KPBS-FM 89.5 in San Diego can now fire up its legacy site on Mt. San Miguel in the event of some failure or maintenance needs at Mt. Soledad. The FCC issued the license this week. You might remember that the San Diego State University NPR affiliate moved to La Jolla last year, increasing power and overall increasing service to its strong donor base to the north and west. It only made sense to maintain the equipment at Miguel for backup purposes since the TV transmitter remains there anyway, and that’s what they’ve done.
All posts by Gary Stigall
Stubs for Fun and Profit
A year ago I was helping out temporarily at Bext with technical service and a number of interesting challenges came up. One was from a customer whose low power FM transmitter shared a site with a mobile carrier. The carrier’s technician was complaining about the transmitter’s 8th harmonic getting into his radios. The FM transmitter in question was clean far beyond FCC requirements of -80dB below assigned carrier level (as I remember, about -96dB) but on a spectrum analyzer, you could see a tiny bump down near the noise floor in the 800 MHz band. I used the analyzer and its tracking generator to trim a hunk of coax and knock down the 8th harmonic of the offending FM transmitter about 20 dB. That’s a pretty short piece of coax, by the way. Problem solved and nobody had to build a Faraday cage.
A June article in the BDR mentions this conflict between the very sensitive LTE mobile site receive inputs and their FM transmitter neighbors. These radios are attempting to discriminate data at -120 dBm and lower from distant tiny transmitters inside metal cars and buildings.
I first ran into an application for a stub with a TV translator site in the Oregon high desert in the early 80’s, where I was receiving a faint UHF signal beyond line-of-sight and picking up some birdy from my channel 5 output. With an N-connector “T” adapter and a quarter-wave length of RG-213, I fashioned an open-ended stub that resonated at the mixer product, attenuating it enough to remove the problem from the visual band of my UHF input.
Another recent article in Radio World magazine, this by Mark Persons, suggests putting a bandpass filter in the form of a quarter-wave shorted (not open) stub after a solid-state amplifier feeding a tube amplifier. This is brilliant. It serves to attenuate voltage spikes that might enter since only the resonant frequency passes without great loss–DC and pulses slow and fast are shorted out. By the way, this won’t work with TV or other broadband applications due to the high-Q of the stub.
Check out articles on construction of these stubs online.
Making Waves: Our Summer Jobs
(Commentary) For better or worse, I share much of my DNA with my father, Herb, who has throughout his 84-year life so far, insisted mostly on doing everything himself. The story I often tell to illustrate this point is about when we lived on a 40-acre ranch in Central Oregon requiring constant fence and pasture upkeep during the hours he wasn’t driving an oil truck full-time. He found termites in the bathroom of the old homestead and learned that they came from a path of dirt and wood from the ground. This wouldn’t do. So he reconstructed the substantial foundation, lifting the house with jacks and spooning mortar in the small spaces between lava rocks that he had dragged under the house one at a time. I know because I helped mix the mortar and pushed rocks through the vent openings to him.
You can run a broadcast engineering business like this, doing it all yourself. You can run cables and terminate them, install and configure equipment, assemble satellite dish kits and climb towers. It’s mostly intellectually engaging, you accumulate experience and leave each project with a pride of ownership.
It will also drain you because you can never keep up with all the work, you can’t take time off really, and you will limit your income potential greatly. This is because you can’t charge enough for the installation work to cover all the overhead you don’t get paid for, like accounting, marketing, and purchasing.
This is one of the basic tenets of small business. Basically, if you are doing the busy work, you’re doing it wrong. A small business owner should be tending to strategic planning and business development, leveraging income by hiring good help to handle the day-to-day activities that make up the foundation of your technical service business.
Employee #1
As much as it goes against my instinct, I decided that when young students were between college terms earlier this month, it would be a good time to hire. I listed in Craigslist an opening for a broadcast engineering “apprentice.” I didn’t want to say “intern” because this is a real job and a paid position and in California the term intern has legal limitations when you are not paying (even though most employers seem to ignore the rules at their own peril). I believe that students or those looking todevelop careers deserve to be paid for their work, whether they are bringing real talents to the job or just working hard. In my opinion, there’s entirely too much slavery going on, and it’s hurting our economy by cutting off the income of people who should be out there consuming.
Within a few minutes of posting the opening, I got a resume and cover message from Julio Ramirez, a young man who seemed to fit my three needs: (1) self-initiated computer hobbyist who had dabbled in programming and/or networking, (2) a customer service attitude of respect and friendliness, and (3) long-term interest in broadcasting or something like it. I hired him the next day even though responses were still piling in. Some resumes were short on something, some were vastly overqualified and might suit a future full-time opening (or they should work independently!), but this one was just right.
So Julio and I have had our first week together, running and punching in UTP cables with another helper one day, finishing for me a complex batch file for a CALM Act audio monitoring program another day, and assisting with a commercial cueing problem I had been dealing with. Once a graphics student, he even had a logo designed for my badly ignored website before we could even get started. He’s learning new skills faster than a classroom lecture would give, and I’m clearing my TO DO list with rapid relief.
If you have some work to do that you’ve had to sideline while you grapple with your day-to-day, consider hiring someone from that huge pool of underemployed technicians out there. While you aren’t likely to find someone you can send to the transmitter for a quick fix, most broadcast work these days involves microprocessors and the kind of technical problems you can solve with Google searches, a technical mind, and time.
I took the big step to employer, and we’re going to have a terrific summer.
June Member News – Welcome Chuk Gawlik
Charles Gawlik of San Diego passed his Certified Broadcast Network Technologist (CBNT) exam at the NAB Show in Las Vegas in April and has become a member of Chapter 36. He’s a systems engineer for Vigor Systems in La Jolla by day and a photographer by night. Congratulations Chuk!
KNSJ Getting Ready for Air
According to their website, new non-comm KNSJ installed their antenna at Monument Peak and expect to hit the air on 89.1 MHz as soon as they install their transmitter. The FCC lists the station as having an ERP of 330 watts and city of license as Descanso, but the elevation will give the station a decent signal to line-of-sight locations throughout San Diego County. The organization behind the new station says in their mission statement:
Activist San Diego is a social justice organization that promotes and facilitates the development of an active, inter-related, progressive community in San Diego through networking, culture and electronic technology.
For the time being, listeners in the Pacific Beach, La Jolla, and University City areas shouldn’t expect much reception due to co-channel 4-watt K206AC in La Jolla that rebroadcasts KPBS-FM.