Captain John Smith Trail with the Gabil GRA-7350TC Antenna

My (far) better half and I spent the weekend in Central Pennsylvania watching the grandkids, while our second harmonic and her husband were off celebrating their anniversary. Of course, I took some radio gear along to do some QRP-portable operating while I was out there.

I had a brief window of opportunity on Saturday morning, so I drove to the Falmouth Access boat launch along the Susquehanna River to activate the Captain John Smith National Historic Trail (US-4567). Since we used the (far) better half’s car this weekend, I used this opportunity to try out my Gabil GRA-7350TC vertical and magnetic mount on her car for the first time. I also brought along my trusty Penntek TR-35 (5 watts, CW).

The Gabil GRA-7350TC & mag mount on my (far) better half's car, while activating the Captain John Smith Chesapeake National Historic Trail (US-4567)
The Gabil GRA-7350TC & mag mount on my (far) better half’s car, while activating the Captain John Smith National Historic Trail (US-4567)

To facilitate tuning the vertical, I used a recently acquired Mini60 analyzer I bought off AliExpress. It’s cheap and a little quirky, but it’s small and its simple SWR readings got the job done. I started on 40M and got the SWR down to 1.3:1 without adding radials. That’s better than I had ever gotten on my pickup truck. I guess the roof on my XYL’s little SUV provides a better ground plane than my truck.

The Mini60 Antenna Analyzer. I found a case on Temu just the right size to hold Mini60 and some accessories.
The Mini60 Antenna Analyzer. I found a case on Temu just the right size to hold the Mini60 and some accessories.

Band conditions were generally lousy, and there was some horrendous local noise in 40M and 20M. I didn’t experience any noise issues the last time I activated from here. Despite all that, I managed to scrape together 17 contacts in about 35 minutes, including one with F4ILH on 17M. Also, thanks to W5KEB for working me on two bands. (My apologies to a couple of hunters I couldn’t pull out of the crazy noise in 40M and 20M.)

Even though the bands weren’t too hot, I was pleased with the performance of the Gabil antenna. It’s another good antenna option when I’m using my (far) better half’s car (or any car, for that matter). 

72, Craig WB3GCK

Adding Radials to a Mag Mount

Reading through some blog posts recently, I came across an interesting idea from John AE5X. In the comments section of a recent post, John mentions adding a ground stud to a magnetic mount. The ground stud allows him to connect two ¼-wave radials (for 20M) for his MFJ-1979 telescopic vertical. So what follows is my implementation of John’s clever idea. 

On occasion, I’ve used my Gabil GRA-7350TC vertical with a small magnetic mount salvaged from an old 2M/440 antenna. I plan to use this configuration on my (far) better half’s car while visiting family over the holidays. The mag mount is only 3.5 inches in diameter, so I’m sure it’s not providing much of a ground connection. While the Gabil vertical is certainly usable with this mount, I’ve always felt that it needed more of a counterpoise on 40M and 30M to obtain a better match. I figured John’s idea might be the way to go. 

Since I needed to drill a hole from inside the mount, I had to remove the foil covering from the bottom of the mount. This magnetic mount is probably around 25 years old, so removing the foil wasn’t too difficult. Using my pocket knife, I was able to peel the foil off, while keeping it intact. 

Next, I drilled a ⅛-inch hole through the ground plate and out through to the top of the mount. It was a tight squeeze, but I was able to get a 4-40 bolt and a star washer in there. On the outside of the mount, I used a nut and lock washer.

Interior view of the magnetic mount. It was a tight squeeze, but a 4-40 screw and star washer just fit in there.
Interior view of the magnetic mount. It was a tight squeeze, but a 4-40 screw and star washer just fits in there.

The final step was to re-apply the foil covering on the bottom of the mount. I used some rubber cement to reattach it. I don’t know how well the rubber cement will hold up over time, but it won’t be seeing heavy use. It seems fine so far. 

Exterior view of the old magnetic mount. I later removed the second nut from the screw I installed.
Exterior view of the old magnetic mount. I later removed the second nut from the screw I installed.

While I was at it, I replaced the PL-259 connector. The years had not been kind to the connector that was on there. 

I gave the modified mag mount a try during a recent activation at US-1380, KFF-1380. I used the GRA-7350TC and mag mount on the roof of my truck. With no counterpoise wire attached, the best match I could get on 40M was just a hair under 3:1. 

Next, I attached a 33-foot counterpoise wire to the mag mount. I ran the wire off the back of the truck and onto the ground. To avoid creating a trip hazard for others, I wrapped the wire around the side of the truck. In this configuration, I got the SWR down to about 1.2:1. Success!

The Gabil GRA-7350TC and magnetic mount with one 33-foot counterpoise attached. The wire dropped to the ground behind the truck and wrapped around the side.
The Gabil GRA-7350TC and magnetic mount with one 33-foot counterpoise attached. The wire dropped to the ground behind the truck and wrapped around the side.

Using the same counterpoise, the best I could do on 30M was a little under 2:1. I tried two 16.5-foot wires, but the result was about the same. No worries. An SWR of 2:1 is a piece of cake for the Elecraft T1 tuner. 

In this configuration, I had two 16.5-foot counterpoise wires attached.
In this configuration, I had two 16.5-foot counterpoise wires attached.

I ran the entire activation on 40M and 30M with great results (40 contacts in less than an hour). In fact, it was the best I have done with the Gabil antenna and mag mount. Was it because of the counterpoise wire? Maybe. Regardless, my five-watt signal was getting out just fine with this thing.

Thanks again to John AE5X for the inspiration.

72, Craig WB3GCK

Weathering the Storm

While still on my extended stay at my daughter’s house in central Pennsylvania, I wanted to do some casual operating. So, I set up in the backyard to make a few contacts.

Today, I decided to give my Gabil GRA-7350TC vertical some air time. It’s been a while since I’ve used it. I set it up using the Gabil GRA-ULT01 MK3 tripod. I had forgotten how well engineered the Gabil stuff is. Anyway, I used four 15-foot speaker wire radials spread out on the ground. For the coax, I used 20 feet of RG-174.

My Gabil GRA-7350TC vertical on the Gabil GRA-ULT01 MK3 tripod
My Gabil GRA-7350TC vertical on the Gabil GRA-ULT01 MK3 tripod

I started out on 40M. Using an antenna analyzer, I got the SWR down as far as I could and let the KX3’s tuner do the rest. Taking a quick dial spin down the band, I didn’t hear much at all. Eventually, I came across WA2NYY activating a park in New York and called him. Despite the horrendous band conditions, he heard my 5-watt signal on the first call. Next, I heard an activator in North Carolina, but I had a rough copy. We still managed to complete the contact.

My KX3 and 6Ah LiFePO4 battery
My KX3 and 6Ah LiFePO4 battery

I then moved up to 20M and found the same crappy conditions. Eventually, I found and worked two more POTA activators.

I checked the POTA spotting page and saw that there were a couple of European activators on 15M. I tuned up the antenna and did a quick check. Nothing but dead silence across the band.

It was at that point that I checked the band conditions online and saw that there was a severe geomagnetic storm in progress. It showed poor conditions on all the HF bands. That certainly explained the lousy band conditions.

This explains the lousy band conditions today.
Yikes! This explains the lousy band conditions today.

Not being a glutton for punishment, I shut down for the day. Still, I was thankful for the four contacts I made with five watts of CW into an eight-foot base-loaded whip during a severe geomagnetic storm.

72, Craig WB3GCK

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