KN2M Remote Station
Hi. This paragraph is about the KN2M remote station. About 20 years ago, I lived in a city QTH with a really nice motorized crank up tower and a home brew multiband yagi on a 40 ft boom. Infact my old friend W2PV, the late Jim Lawson, was the inspiration for the antennna. It was of my own electrical design. My neighbors hated my antenna and my operation. I had to move to another home. I am sure they had a party when I left. In order to keep on the air, I found a country property with enough land and have two 140' Rohn 45 towers. The station was started in 1991 and the towers are basically unchanged but almost every feature inside is upgraded or modified to be remotely controlled. The station has stacked yagis on 10, 15 and 20m. Each antenna is independently rotated and selected. There is a 4 element 40m antenna and a new stack of three Skyhawk triband yagis. Lightning and winds are a constant problem. The location is very harsh in the winter and we have frequent unrelenting winds over 80 mph. All the yagis have been replaced over the years due to wind damage. In fact, early attempts to keep up the 40m antenna met with quick failure from wind damage twice in the first year. Now, all the antennas (except the Skyhawks) are either my own electrical and/or mechanical design. I worked with M2 Antennas for the construction. At this time, using antenna construction software that I wrote, I have to say there have been no mechanical failures of the newer yagis. Each feedline has lightning protection at the base of the tower and there are two main underground hardlines connecting the tower switching houses to the main house. Lightning protection is also located where the hardlines and each and every control line enter the house. Since it is 500' from the station to the 40m yagi, I do not control the ring rotors directly from the station but with remote power supplies and separate relays in small buildings at the base of each tower. The buildings also house RF switching between the hardlines to the various antennas so everything is pretty much out of the weather. All together, there are several miles of underground control wires, coaxial cable, ground radials and a perimeter ground around the house. About 10 years ago, I started experimenting with remote operation of the station. We have two station positions, a left and right. My wife, N2HIW, is also a ham operator. She was photographed at the right station as "Miss April" of the CQ Calendar a few years ago. The two positions are isolated with bandpass filters and are interlocked so that two transmitters can not select the same antenna at the same time. The left station is set up for SO2R with a Yaesu 5000, an IC781, an Alpha87A and an AmpMaster. This station is primarily used for contest operation. The right station has a FT1000MP, an IC781, another Alpha87A but this station also has a TenTec Orion on a separate desk. This station computer has a fixed ip address with my computer router, along with the KN2M packet cluster (kn2m.d2g.com). The Orion has been my remote transceiver for remote operation since day one because it was the first completely controllable transceiver by computer. I have experimented with Icom but, decided against it as they remain the only manufacturer that does not provide computer code for RIT function and I love to operate CW. We may move to the Flex system in the future. For now, the station uses N4PY software. I use separate audio software, like EyeBall Chat or IPSound or Skype to transmit the audio. I added control software for the Alpha87A and I hired a software engineer to write windows code to control the Alpha Digital switches. At first, all I had was a simple multiband dipole antenna and no antenna switching. Then I added a single triband antenna. All this sounds pretty average so far and not too spectacular. The best feature of the station and the point that makes me say this is about the most complex remote station in the world is that all of the antenna switching, including control of the stacks and listening antennas are remotely controlled. In addition to the eight rotatable yagis, a SteppIR DB18 (non-rotatable), we have a 4 Square for 80m, several delta loops and dipoles for transmit. On receive, there are beverage antennas, a K9AY loop and a DX Engineering 8 position steerable receive antenna and a switchable preamplifier. Each and every antenna that can be used locally is controlled by remote computer function or normal manual controls. Typically, we keep the manual controls at the left station. The interfaces took some time to work out and I had help from my friend N2EJT for the work over the years. Some of the interfaces were accomplished using Alpha Digital Antenna Switches (DAS, no longer made), like phasing the yagis or switching the 4-square. In other cases, we designed and built advanced logic interfaces to adapt position controls, like on the DX engineering steerable array or the K9AY loop. The biggest problem is an occasional lockup on the station computer or the cluster machine. We now have a telephone answering machine that will restart the computers if either computer goes down. We have backup power at each computer for about 30 minutes. My preference for remote operation is CW. I typically use the keyboard in the N4PY software to send CW. I know many times DX stations are confused by the rate I come back to them and keep calling me. It is slower than a hand key for some operations. If you find me on the air with SSB, I am likely at the station, but if CW there is a good chance I am running remote operation. I also have a SteppIR vertical at my new city QTH in Buffalo. This is a very neighbor friendly antenna and I find that is a super DX antenna for having fun when I do not want to put the remote station on the air. When on vacation, if I have an internet connection, I can put the station on from anywhere in the world. 73 and good DX.
80 m FCP Inverted L Four Square!
Last year I began to experiment with inverted L antennas using the FCP (Folded Counter Poise) instead of radials or an elevated tuned radial system. I started with the IAC Inverted L Bazooka for 80m and constructed the FCP based on K2AV recommendations on this web site. I used 1/2" PVC for the spreaders. I was hoping the 80m antenna would work well without radials and I was pleasantly surprised. I worked Hawaii easily barefoot with this antenna. Most importantly, the antenna provided an almost perfect 50 ohm match and was easy to tune by adjusting the horizontal end wire which needed to be folded back about 10'.
The IAC antenna was perfect for the installation. It was well built and attached to the transformer with minimal difficulty. As far as I know, I was the first ham who used the IAC with the FCP concept. I oriented the FCP at right angles to the horizontal wire.
Stimulated by this success, I purchased another IAC Bazooka L for 160 m, constructed another FCP. I did not have a great location for the 160 m version and needed to lengthen the horizontal radiator by about 15' in order to match it at 1830. Again, I was able to work significant DX, including many European stations barefoot.
I then turned my attention to the 4 Square array I had located at the remote station. I used a dipole array (visible in some of the photos) and it never was satisfactory except for the first few months it was up. The antenna suffered from numerous failures of the wires, broken coaxial feedlines and the phase box required mounting at the 90' level of the tower, making it difficult to service or test. At this point, I had all but decided to to remove the array and replace it with a ground mounted Four Square inverted L using the FCP as I did not want to place hundreds of radials in ground. The array location was near land that was still wooded or never cleared. Ground radials would have been difficult to install. Basically the whole antenna is located on a patch of land about 80' X 80' without radials. I used 4" timbers to hold the FCP. I located the antenna on my property to provide optimal signal to EU and South America based on models I ran with EZNEC. There IS interaction with the towers and especially the 160 m Delta Loop to the Southwest direction. The model clearly shows that a center metal support has little effect on the pattern, the antennas really do not have to be that level and the horizontal wire can have some upward angle or sag without much effect on pattern. The vertical portion of the element was changed from 30-35 ft with little effect. In fact, the only thing that will really mess the pattern up with the ground installation seemed to be an antenna plugged into the wrong port or a phase angle problem inside the box.
Because I had so much success with all my yagi antennas from M2 Antennas, I contacted them to help develop the mechanicals for the prototype antenna elements. I studied the necessary tapers because I wanted self supporting elements and center support. We decided on mounting the antennas to 3" schedule 40 galvanized pipe using a custom made tilting base. A standard 2" gin pole is then mounted to the pipe and a rope passes through the pulley to pull each element up. The gin pole can be moved from one element to the next in a few minutes. Raising an antenna is a two man job but is pretty easy as seen on one of the videos of the process on my youtube site. I oriented the element mount so they all fold down towards the center support where there is clear land. Each FCP is is oriented at right angles to the horizontal wire of each radiator. A central mast of 3" aluminum tapers to a 2" fiberglass top hat with a custom made pulley for each of the four wires and ropes. I put a weight on each line to allow the wires to drop to the ground and allow easy adjustment or tuning. Each horizontal wire turned out to be 47' in order to match the array for 3525. The array has 95' diagonal spacing to the far corner. A single element performed quite well. I tested this before the remaining elements were constructed or added to the system to be sure the design was working. One evening I worked ME using 10 watts after a CQ call. That was about 400 miles distance.
I have a machine shop on site and this was very valuable to manufacture parts or change the system as ideas and thoughts came up. For example, I made custom bearings for the pulleys and sleeves for the top element section. This allowed one to telescope a 1.5" section into the 2" top for further adjustment if one wanted to make the vertical portion taller. The vertical radiator starts with 3" tubing and tapers to 1.5" with an eye bolt at the top to attach the horizontal wire. Tuning the array was done one element at at time with the horizontal wires of the other three radiators lowered and with their FCP disconnected. After the other radiators were raised resonance dropped about 500 kHz and the horizontal wires required shortening by about 3' and this provided a near 50 resistive load to the Comtek Phase box. I also discovered that one could fold the end of the horizontal wire downward, if necessary, to lengthen the wire for additional tuning effect of a single antenna but this was not necessary in the final array configuration. It is important to use identical coax to the individual elements. We verified identical lengths using a network analyzer but simply cutting the 4 lines to the same length is suitable but a velocity factor of at least 0.8 is required in order to have the physical cable length to reach the phase box at the center support. One thing I did learn was the 9913F7 cable had the highest VF and it easily reached the center box. I used 50 ohm cable as the antenna is similar impedance. After a phasing problem with the Comtek box was identified and corrected the system played very well. Although cut to 3525 and designed for 3600 the antenna allowed for several EU QSOs at around 3800, including EC4DX, which was arm chair quality. This was a first for my station. In Europe stations reported a 15 dB loss of signal when changing direction to the SouthEast. On receive, I noted up to 4 S-units difference on F/B or F/S depending on conditions and the station I was listening to. Finally, I want to clearly indicate the antenna is one of the few that I know of to incorporate the FCP with a 4 Square design. This is not intended to be superior to a system with complete radials but it is very convenient to install and if interested parties require additional information on my prototype they may also contact M2 antennas, in addition to the K2AV web site above. I used the Comtek box because I had two on site, but I believe the product by Array Solutions is even better.
The photo above shows the completed array. Each element has one or two timbers to support the FCP. The center support has a black plastic garbage can covering the phase box and dummy load. As you can see it just about fit on the property and goes up to the woods, where placing ground radials would have been very difficult.
I have some videos working on the towers and putting up the SteppIR DB18 on YouTube. You can find them in the link below.
The DB18 is compared to other antennas on 20m and 40m also. On 20m CW HL2DC is calling CQ. I had just worked Lee barefoot. I switch between the stack, Skyhawk and the DB18. The SteppIR is a bit off direction but as you see there is a major improvement in signal between the stack and the other two antennas. Sometimes there is minimal difference depending on propagation. I think most hams have not had the opportunity to listen to comparisons like these.
On 40m CW, Hiro JS1NDM is on in the early morning with a great signal. I am comparing him between the 40m monobander in the photo below and the DB18 below it.
The link is:
I hope you like the videos. Here are some photos of the antennas, starting with the SteppIR mounted at 110': The 40m monoband is above and the Skyhawk is below.
This is an older photo of the South tower, showing the ring rotors, the 4 Square for 80m, the Skyhawk and the two 10m antennas. The 10m stack has now been relocated on the front tower and is fixed into EU. The antennas were replaced with two more Skyhawks and all three are stacked using a StackMatch. The small building holds the custom switching necessary to turn all 8 rings with a single controller, terminals for the control wires and the coax switching. Keeping this indoors really the weather from affecting the connections. We have electricity in the buildings and WiFi.
This next photo shows the North tower with the 15 and 20m stacks. The antennas rotate and operate in pairs or individually.
Last modified: 2013-08-25 22:47:59, 15671 bytes cached
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