Activation Report: Gamble Plantation Historic State Park (US-3625) — August 14, 2026

• August 14 2026
• 11 min reading time

A ten-contact morning at Gamble Plantation Historic State Park (US-3625) on 20m FT8 — 5 watts QRP into a hatch-mounted vertical, a locked gate that pushed the first QSO into the lot next door, and an hour spent discovering that a flat SWR and 158 reception reports say nothing at all about your receive path.

Mode: FT8 (Digital) · Band: 20m · Radio: Xiegu X6200 · Contacts: 10 · Park: US-3625

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A locked gate, an hour of receive troubleshooting in a parking lot next door, and ten contacts on 20 meter FT8 at five watts. The antenna was never the problem. My sound card was.

The park

The Judah P. Benjamin Confederate Memorial at Gamble Plantation Historic State Park (US-3625) sits in Ellenton, just off US-301. I rolled up just after 7 AM. I knew the park didn't open until 8, but what I hadn't accounted for was the gate — an actual closed gate, not a "park anywhere and wait" situation. This was always going to be a parking lot activation, so I found a nearby lot, backed in, and set up in the car.

Which turned out to be lucky, because I was about to spend the next hour not making contacts.

Clear sky, 79°F, and about 4 mph of wind. Solar flux 136 with a K index of 2.67 — 15, 17, and 20 meters all looking usable.

The setup

Hatch-mounted vertical on the back of the vehicle — the Harvest OUTB2000 HF/6M — with the Xiegu X6200 at 5 watts on the center console, DigiPi on a Raspberry Pi 4 running WSJT-X, and the tablet up on the windshield over VNC. Starlink for internet.

Loud everywhere, deaf at home

First thing I checked once the station was up was PSK Reporter. 158 reception reports for W4GGJ. Australia. Iceland. The UK. By any outbound measure the station was working beautifully — five watts from a hatch-mounted vertical in a parking lot in Ellenton was landing on three continents.

And I couldn't hear anybody.

This is the classic hear/be-heard asymmetry, and it's disorienting because every reflex you have says the antenna is fine. The map says the antenna is fine. The map is telling the truth. The map is also completely irrelevant to the problem.

Working the diagnostic backwards

NanoVNA on the antenna first, as always — right around 1.3 SWR on the FT8 portion of 20 meters, resistance in the high 30s, reactance essentially zero. Antenna and match, cleared. I didn't think to photograph that first sweep, but I ran it again later and it reads the same.

Then the S-meter test: S5 with the antenna connected, S1 with it disconnected. That's roughly 24 dB of noise arriving through the antenna system, not generated inside the radio. So I started killing things one at a time. Disconnecting Starlink dropped about half an S unit. Shutting the engine off dropped another half. That left me at about S4 antenna-connected against S1 disconnected.

That last measurement redirected the whole morning. S4 against S1 on 20 meters in daylight is normal external band noise — I was externally noise limited, which is the healthy condition. There was nothing left out there to chase. Which meant the problem was downstream of the antenna, in the audio chain.

The actual culprit

I looked at the WSJT-X input level. It was sitting at 87 dB. I watched it settle to 74. It should be somewhere around 30.

That's a badly overdriven sound card, and the failure mode is specific and vicious: strong stations clip, and the clipping products smear across the passband and bury everything weak. You don't get an obviously broken receiver. You get one that decodes the loud stuff just fine and silently throws away every marginal signal on the band. It looks like propagation. It looks like a bad antenna. It is neither.

The X6200's line out gain adjustment only has coarse detents — 0 lands around 10 dB, and rolling it to about 1:00 jumps you to 70 or 80. There's no useful middle. So the fine adjustment had to happen on the Pi side: alsamixer, Tab over to Capture view, Mic capture slider from 64 down to 27, then alsactl store to make it survive a reboot.

That brought the meter to a baseline around 25 to 30 with peaks to 47 on strong signals. Weakest decode went from −17 to −23 — FT8's theoretical floor is about −24 — and decodes settled in at around seven per cycle. The band activity window filled with stations that had been there the entire time.

On the air

First call in the log was HI3A in the Dominican Republic at 7:59 AM — worked from the lot next door, a minute before the gate opened, at 917 miles. They gave me a +08, which tells you the outbound side was never in question.

Then the gate opened, I packed up, moved onto the property, and set back up. Every remaining contact came from inside the park. VA3TS in Ontario, VE2FVV up in Québec, W9DRC, N7MDW right here in EL87, and VE3GLN in Ottawa — who handed me a −03. W0RW out in Colorado, WA3RFE in Virginia, AA5HH in east Texas, and KJ6HNP closed it out at 10:40 AM for number ten.

Ten QSOs, ten unique callsigns, all of it on 20 meter FT8 at five watts. Exactly the number POTA needs, which is a satisfying place to land after starting the morning locked out of a park and deaf on the air.

The noise came back

Later in the activation the floor jumped to S6 and the decodes fell off a cliff. My first instinct was space weather, but the K index was quiet, so that wasn't it. What had actually happened: I'd turned the engine on for AC, and starting the engine had also brought Starlink back up. Both noise sources I'd carefully eliminated, restored in one thoughtless move.

Shutting them back down brought the floor back. Annoying in the moment, but it confirmed the earlier measurement — the vehicle's electrical system and Starlink together account for roughly 6 dB on 20 meters. That's not a guess anymore, that's a number I've measured twice.

Still on the list: a Mix 31 common-mode choke at the feedpoint, ferrites on the Starlink DC lead, and braid bonding straps across the hatch hinges to the chassis. None of that would have fixed this morning's problem, but 6 dB is 6 dB and I'd like it back.

The lesson worth keeping

A flat SWR and a beautiful PSK Reporter map tell you nothing about your receive path. They're both measurements of your transmitter. Check the WSJT-X input level early — make it part of the setup routine, right after the SWR check. An overdriven sound card will quietly cost you every weak signal on the band, and it will do it without ever looking like a fault.

Would I activate here again?

YES — with one asterisk, and it's the one I put on myself. The gate is real and it does not open until 8. Show up before that and you're operating from the lot next door, which works fine, but it isn't why you drove out here. Get there after eight and it's a good site: open lawn, mature oaks, room to park and set up without being in anybody's way, and a mansion worth walking around between cycles. The parakeets are free.

73 de W4GGJ

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Activation Stats

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All-Time POTA Stats

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Gear used in this activation: Xiegu X6200 · Harvest OUTB2000 HF/6M · NanoVNA · LiFePO4 Battery · DigiPi on RPi 4

Tags

20 meters 20m alsamixer amateur radio audio levels DigiPi Digital Ellenton field operations Florida FT8 Gamble Plantation Historic State Park ham radio Harvest OUTB2000 Manatee County NanoVNA noise floor Parks on the Air portable HF POTA QRP receive troubleshooting Starlink TavaOne Activate US-3625 W4GGJ WSJT-X Xiegu X6200

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