JSCARC Fox Hunt #3 Report

Under clear skies and plenty of sunshine, the JSCARC Fox Hunt #3 was successfully conducted on Sunday Jan 22.

I ended up selecting the League City Walter Hall Park, a gorgeous 86 acre park with plenty of trees and easy driving access within to install hidden foxes.

A 2m 1w Fox beacon (Baofeng UV-R5 + 3800 mah battery with Byonics BFoxCon controller) was driving an Ed Fong PVC J-pole antenna strung up high 15’+ into a tree so that the 146.565 signal could be easily received 4 miles away from the JSC W5RRR shack.

Three 80m foxes (as used previously) were crystal transmitters based off of ON7YD’s design and driven by the popular ATTiny85 controller with software designed by John AB5SS.  From the last Fox Hunt in Dec, John mentioned that one of the 80m foxes signal was weaker than the rest.  Upon inspection last week, I discovered somehow I had accidently melted a chunk of the polyfilm variable capacitor tuner plates with a reckless pass of my soldering iron during the initial build.  Got it fixed, so all 80m foxes were screaming at a healthy 2W apiece today and for future hunts.

The setting up of the foxes took about 1.5 hours pre to the activation.  I used a fishing pole + 1/2″ hex bolt sinker to string the antennas into the trees.  I tried to find trees close enough to the pathways, but not directly obvious to the traffic.  Because it rained the day before, there were lots of ant hill mounds by the trees, which I also tried to avoid.

Both John AB5SS and Jeff AB4ME started at the get go around 12:00pm.  While monitoring the W5RRR 146.640 repeater, Dale KG5U reported hearing the 2m and 80m beacons from his QTH about 8 miles away.  Jayant KG5LJZ, also about 8 miles away, reported that he couldn’t copy the beacons from his QTH.  I’ll take that into consideration for future hunts- there’s an option to raise the power, but at reduced operating time.

After a hard fought ~1.5-2 hours of DFing (or did they stop along the way to eat a pizza?), both John and Jeff separtely found the park location and quickly made hay of locating the 4 foxes within the park.  Congrats to our fox hunters!  Here’s Jeff:

 

I found out afterwards that Chris AG5WN had been hunting for a few hours with his family, but couldn’t quite DF to the park.  Special congrats for him and his family’s tenacious effort.

Excerpts from w5rrr.groups.io

Chris AG5WN
The Nelson family did not find the foxes today. Three and a half hours and we ran out of time. We got stuck at Nassau Bay Park and primarily my narrow mind. 

We first picked up the signal at the NASA Hilton, it grew stronger into Nassau Bay and started to fade as we left. Convinced it was at the park, we spent a couple hours walking the whole park with the boys on 80m and me on the 2m signal. Determined we were close but limited by the creek we headed across to the nature trail off Egret Bay but ran out of time. 

Based on past fox hunts, I should have known the broad area covered by the foxes and should have honed in on taking a drive to another periphery spot to see if we could narrow in. I did fail to prepare with a map, so we were just off the mark today BUT had a blast and are very grateful to W5OC for putting in the work to set up some foxes for us!

Jeff AB4ME
… I started by following John’s excellent suggestion to use the satellite station in the shack to get an initial 2m vector. That gave me a general direction. I stuck with 2m and took vectors at Academy on I-45, further down I-45 near 96, back up I-45 near 518, then near Texas Ave and NASA Pky. One of the vectors was completely wrong and the remainder didn’t intersect nicely and neatly, but they were close enough to get me to the right park.

John AB5SS
… The 2m Fox was easily heard from the shack and most parts of the 7mi radius boundary.  I started my hunt at the W5RRR shack and used the satellite station to get a rough bearing to the southwest on the 2m fox.  I then went over by Academy to get a cross-bearing and it was to the southeast.  Really strong signal by Academy.  Looking on a map, if figured he put them at a school and looking along that bearing I figured maybe Clear Falls HS, so I started driving and went right past Walter Hall Park.  I should have realized my mistake when the signal started getting weak but a plan is a plan, so arriving at CFHS, I could barely hear the 2m fox 🙁  So took another bearing and headed back into League City, stopping at Clear Creek HS for another bearing and pointed me towards the little park in the middle of LC.  Signal was really strong there but was able to DF using my HT & body block method and pointed me towards Walter Hall Park.  Headed to the park down on Houston Street, which comes out on Hwy 3 across from the north entrance to the park, and saw the flag on one of the 80m foxes.  Bingo!

After I got to the park I started to chase the 2m fox but got distracted looking for 80m foxes.  Jeff, AB4ME, showed up and we both started searching for the 80m foxes.  Dave was there and after a quick chat, I set out to find the last 80m fox, and then on to the 2m fox.  At the last 80m fox location, I used the yagi and lots of attenuation and got a bearing.  Driving through the park, I finally got close enough to hear the 3rd harmonic (439.695 MHz) on my HT, used the body blocking method again, and finally found the last fox.  Dave had strung the 2m antenna up about 15′, so no wonder it was easy to hear from a distance.

Fun event!  Wish we had more hunters and I encourage more club members to give it a try next time Dave puts on a hunt.  You really can DF with just an HT and using your body to block the signal.  Or a foil coated Pringles can with a slot cut in it, as another member has successfully done.  For the 80m, Dave has a pile of DF receivers he has graciously offered to loan out and they work very well.  …

Here are my takeaways

1.  I need a proof reader.. Jeff AB4ME informed me during the hunt, that I posted the wrong frequency for the 2m beacon.  Oops, embarrassed.. 145.565 posted, should have been 146.565.
Fortunately, I did post the correct frequency in the w5rrr.groups.io notices.

2.  The technique (thanks John AB5SS) of using the shack’s 2m sat antenna to get an initial bearing is brilliant.  Good tip for future hunters!

3.  John also showed me his tape measure beam.  The nulls this antenna produced were deep and narrow, absolutely perfect for DFing the 2m signal.  We’ll plan to build this same antenna as a club DIY nite so everyone can be equiped with the high performing, and inexpensive capability for future fox hunts.

4.  I’ve been placing goody rewards (candy) at each fox location by having a plastic bag around the tree trunk , but may not continue this in the future.  Upon closing down and retrieving the last fox, I saw a squirrel scampering away from the tree used by the beacon setup.  As I got closer, I found the bag of candy (Hershey Kisses) still strapped to the tree trunk, but it had been partially torn open and there was a 20′ trail of aluminum kisses wrapper fragments leading toward another tree.  There were still a few remaining candy kisses in the torn open bag, but most were gone.  As I was cleaning it up, a pesky squirrel was barking at me for intruding with his chocolate heist.

Today demonstrated a very fun aspect of ham radio.  It promotes learning about the characteristics of RF (directionality, reflections, range, antenna performance, etc) as well as an incentive and opportunity to build and improve equipment.  I hope others might find a chance to give it a try and partake in the fun.  Many thanks for the participanting folks today (AB5SS, AB4ME, AG5WN+ family, KG5U, KG5LJZ).  And special congrats to KE5QG for locating his virtual fox online. 😉

73
Dave W5OC