Author Archives: k0dvb

Another year, another antenna

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Actually, this year it’s an antenna farm in the attic. After moving out of Boulder this summer from a townhouse to a free-standing house, I needed a new antenna setup.

I now have a pair of X50 antennas (one east, one west) for VHF/UHF along with a west-facing M2 UHF yagi for TV (the 440-6SS, 6 elements and about 36″ long). I used an upside-down dish mount arm to hang it up.

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I can receive the WØBCR TV repeater in Chautauqua Park at -62 dBm with a very clean signal (at a distance of 16 miles), better than the direct reception I had when I was located in Boulder.

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Until someone builds a house behind me, I have line of sight to Chautauqua as well as to NCAR (for the BARC voice repeater and the KCØDS D-star repeater).

For the X50 antennas, I pre-made a mount that I took into the attic in one piece:

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which I then nailed down to the rafters:

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I also installed an HF loop using an SGC-237 autocoupler, but I haven’t got it working yet.

BARCFest 2016

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I demonstrated the digital quad box for BARCFest attendees and attracted lots of interest. I had two TV backpack transmitters of my own placed in corners of the building, plus a signal from Jim KH6HTV showing home video, plus a video input from a stationary drone camera belonging to Allen KØARK (the receiver is the white device on the far left of the table; it is connected directly into the HDMI switch).

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On the right I have a laptop receiving the video stream over an Ethernet network, using a Monarch HD streaming appliance (the silver part in the middle of the quad box).

The embedded HDMI switch makes it easy to substitute video sources into the quad processor as well as choose which images are shown on monitors or fed into the streaming device.

TV support for public safety exercises

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This past week I deployed a new quad DATV receiver box in support of public safety exercises.

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Built around an 8×8 HDMI matrix, the box can substitute other video sources as inputs to the quad processor; below, we have two TV channels and the output from a drone camera on the monitor.

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The switch also allows output of both quad and simplex pictures to any of several monitors or a laptop or other streaming appliance. During this exercise we experimented with streaming the quad box’s output over a private local wireless network.

Note that I’ve moved to using HV-120 receivers from Hi-Des; these are powered by 12v instead of 5v, have channel ID and manual channel up/down buttons on the front, and have a new, much improved remote control.

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Thanks to Mark KØLRS who worked with me on the video setup.

BCARES from the Dalai Lama to Dead & Co.

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BCARES again provided digital ATV support for special events at the University of Colorado, including the make-up visit of the Dalai Lama 6/23 and two evening concerts by the Dead & Co. during the Independence Day weekend.

BCARES camera crews provided real-time situational awareness for medical and law-enforcement issues as well as crowd and traffic control before, during, and after these events.

BCARES digital ATV support for the GOP debate

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Yesterday a team of eleven BCARES members provided nearly eleven hours of digital ATV coverage at the GOP debate in Boulder, assisting the University of Colorado PD and the Colorado State Patrol who ran security for the event. In addition, we provided video to the Boulder County EOC for about six hours with the help of two more members who staffed our cube there. Here one of our cameras operates near the VIP entrance.

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For this event we extended our reach across campus to a much greater degree than ever before. Pretty much all the coverage areas did not have a strict line of sight back to the stadium; instead, we depend on reflections off the stone faces of campus buildings to help get the signal to the receiving antennas.

We used the same TV antennas at the football stadium that we’ve used for actual football games. Here our quad box is showing the two early cameras; we went to four cameras later in the day. The quad output was streamed over IP through the campus network to the command post, providing a view of protesters as well as VIP arrivals and departures.

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By increasing the DVB-T forward error correction (FEC) coding rate to 1/2 or 2/3 we were able to maintain a low power level (300 mwatts) in most locations even in the face of interference from commercial TV production trucks with their powerful satellite uplinks. For some locations close up against buildings, we need to raise the level to 1-2 watts to maintain a good signal.

We used the BCARES portable VHF voice repeater for the first time, installing it on one of the tallest buildings where it can cover the entire campus. Here Mark KØLRS finishes programming it before the event.

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Many thanks for the hard work of Mark KØLRS, Dave KIØHG, George NØRUX, Doshia KBØNAS, Mark NØXRX, Ron KCØNEV, Tom KDØUI, Ron K2RAS, Bill KDØYYY, Steve WBØNFQ, Steve KS3FOX, Jerry NØOUW, and Joe KCØJCC!

My birthday present

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I managed to convince my homeowner’s association to allow me put an antenna on the roof, so I assembled it today (which just happens to be my birthday). I also have one on the third-floor balcony. Maybe I can call it a work of modern art!

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Since the rooftop is flat, and I don’t want the future expense of a damaged roof, I used a Rohn FRM166 non-penetrating mount.

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With the concrete blocks as ballast, the mount (like the X-50 antenna) should be good for winds up to 130 mph — faster than what’s been recorded in or around Boulder.

The antenna is about 30 feet up on a townhouse which sits at about 5630 feet above sea level. Unfortunately, given the hills behind my house, my HAAT turned out to be negative. The antenna does have a great view north, east, and south, though.

BARCfest 2015

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I spent this Sunday morning at the BCARES table showing off digital ATV transmitting from a backpack set. Live TV made a good draw to our table in the back of the room. Lots of folks came over to ask about BCARES as well as ATV and the equipment on display. I also had the DVB-T portable repeater as a static display (i.e., it wasn’t running).

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I made a couple of tours around the swap meet recording as well as transmitting.

BCARES digital ATV in support of CU football

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This Saturday 9/12 I and six other members of BCARES ran digital ATV cameras at this year’s first home football game at the University of Colorado. This marks our first all-digital ATV operation providing TV for situational awareness to the CU police department.

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This operation was also our first use of the new HDMI-based quad box, allowing up to four digital ATV channels to be combined in high definition. The resulting output was streamed over an IP network from the press box to the command post located away from the stadium.

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While the stadium has fixed cameras, our mobile cameras allow the CU security team to focus on areas around the stadium that are not well-covered as well as to get close-ups of incidents as they happen, particularly on the move. For BCARES, supporting CU football offers us a great training opportunity as well as a safe environment to prove out new technology.

The DVB-T transmitters were able to work with and without line-of-site to the antenna location on top of the press box using only 300 mW while sending a perfect 720p picture at nearly 6 Mbps.

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Thanks to Mark KØLRS, Dave KIØHG, George KAØBSA, Pete WB2DVS, Tom KDØUOI, and Bill KDØYYY for all their hard work!

Digital ham TV (ATV) training for BCARES

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This past Saturday 8/29 I hosted an all-morning training session for BCARES members who are interested in digital ATV operations. The turnout was very good!

The first part of the training covered TV operations and the use of the video cameras and digital transmitters, particularly using ATV at CU football games. This part is comparable to the analog ATV training in prior years, but with changes brought about by the switch to digital.

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In the second part, I covered some technical aspects of the European DVB-T system we use, specifically the transmission parameters we can set and how we decide what values to use to ensure we can get a picture through with low RF power and a noisy environment.

In addition to a static display including digital backpack transmitters and a portable repeater, I had live video running in the classroom, with pictures on a TV and signals displayed in a DVB-T test tool.

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Thanks to all who showed up, and to Dave KIØHG and Mark KØLRS for bringing the new digital quad box and CU pack sets to display.

Handouts from the training are available in the ATV training section.