Justin K5EM
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k5em.com
Justin K5EM
@k5em.com
360 followers 270 following 80 posts
Tech, ham radio, hacking, weather. Enjoy SDR, antennas, contesting, satcom. HW/FW/SW engineer mapping with drones. He/him. http://satmatch.com also @[email protected]
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k5em.com
Fun morning knocking out a Pasadena area favorite SOTA summit with John before the last day of SuperCon
Two men are smiling outdoors on a sunny day with mountains in the background. The man on the left has gray hair and a short beard, wearing a colorful patterned shirt. The man on the right is wearing a gray hoodie and a dark baseball cap with a round multicolor patch. They’re standing on a dirt trail overlooking a wide valley filled with trees and a distant city, with tall, rugged mountains rising behind them under a clear blue sky. A foggy morning view from the hills, looking out over a valley blanketed in thick fog. Only the tops of tall buildings rise above the fog in the distance, surrounded by soft blue-gray layers of hills. In the foreground, a few palm trees and green shrubs stand out against the haze, creating a peaceful, dreamlike scene.
November 5, 2025 at 4:35 AM
k5em.com
Got it! Walk up to them, give them a pet, check their teeth and tail, then whack them over the head. We grew up with these "river rats" water skiing on the Brazos. They could be surprisingly aggressive if you happened to fall too near their nests. They'd even jump into the water and swim after you.
March 31, 2025 at 5:09 PM
k5em.com
10 barely showed for us at KZ1W. A few loud EU stations our Sun morning, enough to pick off some extra mults, but never enough to get a run going. 15 and 40 were overcrowded. We had the benefit of a good supply of JAs on 15 for a few hours after each sunset. 20 was noisy, had to point JA to hear EU.
KZ1W claimed score chart for CQWW WPX contest. Shows the most points on 21, 7, and 28 MHz. Overall 2463 QSOS for 6049 QSO points and 977 Prefixes for a claimed score of 5,909,873.
March 31, 2025 at 4:53 PM
k5em.com
Don't get a Rivian then... My BLE scoopers pick them up constantly on my Home Assistant install as they drive by. Presumably they roll something as I can't imagine over 100 Rivian have driven by.
March 28, 2025 at 7:57 PM
k5em.com
My current setup is just some Amcrest 8k cameras for wide views and one raspi HQ with a nice Edmunds telephoto lens on the hummingbird feeder (through a window). Everything feeds to the NAS for event tagging.
March 23, 2025 at 6:29 PM
k5em.com
A little sun, snow, and family therapy today. Beautiful day to be in the mountains.
January 20, 2025 at 6:55 PM
k5em.com
Great visual and #hamradio #ISS pass for Seattle too starting in the Southwest at 6:17PM and going right overhead. #wawx
January 18, 2025 at 12:06 AM
k5em.com
Last day to order a SotaCAT for the year! Get WiFi control, click-to-tune spotting, and SotaMAT integration on your KX2/KX3. We have a few in stock still; any in-stock orders today will ship tomorrow, then we're taking the holidays off.
store.invertedlabs.com
December 19, 2024 at 7:55 PM
k5em.com
The other one I hear from my station here a lot is KL2T. 12m might be a little hard this time of year but should be easy next summer. Best chance is probably a very late opening on your side on a hot sunspot day. Graph is for December from Clublog; January is much worse and February is improving.
Graph of QSOs between England and Alaska in Clublog for the month of December, showing peak around 1000-1100 UTC and 1600-1700 UTC
December 13, 2024 at 5:17 PM
k5em.com
🎶 Christmas time is here 🎶 c/o gpt:

Receivers strain to hear
But noise is oh so near
Glowing reindeer on the lawn
Make pure reception disappear

I tune and adjust my knobs
To find that perfect tone
Yet flick’ring bulbs and singing shrubs
Turn clear bands into drone

Oh, static noise is here...
Screenshot of my websdr receiver here in Seattle showing 0-30MHz with a ton of radio noise across the whole spectrum, presumably from local christmas decorations.
December 11, 2024 at 6:04 PM
k5em.com
SotaCAT is a small hardware module that plugs directly into a KX2 or KX3 radio to allow radio control from any WiFi connected device. SotaCAT serves up a web page that, by sharing your data conx, can show real-time SOTA and POTA spots so you can "click to tune" directly to the spot freq and mode.
December 11, 2024 at 1:42 AM
k5em.com
For the past year or so, I've been working with @ab6d.bsky.social to turn his SotaCAT design and concept into a ready-to-buy hardware design. After a couple of pre-order rounds and testing, today I opened the web store for general SotaCAT consumption. So what is SotaCAT exactly?
SotaCAT, a small orange elongated cube, is plugged into the side panel of an Elecraft KX3 amateur radio transceiver.
December 11, 2024 at 1:42 AM
k5em.com
Beautiful start to the morning in Western Washington #wawx
This picture captures the stunning view of Mount Rainier and Lake Washington during sunrise. The lake in the foreground is calm, with soft ripples reflecting the warm light of the sky. The shoreline beyond the water is lined with dense, dark trees, partially obscured by a thin layer of mist rising in the early or late hours of the day. Mount Rainier stands majestically in the distance, its snow-covered peak glowing faintly against the warm tones of the sky. The sky itself is a breathtaking palette of orange, pink, and red, with streaky clouds stretching across it, creating a sense of depth and tranquility. The overall mood is serene and awe-inspiring, highlighting the beauty of the natural landscape.
December 5, 2024 at 4:24 PM
k5em.com
Finally managed to find some time to put a bunch of stickers I've been collecting on the laptop!
This image shows the lid of a laptop covered with various stickers. The laptop appears to be a ThinkPad, as indicated by the subtle logo in the top left corner. The stickers include: "NOT FOR MISSILE USE" – A humorous sticker in orange text on a gray background, located near the top center. Cascadia Radio – A colorful circular sticker on the left with a rainbow, a tree, and a mountain. The text reads "CascadiaRadio.org" with "Pacific Northwest Amateur Radio for All" below. Safety Third – A red circular sticker with a white cross and flames, located near the bottom left. 4O3A Station Automation – A rectangular sticker in black with green waveforms and bold text in white. Join the Resistance – MightyOhm.com – A black sticker with white text in a pixelated font near the center. NASA KSC Spectrum – A hexagonal sticker with a color wheel and overlapping leaves, representing the Kennedy Space Center spectrum project. N7KOM On The Air – A sticker in the top-right corner reading "In the mountains" above and "N7KOM On The Air" below, with radio waves and mountain art. DX Engineering – A large rectangular sticker with the DX Engineering logo in red, black, and gray, also near the top. Wilderness Labs – A smaller sticker featuring a mountain outline, located at the bottom center. K6ARK Portable Radio – A black and white sticker in the bottom-right corner, depicting a radio with the label "K6ARK Portable Radio." Miscellaneous designs – There are a few smaller stickers and designs, such as one with stripes in the top-right corner. The laptop is placed on a colorful background resembling a space or cosmic theme, adding contrast to the sticker designs.
December 4, 2024 at 9:58 PM
k5em.com
Nice quick #hamradio Summits on the Air activation today before the bomb cyclone hits late this afternoon. #SOTA
I am outdoors in a forested area, sitting on the ground and smiling at the camera. I am wearing a puffy blue jacket and have some equipment in front of them, including a notebook and a small case with, with an Elecraft KX2 on my left knee. Next to me is a fluffy white and black dog is sitting, looking off into the distance. The background is lush with mossy trees, ferns, and fallen leaves, creating a peaceful, natural setting. The image shows a fluffy white and black dog sitting on the forest floor, looking at the camera with a curious expression. In the foreground, there is a close-up view of a small black electronic device, possibly a portable radio or communication device, held by someone whose knee is visible. The device has a digital display showing numbers and various dials and switches. The ground is covered with brown leaves, green moss, and ferns, adding to the forest setting.
November 19, 2024 at 9:01 PM
k5em.com
Thanks to the operators of the VK2GGC SDR for the ability to create some of the images above by listening in on the other side of the world. The rest were heard and screenshotted on my RX-888 SDR here in Seattle. vk2ggc2.ddns.net:8074
Spectrogram showing more blips and bloops. Spectrogram showing more blips and bloops, this time focused on the 10m amateur radio band and just below.
November 14, 2024 at 12:43 AM
k5em.com
So, back to hearing them in Palau. We can only guess that we were hearing the startup of manufacturing lines one ionospheric hop away in Indonesia or Vietnam. These are just guesses, as these signals reflect and refract off the ionosphere and could be coming from significant distances at times.
This image is a polar azimuthal map focusing on Southeast Asia and surrounding regions. It shows geographic areas like China, Japan, the Philippines, Indonesia, Thailand, Vietnam, and Australia, which are labeled and outlined in black. The map uses a blue color to represent the surrounding bodies of water, such as the South China Sea and the Pacific Ocean. Latitude and longitude lines are displayed around the curved edges of the map, with degree markers running from 240° to 310°. The map provides a detailed view of countries and major islands in this part of the world, centered on Southeast Asia.
November 14, 2024 at 12:43 AM
k5em.com
... but that clearly isn't always the case. Shielded rooms are expensive!
This image shows a row of large blue industrial machines labeled "HIPOWER PVC welding machine" arranged in a spacious and well-lit manufacturing facility. The machines are lined up in a neat, organized manner, each equipped with control panels and welding platforms. The setting has a clean, white interior with high ceilings and overhead lighting. The floor is smooth and gray, and the atmosphere suggests a modern production environment. The text "HIPOWER PVC welding machine" is overlaid in a yellow box at the bottom of the image.
November 14, 2024 at 12:43 AM
k5em.com
The timing leads to an industrial or commercial application. Sure enough, when I got home I started doing some research, and others had received these signals as well. They are likely 27MHz high frequency welding machines for vinyl and polyurethane. They should be operated in a shielded room...
This image depicts a person operating a large industrial machine labeled "HIPOWER HF PVC welding machine." The machine has a robust, rectangular design with various control buttons and a prominent welding area in the center. The person, wearing a dark shirt, is standing to the right of the machine, using their hands to position or adjust material on the welding platform. The surroundings suggest an industrial or manufacturing environment, with boxes and other equipment visible in the background. The text "HIPOWER HF PVC welding machine" is overlaid near the bottom center of the image.
November 14, 2024 at 12:43 AM
k5em.com
My first experience with them was during the T88WA DXPedition in Palau. The first clue was the timing. They would start at 8AM local time, and we would tend to hear them on 10m (28MHz). At 9AM local, more would appear. The cacophony they made sounded like a Star Wars lightsaber battle.
This image is the cover art for the video game "Star Wars: The Clone Wars - Lightsaber Duels" for the Nintendo Wii. It features animated characters from the Star Wars universe, including Obi-Wan Kenobi, Anakin Skywalker, Ahsoka Tano, Mace Windu, and General Grievous. They are depicted in dynamic poses, holding glowing lightsabers in various colors, such as green, blue, and purple. The background is filled with action and light effects, emphasizing the intensity of the lightsaber duels. The top of the cover displays the title "Star Wars: The Clone Wars" in bold yellow letters, with "Lightsaber Duels" written below. The Wii logo is shown in the upper right corner, and the LucasArts logo is in the lower right. This image shows a scenic landscape featuring large wire hexagonal beam antennas mounted on tall metal masts, situated on a grassy hilltop. The antennas have a complex, spider-web-like design and are pointed toward the ocean in the background. In the background, there are lush green trees stretching toward the horizon, with a view of a calm, expansive ocean. The sky is mostly clear and blue, with some soft, wispy clouds and a visible moon. A small building with a metal roof is seen on the left side of the image, blending into the natural setting. The scene captures a peaceful, coastal atmosphere.
November 14, 2024 at 12:43 AM
k5em.com
Are they ionosondes, or "sounders" that measure the height of the different layers of the ionosphere? Definitely not, as sounders tend to change frequency very linearly with time.
A spectrogram of an ionosonde, where showing a slanted line as the sonde changes frequency linearly with time, as well as many signals that make mostly vertical green and red lines on a blue background.
November 14, 2024 at 12:43 AM
k5em.com
Depending on where you are and the time of day, you may see or hear a whole lot of these or none at all. They may be super loud, right at the noise floor, or somewhere in-between. They may be there all the time or fade in and out. Some come and go in a second or two, others last 5 second or more.
This image is another spectrogram showing a frequency spectrum over a range of 26.75 MHz to 27.45 MHz, indicated along the top. The background is mostly dark blue, with vertical lines and patterns in bright blue, green, yellow, and red, representing the strength of signals at different frequencies. Stronger signals are shown in brighter colors, with red and yellow indicating particularly intense signals, and blue or green indicating weaker ones. The spectrogram illustrates the varying intensity of frequencies over time. In the background barely above the noise floor we can see a number of these fish hook shaped signals. In this image, a fish hook signal starts, rapidly shifts to another frequency, and then oscillates a bit for about 5 seconds before disappearing.
November 14, 2024 at 12:43 AM
k5em.com
Continuing discussing these funny shapes in my waterfall from the other site. Sometimes when looking at HF waterfalls, we see these funny blips that change frequency quickly and make shapes that looks like tilted "S"s or some have said fishhooks. What are they?
An image of a spectrogram, which is a visual representation of the spectrum of frequencies of a signal as it varies with time. The top part of the image shows a waveform or frequency spectrum in a green line graph, with frequency peaks marked. The bottom part of the image consists of a heat map in shades of blue, green, yellow, and red, representing the intensity of various frequencies over time. Brighter colors indicate stronger signals, while darker areas represent weaker signals or noise. Most of the signals in the waterfall are more or less straight lines, but some signals, mostly between 26.8 and 27.8 megahertz, change frequency rapidly with time. The imprints they make on the waterfall have been called "S"s or "Fish hooks" because of their shapes.
November 14, 2024 at 12:43 AM