The Bristol County Repeater Association Amateur Radio Foxhunt Challenge #3

We are hooked. When Skip KB1CNB announces that the BCRA is going to have a foxhunt, our only question is “where?” Marc AA1F and I dragged Jeff AC1JR along with us for our third amateur radio direction finding event. The weather was exquisitely cooperative!

We met AC1JR at the Massasoit State Park where he was armed with a handmade yagi constructed of copper spokes on a wooden boom, a handheld radio, and a tablet. An 2m/70cm magmount omnidirectional antenna, an Arrow handheld 2M yagi, an Arrow 4MHz offset attenuator (found here), 2 Yaesu FT-4X handitalkies, a garmin handheld gps, and a laptop computer formed our radio direction finding kit. With his car safely parked, AC1JR hopped in our blue truck for the transmitter hunt.

Prior to setting out, I had identified the announced center point of the event (in Assonet MA) by marking a downloaded map with a red pin. The blue circle is drawn at a 5 mile radius around the published starting point. The “fox”, or in other words, the radio transmitter, would be in KB1CNB’s vehicle somewhere inside that circle. AC1JR had already confirmed that the fox was transmitting south of Massasoit State Park (as expected) by the time we picked him up.

As we drove around looking for the now well-known grey-blue jeep, we chose multiple locations to stop and take bearings. You can see the pink arrows on the map showing the various trajectories we had picked up. As we drove through the area around Myricks (a town I had never heard of!), the signal became loud and clear with very little static on the magmount antenna. We pulled into the drive of the Myricks airport where we caught a bit of attention from the locals as we retrieved our yagis from the truck bed.

We ran into Mike K1MJC who had also stopped to listen for the fox.

We would later catch up with K1MJC again at the finish line (pictured above), where he showed us The HANDI-Finder antenna kit he built. This antenna takes advantage of a null (with silencing of the transmitted signal) when pointed at the fox. It also has an optional tone built in that will silence when the antenna produces a null.

The radio direction finding process became quite interesting at the air field. The omindirectional antenna on top of the truck picked up the transmitter easily. AC1JR’s DIY yagi showed clear directionality with the strongest signal coming from the east. My Arrow yagi on the other hand picked up the signal strongly, but was too overwhelmed to show directionality anymore. I sorted this out by using the offset attenuator (shown below) and was able to confirm that the fox was transmitting toward the east. If you look at the pink patterned area on the map above, you will see what I mean.

In fact, if you take a peek at AC1JR’s map, you will see how incredibly accurate his bearings were. He’s numbered his starting at Massasoit State Park, with the last one (#7) at Myrick’s Air Field. If you are interested in making his yagi, I learned that not only does he have a blog, he has incredibly good directions on how to do so HERE! Thanks for sharing your map Jeff!

…and that’s when we remembered that we had passed by a Dunkin’ Donuts plaza on the way to the air strip! We had learned from previous events that Skip was a big fan of coffee. Sure enough, by the time we entered the parking lot, it was immediately obvious that the foxhunting gang had already beat us there.

Finishing another successful hunt was pleasure enough for us, but KB1CNB really put the icing on the cake this time! For our 5th place arrival, he awarded us with a 3D-printed coin, made to look like granite to reflect our “finisher” status, on a little stand. In fact, he even made a silver version for our 2nd place finish at the last BCRA foxhunt we attended in May! Thank you for the cool presents Skip!

After a few refreshments at the donut shop, we headed out. But not without a quick trip back to the Myricks Air Field, where we posed for some action photos specifically for this blog. We were so busy with the foxhunt, we neglected to take any along the way!

What another amazing time with our newest radio friends in the Bristol County Repeater Association! Thanks so much Skip for organizing these foxhunts — we are already looking forward to the next one!

Yours truly,

KM1NDY