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  1. Receiving the HamSci WWV Scientific Test Signal

    I was perusing the latest edition of QST and noticed a short article on some scientific experiments that hams were doing with WWV and WWVH. I tune in to WWV occasionally to check propogation, and also for frequency calibration of my Kenwood TS-2000.

    April 2022 QST article on WWV science

    Wow, this seems cool! The HamSCI WWV webpage has a bunch of information, including a great presentation by Kristina Collins KD8OXT.

    Receiving the Signal

    I recently added a KiwiSDR at my home station, so I twisted the dial over to WWV (in software, pretty anticlimactic), and started listening. I barely heard the test signal from Hawaii because propagation that evening was very poor. There was several solar flares over the next few days, causing lots of interference ...

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  2. Simultaneous Multi-Band WSPR Decoding with KiwiSDR and WsprDaemon

    I've been interested in receiving Weak Signal Propagation Reporting (WSPR) signals recently, for two reasons. The first is that the picoballoons that we launch use WSPR for position information. Not only do I directly receive the picoballoons after we launch them, but I also use the WSPR network to check on their location around the world. I don't have a receiver in Europe, so I rely on other amateur radio operators to receive the balloon and post its location online, and I want to give back to the network.

    The second reason is that I'm curious about how far I can receive signals with my somewhat compromised city antenna. While my fan/parallel dipole antenna will never perform as well ...

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  3. Building a Multi-band Fan/Parallel Dipole Antenna

    Now that Solar Cycle 25 is upon us, I wanted to get active on the HF bands. My primary bands of interest are 40 and 20 meters, so I wanted to build a multi-band antenna for these frequencies. After some research, and wanting only one antenna connection for my Kenwood TS-2000 radio, I settled on a fan/parallel dipole antenna. It's very simple to build, and really hard to beat the performance of resonant dipoles.

    Choke Balun

    A balun is required when you are interfacing a BALanced device, such as a dipole antenna, to an UNbalanced device, such as a coaxial cable. Coaxial cables are unbalanced because from an RF perspective, there are actually 3 conductors in a ...

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  4. Building a Quarter-Wave Ground Plane Antenna

    After my talk at Pacificon a few months ago, several people reached out to me about setting up a radiosonde receiving station at their house. They specifically had questions about the antenna and LNA, and after answering the same question a few times I decided to do a post about this topic.

    Building a 1/4 wave ground plane antenna is very easy to do. The overall design is simple, with a vertical element surrounded by a ground plane consisting of two or four wires bent down. Here are the dimensions for the VHF/UHF amateur radio bands (from the ARRL Handbook), but these dimensions can be scaled to any frequency.

    Quarter wave vertical antenna construction diagram

    There are many online calculators that will give you ...

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  5. Pacificon 2021 Picoballoon and Radiosonde Presentation

    David WB6TOU, Martin W6MRR, and myself gave a presentation at the Pacificon, which is the annual ARRL Pacific Division ham radio conference held in San Ramon in the fall. Our presentation was titled "Picoballooning in the Bay Area: High Altitude Balloons, Picoballoons, and Radiosondes." Download the slides here.

    We also used this opportunity to launch the new SF-HAB website, which is a collection of how-tos, resources, and blog posts about our ballooning activities.

    The first third of the presentation was David talking about balloon mechanics, including how to prestrech, fill, measure, and release SBS-13 and cheap Aliexpress picoballoons. David launched two SBS-13 picoballoons from the Central Valley in winter 2021, one of which went 2.5 times around the world ...

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  6. Kenwood TS-2000 Frequency Calibration

    I've been spending a lot of time recently listening to WSPR beacons. The recent picoballoons that I have launched all used WSPR for to transmit their location and altitude. WSPR is a great for solar-powered picoballoons because the transmit power is on the order of 10 dBm (10 milliwatts), which is extremely low.

    One night, I was just passively watching the WSPR decodes while doing other things on my shack computer. Every once in a while, I would notice a WSPR beacon that was outside of the 200 Hz WSPR band, and therefore wasn't decoded by WSJT-X. I thought this was interesting, who was transmitting out of the band? The transmissions seemed to always be on the high side.

    This ...

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  7. W6PW SOTA Activation of Mt. Davidson, W6/NC-423

    After my very successful SOTA activation of San Pedro Mountain the previous weekend, and the San Francisco Radio Club Angel Island expedition at the same time, the club decided to do another SOTA activation on Saturday November 14th. Antonis AA6PP, Jeff KK6JJZ, Rick K6TOR, David KN6HFV, and myself went up to the top of Mt. Davidson and activated the peak under the club's callsign W6PW.

    It was a beautiful day, very clear after the rains the previous evening. We had a total of five stations. Antonis AA6PP and Jeff KK6JJZ ran the HF voice stations, trading off on 40, 20, and 15 meters during our activation. Rick K6TOR ran HF CW, and Dave KN6HFV ran the UHF station on 445 ...

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  8. SOTA Activation of San Pedro Mountain, W6/NC-410

    Summits on the Air (SOTA) combines two of my favorite pastimes, amateur radio and hiking. The objective is to climb to a nearby peak, then contact as many people as you can on the radio. While most SOTA peak activations are on HF, my only portable gear at the moment is a few HTs.

    On Saturday Nov 7th, I activated San Pedro Mountain, which is 1058 ft tall. It's located in Harry A. Barbier Memorial Park in the hills above San Rafael, next to China Camp State Park.

    I took the Knight Dr route, from Tom AI6CU, hiking along the Ridge Fire Road. The hike up took about 45 minutes, and some sections of the trail were very steep. I ...

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