had some time to monitor the stability of the setup, and while not as stable as hoped, we have still been able to reach our equipment most of the time. There has been a recent visit to help solve the aforementioned issues, and by removing a troublesome switch we hope to have a lasting connection to our equipment throughout the winter.

Planning a trip to Vassfjellet in December is a tough call –
but some are crazy enough to do it for saving the sacred uptime


During our last visit in October we also installed a Linux-host and a relay-box, assisting us in turning on and off the beacons if needed. We connected it to our IRC-channel, and are notified there every time the network is down at Vassfjellet. We have only tested this briefly, and will be talking more about it in another post.

The tiny Linux-host, doing its thing.

The plan for next year is to remove most of the longer cables and replace the remaining ones with fibre-cables to remedy any potential for noise pickup. We also plan on adding more monitoring for our beacons, and are considering more equipment for gathering data about the weather conditions. More to follow!

A recent video explaining why being a antenna at VFJ is a strenuous task.

Vassfjellet remote access: part 1 – the link

As mentioned several times on our blog, we have a cabin up on a mountain top called Vassfjellet, sometimes referred to as VFJ. This cabin houses all our beacons, which provide amateurs all over the world the facilities to check band conditions towards Europe and other countries in reach.

The antenna at our QTH. The radio right behind it was used only for testing.

In addition to the beacons, we have also put up a 5.8Ghz WiFi-link to provide the cabin with internet access. This point to point link starts all the way back at our main QTH, Studentersamfundet. This is a fairly long stretch, and shooting the link through an urban environment adds additional challenges. The link margin is quite low because of this. There are a number of devices in our cabin which require a internet connection to operate, including an ADS-B and AIS-reciever, and more recently a couple of cameras and a relay-box.

The fairly long link, 18km in length

The cabin was mostly without any internet access for the duration of 2018 and up until early 2019. The main culprit was the enclosure we had chosen to put our wireless radio in: it was too waterproof. The problem was that when rainy weather and melting snow came, water followed the wires through the enclosure and to the radio, slowly filling the enclosure with water. We speculate that the radio was left this way for the majority of its time, as the end result didnt seem to prove otherwise.

Definitive signs of water. Photo: LA1WUA
Melted RJ45-connector, arguably not the best smell

Needless to say, the radio was as dead as it looked. The soloution for this could have been rather simple; by drilling holes in the bottom of the box we could have let the excess water drip out instead of flooding the radio. Luckily we had another backup radio, and used that to re-establish our connection to Samfundet. But lesson learned – proper care and attention will be taken the next time we mount anything outside up at Vassfjellet.

The new setup, consisting of the Rocket M5 radio, a heavy-duty Ethernet-switch and some power supplies. Please excuse the poor wiring.

In our next try, we decided to mount the radio indoors, again. The reason we wanted the radio as close to the antenna as possible the last time, was to minimize any output loss through the cable. The ‘old’-setup had RG58-cable feeding the antenna, which at 5m in length gave us a pretty low amount of power radiating out of our antenna. This time we went for a much better coax, and moved the WiFi-antenna to the other mast that was set up for the new beacon antennas in 2017.

The empty mast and WiFi-antenna, ready to be joined together

We are unable to recall whether or not moving the antenna increased the signal at our QTH, but we can report having no problems with it so far. That is, except for a few configuration mishaps that required us to take another trip up to the cabin. In the summer and early autumn this isn’t too much of a problem, but during winter and early spring we keep our trips to the mountain at a minimum.

“Risk of falling ice”

The conditions during the winter usually lead to ice forming on the 200m high mast right beside our cabin, which makes it a real hazardous operation to perform any maintenance here during the season. Driving up here usually is no-go due to the huge amount of snow usually present during the winter. This only leaves us with half of the year to actually visit the facilities, and requires us to think forward for any problems that might occur during the winter.

One last look at the cabin before leaving for the next season

This time we tried placing any untested projects up inside the cabin so that we have the winter to check for any flaws or conditional issues before deploying them fully. In a coming post we’ll get to the equipment we have behind the WiFi-link at Vassfjellet, including two web-cameras and a relay-box planned to control the beacons.

LA2VHF/4, LA2SHF and the WiFi link restored at Vassfjellet

One month ago, we went for a roadtrip to Vassfjellet in order to install LA2SIX, our brand new radio beacon. Unfortunately, the mountain was not ready for us quite yet, and we were defeated by a large pile of snow in the middle of the road. LA2SIX had to be left behind while we made for the summit on foot. There, we discovered that one of our existing radio beacons, LA2VHF/4, had lost its antenna sometime during the winter and that the antenna wreckage was unusable.

Luckily, we have very good friends at Comrod who have been able to assist us. LA1BEA, veteran ARK slugger, happens to be the technical chief at Comrod, and he was able to supply us with a replacement antenna. Armed with the antenna and new hope, we could finally set out for Vassfjellet one more time last Friday.

The beacon rack is getting crowded.
Photo: LA1WUA

Our ambitions had increased beyond comprehension during the one month’s worth of waiting time: Not only did we want to fix LA2VHF/4 and set up LA2SIX, we also wanted to finally set up LA2SHF again, which has been down since October, and to reinstall our internet link between Vassfjellet and Samfundet, which has been down for such a long time that it has almost not been mentioned at all during the existence of this blog. Would we succeed with everything? Almost! We managed to get three out of four.

LB0VG and LA2QUA installing the replacement antenna base.
Photo: LA1WUA

With the new antenna in place, we eagerly connected the 6 m and 4 m beacons. LA2VHF/4 worked without issue, but LA2SIX only managed to send a series of “dit-dit-dit-dit-dit”. This indicates that the firmware is acting up, and that deployment will have to wait a bit longer until we can fix the issue.

The next thing on the agenda was to restore operation to LA2SHF. This beacon had developed a nasty sideband, caused by injection of the LA2VHF/4 beacon into the 10 MHz reference. A local radio user was impacted negatively by this interference, so the beacon has been out of service since October.

In the meantime, we have been able to work around the issue and reduce the nasty sideband. We also decided to steer the null of our antenna in such a way that the local user is impacted as little as possible by the radiation from our beacon. We’ll give the full details of the sideband issue and the fix in a future blog post, but for now we are happy to announce that LA2SHF is up and running again.

LA3WUA controlling that the antenna null is positioned towards the local user.
Photo: LA1WUA

The final thing that we did this weekend was to restore functionality to the 5.8 GHz WiFi-link that provides data transfer capability to our beacon site. Now we will soon be able to have services like ADS-B up and running again.
The WiFi link, though having been down for the last couple of years, is a nice piece of engineering which we plan to describe in a future blog post.

LB0VG installing new coax for the WiFi link. Photo: LA1WUA

A big thanks to LA1BEA for helping us out with the new antenna. LA2SIX will hopefully be fully serviced this week, when it is up and running we will come back with an update. Getting three out of four fixed is much better than our usual Vassfjellet score, so we are very satisfied with this.

More photos from the trip may be found at
http://bilder.la1k.no/vjf-juni-2019/.

The annual “spring trip to Vassfjellet leads to discovery of broken beacon” blogpost

This weekend we finally had the opportunity to go to our beacon site at Vassfjellet, as the snow had thawed at last (or so we thought). Our plans were to install the newly constructed 6 m beacon, LA2SIX, and assess what had happened to the site over the winter.

We have not been able to hear LA2VHF/4, our 4 m beacon, for a while. This was disconcerting, as it might mean that the antenna which we planned to co-use for LA2SIX had suffered some damage during the winter.

100 m from the summit, we encountered the first and only pile of snow on the road. Unfortunately this was enough to foil our plans, and the rest of the trip had to be made on foot.

ARK’s beacon cabin.

Once we reached the top, we were surprised to find that the vertical VHF antenna was missing. Luckily, some passerby’s had placed the antenna in a secure location nearby, so we were able to retrieve it.

Apart from thorough carbonization of base and antenna contacts (probably due to beacon transmissions during the fault scenario) the antenna seemed relatively intact. The failure seems to have happened due to our lack of maintenance on the set screws which keep the antenna from unscrewing itself in heavy vibraton/wind. Nothing bad to say about the antenna, though, as it lasted 7 years without maintenance in conditions that have proven themselves extremely harsh.

We attempted to clean up the antenna as best we could, and re-installed it on the base. Our efforts were in vain, however, as the antenna reported more than 10:1 SWR across the band.

Antenna analyzer result is a textbook example of bad SWR.

Unfortunately we need to announce that LA2VHF/4 will be temporarily offline while we perform repairs to the beacon and antenna. We have brought LA2VHF/4 back to the lab bench for a thorough examination, since transmitting into an open load for an extended period of time is bound to have caused some damage to the finals.

We have set plans in motion to be able to fix both beacons, hopefully in time to get the most out of this summer’s sporadic E season. We hope to return soon with an update on this matter.

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