First Mobile QSO Party

Larry-K5END

Running power leads from the battery through the firewall, mounting the antenna in a manner to minimize radiation losses, safely, getting coax and the antenna control cable from the interior to the antenna, choking the antenna control cable, mounting the radios, separator kits and control heads, configuring the computer interface, GPS and PC-keyer, setting up to use a laptop PC ergonomically, planning and posting a route, choosing (and learning) contest logging software, learning what to actually DO (and what not to do) in a mobile contest and getting up to speed on Morse code—all in time to meet the deadline of the QSO Party weekend sums up the challenges faced in the two weeks before the Oklahoma QSO Party. This article covers the work on the exterior of the vehicle.

The most critical aspect was getting the best radiation efficiency possible with the antenna used, and mounting it safely was the foremost requirement. (Selecting the best commercially made antenna model for mobile installation is not within the scope of this article and not part of the discussion.) Much thought was given to the HF mobile antenna installation challenges with this Ridgeline. The first step was to choose a mount location. Drilling holes in a nice shiny vehicle was never a problem for this owner, provided it yielded a benefit and did not present a safety hazard. Punching a hole in the roof or trunk lid on this vehicle is, however, problematic for several reasons: the antenna weight and associated moment and torque plus the wind loading of the coil, mast, whip and capacity hat will induce stress at the base that could easily deform the sheet metal--and the mount would fail; this vehicle's sunroof, track and motors, side curtain airbags, satellite radio receiver, AM/FM antenna and other components integrated with the roof further prevent a roof mount, and even though the Ridgeline has a trunk lid, it is within the well of the bed and not the best location choice. Many Amateurs with pickups mount the antenna on the bed interior corner. This is generally accepted as a compromise, and this author's goal was to avoid such compromises. Mounting the antenna base next to and beneath the plane of the cab (or on the hitch mount) presents unwanted capacitive coupling directly to the vehicle body, therefore base height is the goal.

A custom roof rack with a metallic plane bonded and parallel to the ground was considered, yet the roof rack would increase wind drag, and motor vehicle height limitations would shorten the length of the radiating element, if only a bit. Mounting the antenna base at or just above the plane of the bed rails seemed like the optimum choice. A sturdy bed rail mounting system appeared to be the most feasible method. However, the after-market bed rails available were unsuitable. Painted strut framing channel secured to the bed rail with panel rivets provided a straightforward and novel approach.

But this pickup is unlike others. The bed sides and rails are curved in all dimensions; therefore great care was needed to drill holes in three layers of material, separately, while avoiding damage to vehicle integrity and mount straight framing channel. Proper hole placement and alignment presented the biggest challenge of this project, but only for one side. This bed is almost entirely symmetric, so after the passenger side was completed accurate templates existed immediately to do the driver side.

Drilling the holes in the right places was a real trick.

The bare metal left from drilling new holes was painted with factory matched touch up paint, more for corrosion resistance than for cosmetics.

A special tool is used to keep the panel rivet from turning during installation.

The panel rivets are zinc coated for corrosion inhibition, yet there didn't seem to be a reason not to paint them the factory color as well.

The hard part is over!

During the installation the bed rail framing channels were bonded to the vehicle body to improve antenna efficiency. The vehicle body and antenna base assembly are bonded throughout. Some edges of the copper bonding strips between the members are visible in the photographs.

One corner of the copper bonding strip is visible underneath the bracket in the right of the photo.

A stainless steel plate serves as the antenna base. The underneath side is unpainted and rests along copper strips which bond it to the cross members.

To make the contest in time, a temporary shortcut was chosen for the coax and antenna controller bulkhead. A piece of acrylic pane was cut and drilled to fit in the Ridgeline back window in such a way that it would not fly out. Coax bulkhead connectors and weather sealed grommets were inserted and reinforced for the transmission line and the antenna controller cable.

This temporary “shortcut” worked surprisingly well. Note the ferrite chokes on the coax and antenna controller cable. Chokes were also fitted at the antenna base.

The LT antenna was made more efficient by adding a mast extension above and below the coil, a capacitive “hat” and whip, all within an inch or so of the State motor vehicle height restrictions.

(Photo taken after contest.)

The antenna base mount turned out to be solid. Guy lines and turnbuckles were added to reduce swaying.

There was no time to spare before the contest began, but everything was working in time to participate and a few exchanges were made. The following narrative of the 2009 Oklahoma QSO Party Rover participation is taken from the author's journal.

March 17.

I've asked Dad if he were interested in driving for me in the OKQP, and he accepted. This will also give us a chance to visit some family and see some familiar places. He seems eager to go. This is going to be interesting, and a learning adventure...This is my/our first rodeo, so to speak, in mobile contesting.

March 23.

We did ride the whole 8 seconds during this "first rodeo," and it WAS the "learning adventure" predicted, and MORE.

The arrival of some materials needed to complete the mobile install was delayed until 6 PM Thursday, so I spent the rest of the night and Friday morning getting the vehicle ready. By that time I'd been up for 30 hours, so Dad was elected to drive on the way up. We departed around Noon Friday and checked into the Cheyenne Motel around 10:30 PM Friday...we had our Saturday morning breakfast at the Cheyenne Rockin' 'S' (cattle brand, not rock music) Cafe, (I had) a tasty Denver Omelet and (Dad had) a mountain of blueberry pancakes... Before we were ready to go, I discovered some show-stopping problems... (Requiring a few hours to correct) ...We stopped by the homestead farm nearby--as this was an ancillary objective of the trip. We also faced an unexpected obstacle of a bridge out, so we had to backtrack. I don't even know what time it was by then, but we were way behind schedule.

The VA QSOP was dominating the phone section of 20 meters, which led to my realization I'd left the shunt coil for matching 40 meters unterminated at the base. At this point I did NOT want to stop the vehicle. The analyzer said the antenna was resonating with good impedance across the 20 meter band, so I opted for 13 WPM CW circa 14.045 MHz. We were in the second county of the route by the time the first exchange was logged. Then I had the new experience of being at the bottom of small pile ups (do three simultaneous stations calling count as a "pile up?") I'd never "run" before, so I chose to listen to other "search-and-pounce" exchanges a bit to attempt to get the hang of it. That didn't help much, because very few ("none") were at 13 WPM or slower. We worked a few in the QRN (even with none of those nasty old power lines for miles) and somehow made it through the confusion I had over whether stations were calling me or someone else. I didn't know what to do except use the paddle and manually send "their-call-sign-plus-?" to which I'd hear "R R" and get the exchange. Time flies as fun is had, and I realized with a sinking, faux-pas feeling at 6:30 PM CDT we were going to be late for our dinner engagement with family just across the border in the State of Texas. We opted to skip the remainder of the route and stay in Ellis County. We turned West, drove a bit and parked on the shoulder just inside the Oklahoma border to work the few more that added to the diminutive log for the day.

...there is a drought up there right now...While we were parked on the shoulder near the border several cars...made double-"U" turns...to give us the once over, then once again, over, again. Finally, someone stopped and asked if we were chasing "that storm," and pointed vaguely to some mediocre clouds in the Northwest. My reply of "what storm?" did not appear to be encouraging news for them... QRN and QSB became serious foes and the contacts slowed down from snail's pace to zero. It was 7:00 PM and clearly, it was time to go. We arrived late for supper...but we did get there before dessert. As others had their bread pudding, I had grilled catfish, fresh bread, grilled squash and a lone pepper that had a heckuva lot more zing than I'd expected. And then bread pudding, of course. With coffee. I think my dad had a steak but I was too busy eating to notice.

The points scored for the day were greater than zero, but that is as much numerical data I will disclose. The bottom line is, we did get to Oklahoma and “QSO-partied" to WA, FL, NH, NY, NJ & CA all on 20 m CW, mobile. Imagine the feeling of working Staten Island, NY from a picturesque scene with the Sun setting over the plains, very much like the final images of the motion picture “Castaway," which, by the way, was filmed just a few miles down the road. It was my first time to do a mobile QSOP, first time to "run" in a contest and even the first time ever to do mobile HF--of any kind. It was my first time to crimp and assemble #8 AWG SB50 Power Poles, first time to violate a firewall, and first time to QSO with a screwdriver antenna. And it was fun. A lot of fun. My dad and I had a great weekend out, doing something we both enjoy. And we saw a lot of family. Therefore, I'd say that the entire experience fits my definition of an unqualified success. I'm ready to do it again--after some rest, that is.

This project/contest participation was done with the help of several experienced hams.

Many thanks to

Bob-KE5WUP

Chuck-NO5W

Colin-KU5B

Marty-W5MF

73

Larry-K5END