Lessons Learned, second in a series. Cars are not trucks.

When I last posted, I had a half-installed antenna, a box of parts, and a bald spot from scratching my head trying to figure out how to put it all together. I now had the stud I needed, but it didn’t fit my car. The one I got was made for a truck, probably an 18-wheeler. Petro is, after all, a truck stop, not a car stop. I searched around some more and ordered what I needed, and some other stuff because, as long as I was spending money, why not.

One of the more awesome things about this community is that chances are, if you’re trying to do something, someone else has already done it and has written a blog with photos, posted a YouTube video, or has commented somewhere about it. Alan Applegate, K0BG, has a very detailed website, K0BG.com , that has just about anything you would ever want to know about mobile operations. One of the things I learned about is a nifty box called a RigRunner that is nothing more than a power strip for ham radio equipment that uses Anderson Powerpoles for both input and output and has fuses for each of the sockets. This turned out to be a perfect solution for me for three reasons. The first is that I already had a wiring harness from the battery to the cabin that had powerpoles already on it, so that took care of the input. The second is that my car is notoriously difficult to run anything from the battery to the cabin, and I wasn’t about to do it for the antenna’s motor control switch, so I took K0BG’s suggestion and hooked it up to powerpoles and from there, to the RigRunner. Easy-peasy rice and cheesy! The third is that I can be truly mobile. I don’t have to disconnect and re-connect a bunch of things if I want to change cars or do a demonstration. I can simply pull the antenna off the mount, pull the cables and the radio, hook a single connection to a single power source, and go from there.

I spent a few days in between rain showers and snow and got the antenna and radio up and working. The radio has to be mounted to a permanent location in my car, and I’m thinking about installing the brackets to the back of the back seat so it’s in the trunk and out of the way but still easily accessible. But that’s a project for a day off.

Lessons Learned – First in (I hope) a series

Not long ago, I was able to purchase some equipment, and by “some equipment”, I mean enough for an actual shack, an HF mobile rig and antenna, and the accessories to go with them. You know – the first rig. Buying a rig is a lot like buying a car. You look at the pretty ads, you think about what you want, you figure out how much you can afford, and you (ideally) do your homework so you get the right rig at the right price. I did just that. Sort of.

When it came time to look for a mobile HF antenna, I asked around for recommendations. I settled on one and ordered it online. What I didn’t do is ask the one question I should have, and that was “Is there anything else I’m going to need with this?” Because of course there was, and I’ll get to that in a minute.

I set aside a nice Friday afternoon to install the antenna and radio because John, W3HMS had agreed to bring his antenna analyzer to the ham breakfast. I had the recommended (sort of) mount, antenna, and cables. I started with Step One and stopped. I couldn’t see a place to attach the coax. There was a four-pin cable that runs the motor, but no coax connector. Hm. I might not be the brightest or most technically proficient ham, but I’m also not an idiot and I know there’s supposed to be a coax running from the antenna to the radio. I looked at the printed instructions that came with the antenna, I looked at what had to be a million photos of installations, and I could not figure out how I was supposed to connect the coax to the antenna. Finally, I posted the question to an online ham radio community I belong to to see if anyone could tell me something, anything, that would help. Lots of responses with links to the instructions I had in my hand, links to the photos I’d already looked at, and other, equally unhelpful information.

The next morning, I showed John the instructions that came with the antenna and he told me to call the company. When the guy whose vehicle looks like an FBI surveillance van tells you to call the company, things are not looking good. I left the breakfast early to call the company. I was NOT going to let this… this THING win. I left a voice mail for the technical support guy and went inside to watch the Olympics. After some snowboarding and a round or two of women’s biathlon, my phone dinged. Someone had responded to my question online, and he had helpful information! What I didn’t know was that the antenna required a 3/8-inch stud attached to a SO-239 connector. Aha! I jumped in the car, drove to the CB shop at the local Petro truck stop, and miracle of miracles, they had the exact stud I needed! Hallelujah! Unfortunately, it started to rain, so the installation is on hold for another day, but it will happen.

Ham radio is a fun hobby, and there is always a lot to learn. Sometimes, it’s how to use a new piece of equipment. Other times, it’s a little more basic. Next time I order equipment, I’ll make sure I have a list of all the accessories I need.

Emergency Management radio information

The Eastern Area office of Pennsylvania Emergency Management Agency (PEMA) is monitoring 3.9875 LSB.

Skywarn is on the Harrisburg repeater at 145.110,  pl code of 131.8.

Information from this morning’s net is as follows:

We had 22 participants, of whom 11 were on HTs,  two were using the SMRA EchoLink node, and ten were using other rigs.

There will be another net at 9 p.m. local time on the 145.43 SMRA repeater.

As an editorial side comment, events like this give us the opportunity to get into the public service side of ham radio. By collecting data from all over the repeater coverage area, we can give county, state, and federal emergency management agencies information they need to provide services such as snowplowing; police, fire, and medical services; and whether nonessential services should be shut down for the duration of the event.

Finally, ham radio is a way to call for help if you should need it. Cell service and power may fail, but a battery-operated HT or mobile rig is always available should you need it.

Stay safe and enjoy the time off!

-Robin, KC3CEK

A Simple 2 m/70 cm Vertical Dipole Antenna

A Simple 2 m/70 cm Vertical Dipole Antenna
This easy to build dual band VHF/UHF antenna makes a great project for the new ham that is ready to get on the 2 meter and 70 centimeter amateur radio bands. It can be mounted on a roof top for use as a fixed antenna and it also folds conveniently for travel making it an excellent backpack antenna. The design is simple and so is construction.

Construction
The antenna elements are made of 1/8″ diameter stainless steel rod. Each rod is bent into a tight “U” shape and fastened to the acrylic Plexiglas boom with stainless steel hardware. Flat washers large enough to fit across the gap in each element are used to hold the elements in place. A piece of 1/4″ thick cast acrylic Plexiglas, 18″ long and 2-1/2″ wide, is used for the boom.

Drill the holes in the boom as shown in the diagram. The position and hole size for the mast mounting clamp is determined by the size and width of the clamp or U-bolt that you use. I used a TV antenna mast clamp that fits a 1-1/4″ mast.

1

 

Probably the hardest part in making this antenna is bending the stainless steel rod. But the rod can be bent without heating it first with a torch. I was able to bend the rod by placing it in a bench vise. The tricky part is to bend two pieces of rod that come out looking similar is shape. Use two pieces of stainless steel rod that are longer than needed then trim them to correct lengths after the rod has been folded into a U shape. Make each element section as shown in the next diagram.

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The hardware for mounting the antenna elements to the boom is also used to connect the feed line to the antenna. The coaxial cable center and shield are separated and the leads kept as short as possible. Crimp-on ring connectors, with the plastic insulation removed, are soldered to the ends of the cable. The coaxial cable center lead is connected to the top section and the shield is connected to the bottom section of the antenna. This antenna was fed with RG-8X (Mini 8) 50 ohm coaxial cable. The feed line used was a random length and was not cut to any specific length.

Used mostly all #6 stainless steel hardware to attach the antenna elements to the boom. Start by placing an external tooth lock washer on a machine screw then insert it into the hole drilled in the boom. Next install a flat washer, then the antenna element, then another flat washer. The ring connectors with the coaxial cable attached go on next then finally fasten with a split lock washer and a wing nut. Repeat for the opposite side.

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Tuning the Antenna
To tune the antenna for minimum SWR simply loosen the wing nuts and slide the antenna elements in or out as needed. Keep in mind that changes made to one band will affect the other band. For example if you shorten the 2 meter length then you also shorten the 70 cm length. Some fine tuning by again trimming either the 2 meter or 70 cm sections may be done if desired but this should not be needed.

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Parts List
All stainless steel element mounting hardware. Use larger size hardware if flat washers do not extend across both sides of the antenna element.

  • 2 each 1/8″ Stainless steel rod, 3′ (.9 m) long.
  • Acrylic Plexiglas, 18″ x 2-1/2″ x 1/4″ (45.7 cm x 6.4 cm x 7 mm).
  • 2 each #6 x 32 x 1″ (25 mm) Machine screws.
  • 2 each #6 x 32 Wing nuts.
  • 4 each #6 Large flat washers.
  • 2 each #6 Split lock washers.
  • 2 each #6 External tooth lock washers.
  • 2 each #6 Crimp-on ring connectors.
  • Mast mount clamp.
  • Plastic cable tie or small U-bolt.