Broadcast engineer and frequent tipster Dan Slentz was frustrated by the lack of a standard when it comes to 3.5 mm microphone plugs. So he put together the cheat sheet shown on this page. Print or copy it out and keep it handy, or take a picture and keep it on your phone. You never know “which” standard you will encounter.
And if you have “reminder images” of your own that are helpful in your work, share them with me at [email protected].
Emergency STL
I told you about consulting engineer Frank Hertel’s purchase of a reasonably priced portable DVD writer that supports M-DISC, a version of DVD used for archiving files. Archived files are expected to last 1,000 years.
Well, Frank has another gem. He found this one on AliExpress. It’s a $56 VHF/UHF receiver that covers 25–999 MHz.
This could come in handy for contract engineers. With its external antenna jack and audio output jack, in a pinch it would substitute for an STL receiver.
Now, it has a maximum bandwidth of about 5 kHz, but if you turn the STL transmitter modulation down to 10 kHz deviation (instead of the normal 50 kHz) the audio output is quite good.
Keep in mind that this is mono. But in an emergency, at least the station is on the air.
The unit can run on its internal battery or a 5 volt wall wart. Go to the AliExpress site and search for the HanRongDa HRD-757 Multiband Radio.
Frank also shares a useful IP address lookup/location finder he found online. You type in the IP address to obtain real-time information associated with that IP address, including country, city, ISP and geographic coordinates.
The site is one of many tools provided by the Web, Network and Security Toolbox published by Intech DC.
Breadboarding virtually
Frequent tipster Paul Sagi has designed a lot of circuits in the course of his career. He shares an online, in-browser toolbox for schematic capture and circuit simulation. The Circuit Lab site permits design and testing of analog and digital circuits prior to building a prototype. Set up your account at the Circuit Lab website.
Speaking of tools
The multi-tool gets some competition with this heavy-duty, multifunctional set of pliers sold by Mavigadget.
What caught my attention were the pictures of the tool cutting through chain links and lock hasps — even a screwdriver blade. You can also strip wires and adjust its wire-stripping blade.
The pliers are constructed using chrome vanadium alloy steel, and the symmetrical clamp head and teeth provide a firm grip. There’s also a crimping groove to crimp electrical connectors efficiently. The pliers cost less than $50.
Transmitter site checks
From time to time, I like to include small maintenance items to perform during your next check of a transmitter site. These aren’t major jobs but tasks that should be done regularly.
Start with checking the mouse traps. Then open up all the circuit-breaker panel doors and ensure that no breakers have tripped. Do you have a generator? Open it to check belts and fluids, especially the coolant level. The battery should be changed every 3 to 5 years. Place a label on the new one to help keep track (particularly helpful when you manage multiple sites).
Also check the tower base grounding. And look up the tower to spot anything waving in the wind. No loose cables? Then look down as you walk around the site. Any bolts or fittings that have fallen off?
Wrap up your cursory inspection by checking your air conditioners including filters and belts.
What items do you always check during your site visits?
Workbench submissions are encouraged and qualify for SBE recertification credit. Email [email protected].
