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Welcome to SM0OFV's blog.
This is not an ordinary blog
that's being updated on a daily
basis or having the functions
of established ones, but more
like a place where I randomly
publish some of the stuff I do
or other things I find interesting.
Hence the -ish.
Last modified 2023-06-26
2023-06-26 -- Entry #7 -- Checking out crane cameras in the 5.6-5.9 GHz band|
The 5.6-5.9 GHz band is shared in various segments between license free, short range devices such as WiFi, drone cameras
and video transmitters as well as amateur radio and various other devices. One interesting use of analog video transmitters,
at least here in Sweden, is crane cameras. These appear to be used mainly to help control and align the winch.
As I'm also QRV on ATV at 5.7 GHz, I have various gear for this, and one cool unit is in fact a diversity receiver built into
a 7" screen togehter with a Li-Ion battery pack for portable operation. It's an OEM product called RX-LCD5802 which I
bough new from an auction site a couple of years ago.
In the beginning of the millennia, I was warspying/warviewing wireless cameras in the 2.4 GHz band, which was quite a lot
of fun. By doing so, I also stumbled across various crane cameras. However, the shared use of WiFi, and later also Bluetooth
in that band seriously interfered with the analog video signals to a point where it became more or less unusable. Soon a
migration to the 5.6-5.9 GHz band started. To be fair, some video equipment is still made for 2.4 GHz, but now use digital
modulation and FHSS to overcome the congestion of signals. There are WiFi signals in the 5.6-5.9 GHz band as well, but they
are far less problematic.
So, today, it's quite common to find analog crane cameras in the 5.6-5.9 GHz band at construction sites around Stockholm, and
most likely around the whole country. I'm quite convinced they can be found in other countries as well. So how interesting is it
to search for them? Well, it depends. Normally, there isn't much happening in the video except heavy lifting of construction
material, so the entertainment value is quite low. However, from an RF standpoint, they can be viewed upon as QRP TV beacons.
The law here in Sweden limits the power level for license free transmitters for unspecified use in this band to 25 mW EIRP.
This normally means a very limited range, but a crane is quite tall, and if you mount a directional antenna (patch antenna) on
the receiver, a crane can be received from several kilometers away. In other words, it's fun to check the propagation and do
range tests against them.
Here's a clip with video from two different cranes in Sundbyberg, just a few kilometers from my home QTH. Some slight WiFi
interference adds a bit of noise to the video. This can of course be overcome with a larger and more directional antenna.
2023-05-04 -- Entry #6 -- LNA "Lena", another NDB beacon
This NDB beacon is located in the countryside, a bit west of Stockholm. LNA transmits on 330 KHz with a power
less than 50 W and an intended range of 25 nautical miles (46 Km or 74.5 miles).
This time I opted for the slightly more spectacular view from a DJI Mini 2.
2022-12-03 -- Entry #5 -- ERK "Erken", an NDB beacon
Ever wondered what an aviation NDB (Non-directional beacon) may look and sound like? Well, I ventured into the
northern parts of Stockholm county just to show you all. ERK transmits on 383 KHz with a power less than 50 W and
its intended range is 25 nautical miles (46 Km or 74.5 miles), but it can of course be heard much further than that.
NDB DX:ing is a fun part of our radio hobby, but it's getting harder an harder to catch them as the manmade noise
increases and the number of active beacons decreases. These beacons are being replaced by more modern systems, and
several NDB's belonging to Arlanda and Bromma airports here in Stockholm county have already been decommissioned.
2022-11-16 -- Entry #4 -- SAQ Grimeton and UNESCO 50th anniversary commemoration transmission
Today I tuned in to the commemoration transmission from SAQ on 17.2 KHz. The 200 KW Alexanderson alternator
was built in 1924 and is the only one of its kind still in existance. For more info, go to https://alexander.n.se.
My receive equipment is quite simple. The antenna is a Procom BCL-1KA active antenna (older version), connected
to an AOR AR-5000+3. As I live in a city, the interference level in the lower HF spectrum is ridonculous. Todays
transmission was barely audible, and I could only hear a few parts of the message. I really wish I had a Wellbrook loop
on a rotator now ;-) Here's a short clip to give you an idea of the incredible hash level basically drowning SAQ.
The interference level has unfortunately risen dramatically here over the last couple of years. I've noticed this across
the whole lower HF spectrum, mostly affecting bands below 7 MHz. For comparison, here is the SAQ christmas
transmission from 2016, received with exactly the same equipment as above.
I estimate that the manmade noise level on 17.2 KHz was at least 20 dB lower here than today. Hmm...
2022-11-16 -- Entry #3 -- Artemis 1 successfully launched today
It finally launched at 06:48 UTC this morning! So, did you know that there is ham-related hardware onboard? The Japanese
Omotenashi payload consists of an orbiting module and a surface probe. Both will communicate in the 70 cm band, and with
adequate gain in your antenna system, you may actually be able to receive one, or maybe even both of them. For more
information, check out JAXA Ham Radio Club and NASA:s site.
2022-11-11 -- Entry #2 -- Fascinating VFO mechanics
A while back I had to repair an old Yaesu FRG-7 which had a number of faults. One of them was a broken/stuck VFO.
I was fascinated by the mechanical construction, so after repair and lubrication I made this clip.
2022-10-23 -- Entry #1 -- Blog start and old photos
After running RigPix for more than 22 years, I thought it was time to share something more than
equipment data. So, I decided to start some sort of blog where I can publish various stuff every now
and then. I do not intend to make this a regular routine, but more like a random thing when I have
something to share and time to spend doing so.
I obviously do not use any special blogging software, but will hack HTML with Notepad as usual ;-)
With that said, let's begin...
Today I was sifting through some old photos from my earlier days as a radio nut, way before Rigpix.
Here are a couple of them, with comments.
This is the shack in my first own apartment which I moved into in 1983. The picture is actually from 1984, and I apologize for
the horrible quality. It's very difficult to see, but from left to right I had an Icom IC-201 for 2 m allmode, a Kenwood TS-820S
for HF and a National NC-240D for casual HF BC listening. It was mostly parked on 1440 KHz, which of course was the
frequency of the world famous Radio Luxembourg.
Above the TS-820S, I had a Colonel 2000 CB radio, which was the last of my gear for that band. I took my ham license in
1983 and completely lost interest in CB, but kept the Colonel a few more years for nostalgic reasons before I finally got rid of it.
The shack was located under my loft bed in this single room apartment during the first years.
This was the roof of the house where I had my first own apartment. From left to right is; a Hy-Gain 18AVT/WB HF multiband
vertical with a VHF band III yagi for TV-DX:ing beneath it, a TV and FM setup that belonged to the house, a rotatable mast with
a Cue-Dee 15144AN 15 element yagi for 2 m and a Cue-Dee 17X432AN 17+17 element crossed yagi for 70 cm above it, and
last but not least, a Mosley TA-33 Jr HF yagi. The latter had not yet had its rotator mounted on this picture.
This setup lasted from around 1987 to 1990 or so.
This is part of the shack from roughly the same period as the antennas above, maybe around 1987 to 1989. It has now moved into the
kitchen, which meant I gained a tad more space. The radios seen from left to right is; a Kenwood TS-430S, a Kenwood TW-4000A
and the Colonel 2000. The latter two powered by an Alpha Elettronica AL 622 regulated power supply.
I was computerized in 1983 with a Spectravideo SV-318, which was quickly replaced by an SV-328, which in turn was completed
with the large expansion box and all plug-in cards. And no, despite the endless software availability of the C-64 and other popular
machines at the time, I remained faithful to the Spectravideo gear with its Z80A CPU and more elaborate design.
The picture shows the slightly newer Spectravideo gear I had at the time. An SVI-728 with floppy disk expansion and the somewhat
weird SVI-838 X'Press 16. It was a hybrid between MSX2 and PC with an Intel 8088 CPU that could run MS-DOS 2.11 and CP/M.
I acquired it around 1986, and this was my first step into MS-DOS.
Other equipment seen here is a CDE AR40 rotator, a Heathkit HD-1410 keyer, an SSA Key and a Kantronics KAM. I got interested
in packet radio in 1985, and as I also wanted to demodulate RTTY and other signals, the KAM was my #1 choice. All my Spectravideo
computers have had a serial port of some variety, so they were very easy to interface with the KAM.
Not visible in this picture is my TV-DX equipment, which was located to the left of the terrestrial globe.
This is the view from my balcony in 1988 with the base of a homebrew co-linear for 2 m visible, and a homebrew GP for 70 cm
barely visible below it. The area with the blue hi-rise buildings in the background is inofficially called "Blåkulla", or "Blue hill"
The school on the street below is called Hagalundsskolan, and my dad actually went there for a year or two in his early years.
This is my shack in late 1989 or so. The TW-4000A has now been replaced by a TR-751E and its companion TR-851E. A nice
Daiwa PS-30XMII regulated power supply has also been added. To the left you can also see the TV which is a part of my TV-DX
equipment. And for you younger broadband internet folks, can you spot the ancient 300 baud dialup modem?
This picture is most likely from 1990. Now I have supplemented the shack with a Barker & Williamson VS-300A antenna tuner
and a Sky King SU-2000 rotator. Here I am experimenting with homebrew repeater logic. I constructed it with TTL-ICs and a static
RAM. For on-air testing, I hooked it up to an Icom IC-R7000 and the TR-751E. It worked beautifully, complete with courtesy
beep and ID. At the time, we had very stringent rules for owning and managing a repeater, so the project was never completed.
This is my 1997 shack. I have now moved to the three room apartment where I still live today. On this picture, I had a whole room
to myself where I could enjoy the hobby. The shack here consisted mostly of Icom gear like IC-275H, IC-475H, IC-735, IC-R100
and an IC-R7100. The desk mike is an Icom SM-8 which I bought new in the 80's, and still use today.
My squatting in this room would prove to be short lived as there were kids in the making.
So, now we needed a nursery for our kid, and I had to vacate the nice room where my shack had been for about a year.
The decision was made to sacrifice a piece of the livingroom where I could build myself a new shack, although pretty
small in comparison.
Skipping 11 years to 2009. After separating from the XYL late 2004, the kids lived with me 50% of the time where they shared
one room while I had the master bedroom all to myself. The main shack still remained in the livingroom. However, I wanted to
be QRV from the bedroom as well, so I ended up with this ridiculous setup.
From top to bottom: Kenwood RC-2000 remote control panel, Uniden Bearcat UBC-780XLT, Yaesu FRG-9600 and VR-5000,
Kenwood R-1000 and TS-2000. Madness I tell you! Madness!
Jumping to 2012. Ham life is chugging along. This is what the livingroom shack looked like during this period. As stated above,
this shack was fairly small, and the bench was normally cluttered with all sorts of projects and tools. I did tidy it up for the camera
The station here consisted of: Icom IC-756 Pro II, IC-970E, IC-E2820, IC-R9000, Kenwood TM-D700E, TS-790E, Standard AX-700,
Yaesu FRG-9600, Sommerkamp TS-789DX, Cobra MR-F55 EU and homebrew equipment for 23 cm ATV.
Some accessories included Yaesu G-400RC rotator, Icom SM-8 and Kenwood MC-60 desk microphones. On the far computer screen,
I am running a satellite tracking program as I occasionally listen in on various signals from space.
To end today's entry, this picture shows some of the antennas on the roof in 2012. The rotatable mast in the foreground carries, from
top to bottom: Cue-Dee 17432AN 17 element yagi for 70 cm, Tonna 220623 23 element yagi for 23 cm high band side-by-side with
a 220624 23 element yagi for 23 cm low band (ATV) and a Cue-Dee 15144AN 15 element yagi for 2 m.
To the right you can see a Comet CA-2x4 MaxN co-linear for 2 m/70 cm and the top of a Comet CA-1221S co-linear for 23 cm.
Well, that's about it for this time. Please check back later as there will be more material here in the future.
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