Category: Soapbox

We Need a Better UHF Connector

~ radioartisan ~ 8 Comments

The venerable UHF connector was developed in the 1930’s.  It has withstood the test of time and for the most part is a good connector for HF and VHF applications in amateur radio.  It’s fairly inexpensive, has somewhat intuitive assembly, and is mechanically robust.  From an RF perspective it’s not bad at HF and VHF, but despite the UHF name it exhibits an impedance bump at UHF frequencies and is usually avoided for UHF applications.

The UHF connector suffers from two problems, in my opinion.  One is that it’s not weatherproof.  You absolutely, positively should not have a UHF connector outdoors without weatherproofing.  If you do not weatherproof it, you will have water intrusion into the connector and probably into the braid of the coaxial cable.  Weather. Proof. It.  Connectors like the N connector  (a very common connector in commercial RF applications) which sports rubber gaskets on the mating surface and within the body of the connector are weatherproof, although it’s still advisable to use weatherproofing with the N connector.

The second issue is the difficulty in soldering the braid.  The holes in the body of the UHF connector expose the ground braid and you’re supposed to solder through these holes to make a positive connection between the braid and the connector body, and provide mechanical strength and stability.  Some folks pre-tin the ground braid before inserting it into the body, others do not.  You need a high wattage iron to do this properly and the heat required can melt the dielectric in the process.  I think many people don’t solder this well and some avoid doing it at all.

K3LR demonstrated an alternative method of soldering the braid to the PL-259 in this video:

I’ve tried this technique and for the most part it works.  (I prefer to use heat-shrink tubing around the exposed soldered braid.)  However, as you can see from the video it’s not pretty as it requires increasing the diameter of the dielectric with electrical tape, and there is not a snug fit between the connector body and the soldered braid and the coax jacket.  This technique in my opinion does provide a better braid electrical connection than most mere mortals can accomplish using the proper solder hole method, as the connector is intended to be used.

I think a PL-259 connector needs to be designed for this technique.  The body of the connector should have a smaller inner diameter in order to fit the diameter of the RG-213 dielectric.  The outer part of the connector body where the braid is soldered to it could be of a smaller diameter as well and perhaps have a gnarled surface in order to promote better adhesion of the solder.  I would like to see some sort of rubber gasket employed with the threaded sleeve for some weatherproofing, however I can’t think of a good way to implement this without affecting the electrical connectivity to the body.

Unfortunately I’m more a software guy and not very good at fabricating metal parts.  Someone with manufacturing experience could probably design this connector and perhaps make a small fortune.  It’s problem waiting to be solved.

Is There An App for That?

~ radioartisan ~ 4 Comments

We’re hearing talk these days of the “Post-PC Era” when devices like the iPad, tablet PCs, and smartphones along with cloud-based applications will ultimately replace the PC.  I don’t totally buy into this as these devices don’t have the form factor or horsepower to replace the PC, at least in business environments.  I do think that the venerable tower PC, outside of gamer circles, will die.  It used to be standard to select a tower PC based on the number of expansion slots and bays, and it was once common to upgrade processors for more horsepower.  Those days are gone and more people are using one-size-fits-all laptops or appliance-like desktop machines, and when they’re three or four years old they’re tossed out for the latest model that can run Microsoft’s latest OS and office suite.

For over the last 15 years, when you bought a PC you by default got Microsoft’s OS, Windows and usually Microsoft Office or Works.  This symbiotic relationship has been dubbed “Wintel”, symbolizing the combination of Windows and Intel-based hardware.  Of course Linux has made inroads over the years but despite what Linux advocates say, it’s never passed the philosophical litmus test, being able to be run by your grandmother.  It continues to be the darling of techies’ desktops and runs the Internet behind the scenes.

With applications heading to the cloud and developers needing to support multiple devices running different operating systems, applications are more and more running in virtual machines such as Java rather than on the bare OS.  HTML 5 is supposedly going to revolutionize web applications, bringing functionality that was previously limited to Flash applications into HTML, an open language that is universally supported.

Amateur radio in my opinion has always had an odd relationship with software, that somewhat has its roots in the mindset of 1980’s DOS PC computing.  It wasn’t until the early 2000s that some of our most widely used logging and contest programs offered Windows replacements of their DOS ancestors.  Our free software authors never quite embraced open source, opting more for free-as-in-beer / freeware.  Nearly all notable amateur software is Windows/PC based.  There is some software for Mac and Linux, but it’s more a novelty.  I’ve found Linux ham radio software, especially logging programs, to often be someone’s experiment with making a database frontend rather than a concerted effort to build a major software application, like Ham Radio Deluxe or DXLab.  I know this will raise the angst of Linux users, but if you want to run amateur radio applications with full functionality, it’s tough to not use a PC running Windows.  I’ve tried about five times to switch to Linux in the shack and gave up.  I would love to buy a Mac, but I would still need a PC to run my amateur apps.

There is a paradigm shift in software coming.  The PC/Windows world is coming unseated.  It’s not going away, but it’s not going to be the default “no-brainer” choice that it used to be.  While we have many fine commercial and free software offerings, we’ve failed miserably in making cross-platform applications.  Even our networks like Winlink, D-STAR, IRLP, and APRS are vertical “silo” applications, some tied to specific OSs or hardware, or just outright ignore open standards.

Enter the Raspberry Pi, a very inexpensive single-board computer that is for supporting economical computing in third world countries.  It’s quickly turning into the latest geek fad.  Never has such a small board had such computing power at such a low price, and despite being a full-fledged computer it may very well displace the popular Arduino on many experimenter’s benches.  It should be a very hot commodity in amateur radio as it’s cheap and open, and ideal for hardware hackers like us.  Here’s the kicker.  It has an ARM processor and it can’t run Windows.  The best programs we have can’t run on this device.

I don’t see the PC world ending very soon, but I have to question at what point we’re going to start sacrificing some opportunities due to our lack of cross-platform software and systems.  In the past when considering software compatibility, one used to ask whether you ran a PC or Mac.  Today you hear questions like, “Can I get that in my app store?”, or “Does it run on Android?”