Bracket for the GRA-7350TC Antenna

Regular readers of this blog know that my homebrew 19-ft vertical is my go-to antenna for “stationary-mobile” operations. I use a low-tech mounting system in the bed of my truck involving a plastic milk crate, a cargo bar, and some bungees. When we go on our annual vacation to North Carolina, unfortunately, I have to remove the crate to free up storage space. I plan to activate a park or two while on vacation this year, so I wanted to come up with an alternate antenna arrangement.

I bought the GRA-7350TC antenna with this specific scenario in mind. Previously, I tested this antenna with a magnetic mount that I had stashed away in the basement. Although a couple of successful POTA activations proved its viability, I wanted something better than my little mag mount. 

Browsing around on Amazon, I found a stainless steel bracket with an SO-239 to ⅜-24 mount. I was reluctant to drill holes in my truck, but I thought a couple of small holes in the truck’s bed wouldn’t be too bad. So, I placed an order.

The Sirio stainless steel antenna mounting bracket I found on Amazon
The Sirio M1 stainless steel antenna mounting bracket I found on Amazon

The bracket arrived the next day. It’s really heavy-duty and possibly overkill for my application. My local hardware store had an excellent selection of stainless steel hardware. I bought some #12 x 1-inch sheet metal screws and some star washers. 

The next step was figuring out exactly where to mount it. I had to make sure that I could still close the truck bed cover without hitting it. By dumb luck, I chose a spot where I could use one of the screws that fastens the truck’s bed liner. This placed the mount close to where I wanted it. Then, it was a quick task to drill pilot holes for the three additional screws. Mechanically, it felt solid, and an ohmmeter check confirmed continuity to the truck’s body. 

The bracket installed in the bed of my truck with the antenna installed. The black screw is an existing screw I took advantage of.
The bracket installed in the bed of my truck with the antenna installed. The black screw is an existing screw I took advantage of.

I gave the new mount a trial run at Ridley Creek State Park (K-1414, KFF-1414). It took me about a minute to get the antenna set up on the mount, and it was a perfect fit. I ran an 18-foot length of RG-8x coax (much longer than I really needed) to the Penntek TR-35 inside my truck.

Using an antenna analyzer, I first tuned it up on the 40M band. I couldn’t get the SWR down below 2:1. This also happened when using the antenna on a magnetic mount, too. I’m guessing a different length of coax or a counterpoise wire might help. In any event, I tuned the antenna to resonance and used a tuner to keep the rig happy. The first QSO was a station in Georgia who gave me a decent signal report. 

The Gabil GRA-7350TC antenna in use
The Gabil GRA-7350TC antenna in use

The SWR on 30M was a bit lower but still above 2:1. Again, I had no problems making contacts with the antenna. On 20M and 17M, the SWR was down to about 1.2:1 or thereabouts. 

Despite the time spent fiddling with the antenna, I logged 13 contacts, with three park-to-park QSOs. I also worked W1HNJ on 40M and 30M. As part of Museum Ship Weekend, they were operating the radio console from the hospital ship, SS Hope. The radio console is now part of the Chatham Marconi-RCA Wireless Museum on Cape Cod, Massachusetts. 

I still have some tinkering to do, but I think the mounting bracket will work just fine. I won’t be retiring my homebrew vertical anytime soon, but the GRA-7350TC gives me another option when the need arises. 

73, Craig WB3GCK

Holiday Weekend Activities

Memorial Day marks the unofficial start of summer here in the States. Although I had some family activities planned over the three-day weekend, I squeezed in some QRP-portable operations. 

POTA at Marsh Creek State Park

On Friday, I drove over to Marsh Creek State Park (K-1380, KFF-1380) for an activation. I figured it wouldn’t be too crowded on a Friday, but I was wrong. 

I wanted to operate from one of the picnic tables overlooking the lake. When I got there, folks getting a jump on their holiday picnics had already claimed them, so I ended up operating from the truck. I gave my newly acquired Gabil GRA-7350TC antenna another try, using the old magnetic mount I used last week. Like last week, I used my TR-35 transceiver at 5 watts.

My location at Marsh Creek State Park (K-1380, KFF-1380). The GRA-7350TC is mounted on the roof of my truck with a magnetic mount.
My location at Marsh Creek State Park (K-1380, KFF-1380). The GRA-7350TC is mounted on the roof of my truck with a magnetic mount.

Band conditions were less than stellar on the lower bands, but a mini pile-up promptly greeted me on 40M. After logging a few quick contacts, things slowed down considerably. I spent most of my time on 30M, where band conditions seemed a little better. I also did some hunting on 20M before packing up. I finished up with 20 QSOs in the log, including five park-to-park contacts.

I don’t think the GRA-7350TC performs as well as my homebrew vertical, but it sure is easy to set up. Although I can set up my homebrew vertical in under three minutes, the Gabil antenna goes up even faster. 

By the time I left, the parking lot was nearly full. I guess people were eager to get their long weekend started. 

Bike-Portable in the Park

On Saturday, I went for a short bike ride on the Schuylkill River Trail. This was my first time on the bike since my latest round of knee issues sidelined me back in March. Before heading out, I threw in my TR-35, Elecraft AX1, and bike mount

I started off from a trailhead parking lot close to Towpath Park—I didn’t want to overdo it with my knee. A mile and a half later, I was in the park setting up the radio. I set up the radio on a park bench near the remnants of the Schuylkill Canal and mounted my AX1 on the bike’s handlebars.

My park bench setup in Towpath Park
My park bench setup in Towpath Park

I planned to do some POTA hunting on 20M, but I found the band was wall-to-wall with contesters. I worked one contester in Wisconsin on 20M, but I had no success beyond that. My 5 watts and 40-inch whip was no match for the high-power contest stations in pile-ups. I checked 17M, but I didn’t hear much of anything there.

My view of the old Schuylkill Canal in Towpath Park
My view of the old Schuylkill Canal in Towpath Park

With one meager QSO in my log, I packed up and continued on my ride. It sure felt great to be back on the bike again. While I didn’t do so hot on the radio, my knee held up great on my short three-mile ride. I’m looking forward to longer rides.  

Valley Forge POTA Activation

On Monday, I headed out early to get in a quick POTA activation at Valley Forge National Historical Park (K-0761, KFF-0761). I rolled into one of the picnic areas and found a nice shady parking spot.

My shady parking spot at Valley Forge National Historical Park (K-0761, KFF-0761)
My shady parking spot at Valley Forge National Historical Park (K-0761, KFF-0761)

As I was setting up, a gentleman walked up to ask about my antenna on the back of my truck. I gave him a quick explanation of ham radio and Parks on the Air. Normally, passersby would just thank me and move on. This fellow, however, tried to engage me in one of the most bizarre conversations I’ve ever heard. After a few minutes, I politely disengaged myself from his rambling and got on with my activation.

Today, I used my TR-35 and my 19-foot homebrew vertical. It took about 10 minutes to log my first 10 contacts on 40M. In a little more than an hour, I logged 23 contacts on 40M, 30M, and 20M. There were lots of activators out and about this morning; I made seven park-to-park contacts I know of. 

All in all, I had a good weekend, and the weather was spectacular. I hope you all had a wonderful weekend as well and took some time to remember those who gave their lives to protect the freedoms we enjoy. 

72, Craig WB3GCK

POTA with a New Antenna

I looked at my log the other day and saw that I had only made a measly two HF contacts this month. Between the grandkids’ school functions, soccer games, horseback riding competitions, and my knee issues; I haven’t had much time for my QRP-portable activities. I set out to change that this morning with a drive to Valley Forge National Historical Park (K-0761, KFF-0761).

A few weeks ago, while nursing my injured knee, I made an impulse purchase. After watching some YouTube videos, I went on Amazon and bought a Gabil GRA-7350TC antenna. The last thing I needed was another antenna—I blame YouTube and Amazon. Actually, it wasn’t a totally frivolous purchase; I have plans to use it during a trip later this summer.

I also bought the matching GRA-ULT01 MK3 tripod for the antenna, which I planned to try out today. I put together some radials to use with the tripod setup. 

As I headed out the door this morning, I grabbed an old magnetic mount base I had from an 2M/440 antenna. Since I bought the GRA-7350TC with the ⅜-24 stud mount, the antenna was a perfect fit for the mag mount. I figured I’d give that a try, while I was trying out the antenna.

It was raining when I got to the park this morning, so I kept things simple and tried out the mag mount. In doing so, I learned something about my six-year-old truck: The hood isn’t made of steel. The rest of the truck is, but not the hood. Who knew? (Probably every Chevy Silverado owner but me, I guess.) I ended up putting the antenna on the roof where I could easily reach it. Inside the truck, I used my Penntek TR-35 (5 watts).

The Gabil GRA-7350TC on a magnetic mount from an old 2M/440 antenna.
The Gabil GRA-7350TC on a magnetic mount from an old 2M/440 antenna.

The sliding coil adjustment made tuning up a snap. Using my old MFJ-226 antenna analyzer, it only took a minute or two to get the antenna tuned up on 40M. I’m not a big fan of having to take an antenna analyzer out in the field, but this was relatively painless. Band changes only took about a minute. Most of that time was setting up the antenna analyzer for the band of interest. 

I used the new antenna on 40M, 30M, and 20M with decent results. In the end, I had 16 contacts, including five park-to-park QSOs. I’m sure my little magnetic mount wasn’t providing the best ground in the world, but at least I know it’s usable in a pinch.

Hopefully, June will provide more opportunities to get out portable. Since my old knee has been feeling a little better recently, I’m hoping to get back on the bike again at some point. I already have some ideas for a bike mount for the GRA-7350TC. 

73, Craig WB3GCK