Cutting-edge diy projects
I was cleaning up the basement, and found a box with my old pictures. This one brought me fond memories. This was my house (well, my parent’s house) in 1980. Back then my callsign was “HC1DT.” I had a TH3 on top of a tall tower, a 10m 3-element beam, and a bunch of home-made 2m verticals and beams.
As I had mentioned in the reflector discussion, my municipal permit allows my dish antenna to be up to 15 ft in diameter, so a project that will possibly precede the erection of the two towers is to expand the diameter of my EME dish from 12 ft to 15 ft. I’ve been looking at how other hams have done it, and I think that the following are the best examples of what I would like to do:
This increase in diameter should have a theoretical gain change from 11.3dB to 13.6 dB at 1296 MHz.
I would be interested in knowing any experiences by other hams who have modified their dishes for larger D. Anyone tried doing it to a Tek2000 dish?
I have received approval from the XYL for expanding my antenna garden, so I’m planning the projects for the upcoming fall and spring. NJ law allows me to put up a 70 ft tall tower (excluding the antenna) without interference from the township, so I’m planning to take it all the way to that height.
The tower next to the house can be supported against the outer wall of the house, and I’m intending to place a 6-element HF beam and a a large 2m/70cm EME array on top of that tower. My limitation is a 16 ft boom so that I can keep within 15 ft of my property line. That’s certainly enough for a large, high-gain array.
The second project is to elevate the current 12 ft microwave dish to expand my horizon. This will need a very heavy-duty, self-standing tower because of the wind load presented by the dish. I need to take some measurements and see what would be the best compromise between height and achieved minimum inclination, but I feel that will fall somewhere around the 30 ft range.
I’m currently looking at the specs of ROHN towers, and would love to hear feedback from current users under similar load conditions.
PS. Finishing the power amplifiers for 1296MHz EME right now… see you soon on the Moon at 23cm!
I am now concentrating the bulk of my ham activities in the microwave region, and have CW EME and amateur DSN as my top projects. My goal was thus to install a relatively large prime-focus dish to be moved by a heavy-duty Az/El rotator.
In this whitepaper I describe how I modified a Tek2000.com 12 ft TVRO mesh dish so that it can be moved by a SPID BIG-RAS Az/El rotator.
Location of whitepaper: Tek2000 antenna on AzEl – N2QG
It’s July 20, 2019, and I am invited to a private screening of the CNN Apollo 11 documentary, followed by a party with my fellow nerds, so I don’t really have time today to work the sats. It’s 102ºF outside, so not a good day to tweak the antennas either, but I nevertheless wanted to do something space-related to celebrate the 50th anniversary of the Apollo 11 Moon landing.
As a compromise, I decided to test a Trivec-Avant AV2040-2 SATCOM antenna indoors to see if it would be suitable as a portable antenna in the VHF and UHF ham bands.
I was cleaning my desk today, and came across a folder containing correspondence about a legal threat that I received a few years ago from someone accusing me of copyright infringement.
The accusation was that I had used his published data in one of the figures in one of my books without his permission, and had thus violated his copyright.
For my figure, I had drawn a stylized graph which matched the data presented in his graph, but I didn’t copy his figure. He acknowledged the fact that I had “changed the colors and style,” but insisted that the fact that he had placed a copyright notice meant that the data were his, and that anyone publishing a graph that matched these data would be infringing on his copyright.
Although presenting and contrasting previously published data are the basis for academic discussion, which is why it didn’t even cross my mind that I would be doing something unethical or illegal by presenting my version of the graph, I wanted to make sure. Indeed, I was right – in the US, as in most parts of the world, ideas, procedures, and data that can be independently retrieved or replicated (i.e. which are not specific to the subjective viewpoint of their creators) are not subject to copyright.
I also checked with the European Copyright Code, which states that the following are not to be regarded as “expressions within the field of literature, art, or science” that can be protected by copyright:
Furthermore, hearings regarding the US Database and Collections of Information Misappropriation Act of 2003 show that data are not protected under copyright. It is clearly stated that while certain databases may qualify for copyright protection if they exhibit some modicum of creativity in the selection, arrangement, or coordination of the data, in no case are the data themselves copyrightable.
Bobby Glushko, now the Head of the University of Toronto Scholarly Communications and Copyright Office wrote a very nice article about this very question while the Copyright Program Manager at the University of Michigan. The article is available online at:
Based on the explanations in the article, even if I had taken each single point of data in his chart, and just because it took him effort to acquire these data, it doesn’t mean that the data are subject to copyright protection. This is because:
“Facts, data, and the representations of those facts and data are excellent examples of things that require much “sweat of the brow” to create, but yet still do not receive copyright protection.”
Please note that I’m not a lawyer, so don’t take any of the above as legal advise. However, I hope this will be a good starting point for anyone who is threatened by a bully with a false claim of misappropriation of intellectual property based on use of published data.
CLICK HERE for a detailed writeup with high-resolution pictures in .pdf format.
The GOES-East (GOES-16) satellite (GOES=Geostationary Operational Environmental Satellite) operated by NASA and the National Oceanic and Atmospheric Administration (NOAA) is exactly due south of my QTH and provides a view of Earth centered right at my longitude (75°W).
GOES-16 transmits two interesting direct services:
I wanted to experiment with receiving these services from the GOES 16 satellite, and to do so, I added a small grid parabolic antenna to the Az/El boom that drives my 12’ EME dish. I purchased this antenna on eBay®. It is an Altelix WiFi 24dBi 2.4GHz parabolic dish with N-male connector that sells for $30:
This is the latest addition to my antenna farm. It’s a 12 ft mesh parabolic antenna on a heavy-duty AZ/EL rotator. My intention is to use it for 23cm and 3 cm EME, amateur DSN, as well as for next-generation amateur satellites/CubeSats and (hopefully) planetary probes.
Fortunately, my wife doesn’t mind my weird hobbies, my deed doesn’t have HOA restrictions regarding antennas, and New Jersey has a specific law that prohibits municipalities from adopting zoning ordinances that prohibit construction or use of antenna structures by federally licensed amateur radio operators (Act from Assembly No. 3641 of the State of New Jersey, 211th Legislature, introduced January 10, 2005)!
Thanks to the nice people at the municipal office, I was able to get a zoning/construction permit from my township with no issue. The construction inspector already gave me approval on the footing, so now it’s time to load a feedhorn and start to QSO off the Moon. The antenna is smaller than the maximum I requested in my permit, so I can still grow it by another ~3 ft in case I feel the need for a few more dBs.
Of course, I’m already thinking about my next antenna project. My thought is a tall tower to support a very large 2m/70cm EME array along with a 6-element HF beam. According to NJ Act 3641 I can put up a 70ft tower, and then place the antennas on top of that:
“No governing body shall adopt a zoning ordinance that prohibits or has the effect of prohibiting the construction, maintenance or use of an antenna and support structure therefor by a federally licensed amateur radio operator. Zoning ordinances may reasonably regulate the location and height of those antenna structures for the purposes of health, safety or aesthetics; provided, however, that those ordinances permit sufficient height of those antennas and support structures so as to reasonably accommodate amateur radio communications by federally licensed amateur radio operators.
Restrictions imposed on such antennas and support structures by ordinances shall constitute the minimum practicable regulation necessary to accomplish the legitimate purposes of the governing body enacting that ordinance. For purposes of this section, it is presumed that any ordinance that prohibits or has the effect of prohibiting any antenna support structure that is 70 feet or less in height above ground level, exclusive of any antenna upon the structure, is unreasonable. No federally licensed amateur radio operator, applying for permission to install or modify an amateur radio antenna or amateur radio antenna structure, shall be required to pay an application fee that is in excess of that which may be assessed for residential variances generally, nor shall such applicant be assessed any amounts for legal, technical, or other consultation or advisory costs incurred by the reviewing agency in evaluating the application submitted.”
I love my wife and I love NJ!
Jason Meyers (KC2TDS) and I (N2QG) had a fun weekend receiving SSTV from the ISS. We tested many different radio/antenna configurations. Along the way, we once again found out that Amazon “China-Special” connectors are worthless. I’m trashing any connectors in my adapter box that are not real AMPs!
The real interesting finding from this weekend’s campaign was that the SDR-RTL (fancy version) does slightly better for this application than an AOR AR5000, ICOM IC-R7000, and Yaesu FT-736R! We also tried the FunCube+ Pro against the SDR-RTL against weak terrestrial signals, and saw just a tiny bit extra SNR (the FunCube+ Pro has dedicated SAW filters).
Antennas used: 2MCP8A and log-periodic on Yaesu 5500 rotator, and eggbeater with Mirage preamp.
I’m currently rebuilding and expanding my space communication antennas with the intention of being QRV on 23cm EME, as well as being able to receive deep-space probes on the DSN X-band this coming spring. My favorite way of calibrating the Az/El rotors is to use FTA geostationary satellites, and as a reference, I upgraded my C and Ku-band small-dish (120cm offset) with a heavy-duty horizon-to-horizon (HH, H2H) motor.
I found that my ZGemma H7 FTA receiver could not handle the current needed to operate the motor, so I built a simple power inserter just for the motor. The 1uF non-polar capacitor provides a low-impedance path for the 22kHz DiSEqC signal to the motor, while at the same time the 10uH inductor isolates the RF from the LNB from entering the motor supply. The 500uH inductor (rated for 4A DC minimum) isolates the 22kHz signal from being dampened by the filters in the power supply (an old IBM laptop power supply rated 16V @ 4.5A).
Clean schematic in pdf: H2H Motor Power Inserter
Construction technique and enclosure are not critical, but the connection between the LNB and RECEIVER ports must be kept short. My housing is the enclosure of an old DISH Network switch that I emptied out and modified to add a power connector compatible with my power supply.
This works like a charm! The H2H motor now moves quickly and smoothly without shutting down the ZGemma’s tuners.
This is the current state of the Az/El VHF/UHF array and FTA dish at N2QG:
