Introduction
In the 1995-2006 timeframe we lived in the village of Opmeer, where local QRM and lack of space formed a huge problem as far as low-band DX-ing was concerned. Our house in Opmeer was surrounded by households containing TV-sets, computers and other electronic equipment producing an average S7-S9 level of interference within the 80-meter band.
Birds-eye view former home-QTH, Opmeer
This situation and the desire for low-band DX-ing made me look for alternatives.
In the fall of 1997 I stepped on my bike and drove around the rural area around Opmeer, looking for a farmer who would allow me to set up a station on his land. After some ten or fifteen "No Thank You" I met family De Jong, who were genuinely interested in my plans. And, to make a long story short, they allowed me to use their land in the winter season.
Birds-eye view of the Cees & Ans de Jong farm, Hoogwoud
DX-season '97-'98
Quickly I bought myself an old road workers-toilet, that was to become the "shack" for my experiments in the '97-'98 season ...
There we were: a shack on a tremendous location! Plenty of space around, no QRM and no neighbours complaining about LFI.
A beautiful day in August '97
At the left, under the canvas, a surplus generator providing 230 Volt (more less...) Hand-started, petrol-fed. The 20 meter vertical is also surplus. Double-guyed, consisting of 10 2-meter segments being cranked up by a single person?!
Around the shack both barbed-wire (summer: cows!) and a fence (winter: sheep).
Sunset!
The vertical, 20 meters, was fed against only two shortened radials of 10 meter each. The two of those were electrically lengthened by a common coil. This technique was used to force equal currents in both radials, despite differences in length.
For reception I used 4 bi-directional beverages, each about 2.5 wavelengths long, in the four main directions: North-America, ZL, JA, South-America.
The amplifier (700+ Watts)
The radio used was a FT-900, that was carried along on each of my "trips" to the shack; I was afraid it might got stolen if being left unattended. For the same reason I build a cheap-and-ugly Amplifier that could stay in the shack.
Close-up ..
DX-season 2004-
My DX-season '97-'98 project came to a sudden standstill early '98 because of a tremendous storm that blew away the shack...
Having experienced the advantages of no-QRM and beverage-antenna's, I started wondering about another way to have a good DX-situation, while at the same time avoiding the discomfort of nightly expeditions thru rain and storm...
It took me a couple of years to work out an alternative, being helped by progression in computer-technology.
At the end of summer '03 my plan was ready: a wireless TCP/IP-link between Opmeer and the remote farm would enable me to control my remote radio and antenna's, and at the same time make it possible to transport (digital) audio to- and from it.
This WiFi-link would serve another purpose as well: the family that was so kind as to let me use their land could have unrestricted internet-access using the same link ;)
So, pacific wireless antennas both in the tower at our house in Opmeer and on top of the haystack at the farm and the link was there!
WiFi-antenna 17 meters Up!
At our home-QTH in Opmeer, the WiFi-antenna was mounted in the tower at a height of 17 meters, just underneath the FB-33 HF-beam. Note the black-box just behind the WiFi-antenna!
This box holds the DLink WiFi-modem. As I found out in the course of this project, modem and antenna must be interconnected with the shortest run of cable possible! So, it's UTP-cable running from the shack to the top of the tower..
It was quite a job to get the antenna in the right direction; the opening-angle is very narrow, and besides a rough indication thru the use of a map and compass I could only use trial-and-error to get it pointed out OK. "Trial" meaning lowering-and-raising the complete tower over-and-over again..
And one at the farm ..
At the farm the WiFi-antenna is located about 12 meters from the ground. To direct this one to the antenna at my home-QTH was easy, because I had a line-of-sight to the latter.
One of the (switchable two-wire) beverages
Again, like in the '97-'98 season, beverage-antenna's are used for reception of low-angle (=DX-) signals.
Two of the (two-wire) beverages are placed just along the side of ditches. Cows and sheep don't come there, meaning those antenna's can stay there almost the entire year.
The other three single-wire bi-directional beverages run across the field and can only be present during winter time, when there's no cattle or only sheep around.
The new shack
The new shack is a lot better than the old road workers toilet I used winter '97-'98. I painted it dark-green, so environmentalists would not start complaining about it. The shack is situated alongside a floating-roof tank for manure. In the middle of the picture you can just see the wires running mains and TCP/IP to the shack. The "tower", attached to the tank, holds up an FD-4 windom-antenna used for transmitting on HF, plus a Diamond X-50 2/70-meter combi-antenna. The latter is used for transmitting the audio-output from the HF-radio on 144.987.5.
The VHF-transmitter in the shack can be activated remotely via the WiFi-link, and was used a lot when the VoIP-connectivity between home QTH and remote-shack was not yet there.
In the shack
To the left you can see a (locked) steel cabinet, containing the radio (Kenwood TSB-2000) & 25Amp power-supply. On top of the desk there's the XP-computer that can be remotely connected to via XP's "remote desktop". The computer supports "wake-on-LAN": when I want to DX, this computer can remotely be switched on via the network. The computer also runs "Skype" for transporting the radio's audio to and from the remote operator's PC.
To control the radio Ham-radio-de-Luxe is used. This superb (and free?!) program supports all functions of the Kenwood radio, and furthermore offers functionality to switch external devices (like antenna's) using the computers' parallel-port.
Antenna-switch
The home-brew device shown in the picture above forms the interface between the XP- parallel port and another unit where the 75-ohm coax feeds from the three beverage-endposts are switched to the HF-radio. In brief, this hardware lets me use HRdL to select either one of the end posts, and enables me to select one of up-till-three beverages available on that endpost. (Thanks to John Devoldere ON4UN for the idea of using the centre-conductor of the coax to feed either a positive-, negative- or zero-voltage to the endpost for switching relays).
Beverage antenna endpost
Using two high-mu ferrite-cores and two relays, it's possible to switch a two-wire beverage in one of two (opposite) directions. The cover of the box shown is from transparent PVC; handy when you want to check for damage when the thing isn't working properly, for example because of a strike of lightning.