After making several improvements to the antenna’s counterpoise system and portable setup, I finally had the opportunity to evaluate the Yaesu ATAS-120A under real-world WSPR operating conditions.
The primary goal of this outing was to compare the antenna’s performance on the 10 m, 12 m, 15 m, and 17 m amateur bands. I also planned to continue with 20 m and, finally, perform a series of experiments on 40 m using a newly designed counterpoise system specifically developed for that band.
Test Conditions
The test was carried out from grid locator JO70FB (Prague, Czech Republic).
Unfortunately, the weather was far from ideal. Heavy rain showers and thunderstorms moved through the area during the test, forcing me to keep the operating session much shorter than originally planned.
Despite these conditions, I was still able to collect enough data to evaluate the higher HF bands.
Results
Considering both the weather and the limited operating time, I was pleasantly surprised by the overall performance of the antenna.
The 10 m, 12 m, 15 m, and 17 m bands all produced very encouraging results. WSPR spots were received from stations across Europe, along with several long-distance DX receptions, confirming that the ATAS-120A performs remarkably well in a portable configuration.
The detailed results for each band, including the Top 10 DX receptions, are presented in the following sections.
10 m (28 MHz)
Top 10 Longest-Distance Receptions
| # | Callsign | Country | Grid Locator | SNR | Distance |
|---|---|---|---|---|---|
| 1 | EA8/DF4UE | Canary Islands | IL38BP | −21 dB | 3,368 km |
| 2 | 4X1DA | Israel | KM71LV | −23 dB | 2,641 km |
| 3 | RX6ART | Russia | KN95RL | −14 dB | 1,926 km |
| 4 | EA1FAQ | Spain | IN71PN | −18 dB | 1,753 km |
| 5 | EA5XQ | Spain | IM99 | −20 dB | 1,691 km |
| 6 | SM2KOT | Sweden | JP95HB | −16 dB | 1,685 km |
| 7 | SWLIO53PS | England | IO53PS | −21 dB | 1,633 km |
| 8 | SV1BTL | Greece | KM18VA | −17 dB | 1,530 km |
| 9 | OH6BG | Finland | KP03QA | −13 dB | 1,500 km |
| 10 | GM4WJA | Scotland | IO87MN | −2 dB | 1,409 km |
Top 5 Strongest Reception Reports
| # | Callsign | Country | SNR |
|---|---|---|---|
| 1 | ON5KQ | Belgium | +20 dB |
| 2 | ON5HB | Belgium | +11 dB |
| 3 | LX1LC | Luxembourg | +10 dB |
| 4 | G8OCV/SDR | England | +10 dB |
| 5 | PE0MJX | Netherlands | +9 dB |
Summary
Total Number of WSPR Spots: 162
Transmit Power: 5 W
Longest DX: EA8/DF4UE (Canary Islands) – 3,368 km
Best Reception Report: +20 dB from ON5KQ (Belgium)
12 m (24 MHz)
Top 10 Longest-Distance Receptions
| # | Callsign | Country | Grid Locator | SNR | Distance |
|---|---|---|---|---|---|
| 1 | EA8/DF4UE | Canary Islands | IL38BP | −25 dB | 3,368 km |
| 2 | EA1FAQ | Spain | IN71PN | −23 dB | 1,753 km |
| 3 | EI4HQ | Ireland | IO51UU | −18 dB | 1,599 km |
| 4 | SV1BTL | Greece | KM18VA | −15 dB | 1,530 km |
| 5 | OH6BG | Finland | KP03QA | +1 dB | 1,500 km |
| 6 | M9PSY | Northern Ireland | IO86HA | −18 dB | 1,358 km |
| 7 | M9PSY-1 | Northern Ireland | IO86HA | −23 dB | 1,358 km |
| 8 | M9PSY-2 | Northern Ireland | IO86HA | −17 dB | 1,358 km |
| 9 | EA3IQK | Spain | JN11BJ | −12 dB | 1,355 km |
| 10 | GM4DTH | Scotland | IO85JW | −17 dB | 1,345 km |
Top 5 Strongest Reception Reports
| # | Callsign | Country | SNR |
|---|---|---|---|
| 1 | HB9VQQ | Switzerland | +18 dB |
| 2 | HB9VQQ/RS | Switzerland | +18 dB |
| 3 | DARCT13 | Germany | +17 dB |
| 4 | HB9VQQ/RE | Switzerland | +17 dB |
| 5 | HB9VQQ/RL | Switzerland | +13 dB |
Summary
Transmit Power: 5 W
Total WSPR Spots: 118
Longest DX: EA8/DF4UE (Canary Islands) – 3,368 km
Best Reception Report: +18 dB from HB9VQQ (Switzerland)
Coverage: Excellent propagation across Europe, with the longest reception reaching the Canary Islands.
15 m (21 MHz)
Top 10 Longest-Distance Receptions
| # | Callsign | Country | Grid Locator | SNR | Distance |
|---|---|---|---|---|---|
| 1 | V51RS | Namibia | JG87QL | −28 dB | 8,076 km |
| 2 | VE6JY | Canada | DO33OR | −22 dB | 7,467 km |
| 3 | WD4ELG | USA | FM06BE | −21 dB | 7,291 km |
| 4 | WA2TP | USA | FN30LU | −23 dB | 6,503 km |
| 5 | KQ2Y | USA | FN31GN | −22 dB | 6,478 km |
| 6 | EA8BFK | Canary Islands | IL38BO | −24 dB | 3,372 km |
| 7 | EA8/DF4UE | Canary Islands | IL38BP | −20 dB | 3,368 km |
| 8 | EA1FAQ | Spain | IN71PN | −14 dB | 1,753 km |
| 9 | EA5XQ | Spain | IM99 | −22 dB | 1,691 km |
| 10 | SM2LTA | Sweden | JP94AT | −21 dB | 1,653 km |
Top 5 Strongest Reception Reports
| # | Callsign | Country | SNR |
|---|---|---|---|
| 1 | HB9VQQ | Switzerland | +27 dB |
| 2 | HB9GZW | Switzerland | +17 dB |
| 3 | DK6UG | Germany | +17 dB |
| 4 | IW3HBX | Italy | +8 dB |
| 5 | DARCT13 | Germany | +6 dB |
Summary
Transmit Power: 5 W
Total WSPR Spots: 281
Longest DX: V51RS (Namibia) – 8,076 km
Best Reception Report: +27 dB from HB9VQQ (Switzerland)
Coverage: Outstanding propagation across Europe, North America, the Canary Islands, and Africa, with the longest reception reaching Namibia.
17 m (18 MHz)
Top 10 Longest-Distance Receptions
| # | Callsign | Country | Grid Locator | SNR | Distance |
|---|---|---|---|---|---|
| 1 | V51RS | Namibia | JG87QL | −23 dB | 8,076 km |
| 2 | VE6JY | Canada | DO33OR | −21 dB | 7,467 km |
| 3 | N4MXZ | USA | FM17FK | −29 dB | 7,046 km |
| 4 | KD2OM | USA | FN12GX | −25 dB | 6,620 km |
| 5 | WA2TP | USA | FN30LU | −24 dB | 6,503 km |
| 6 | KQ2Y | USA | FN31GN | −22 dB | 6,478 km |
| 7 | VY0ERC | Canada (Nunavut) | ER60TB | −19 dB | 4,753 km |
| 8 | HZ1SF | Saudi Arabia | LL34HQ | −28 dB | 3,949 km |
| 9 | 7Z1DH | Saudi Arabia | LL24FN | −17 dB | 3,834 km |
| 10 | EA8/DF4UE | Canary Islands | IL38BP | −23 dB | 3,368 km |
Top 5 Strongest Reception Reports (Unique Stations)
| # | Callsign | Country | SNR |
|---|---|---|---|
| 1 | PA0LSB | Netherlands | +17 dB |
| 2 | DD5XX | Germany | +15 dB |
| 3 | IW3HBX | Italy | +15 dB |
| 4 | ON5KQ | Belgium | +15 dB |
| 5 | DK6UG | Germany | +12 dB |
Summary
Transmit Power: 5 W
Total WSPR Spots: 457
Longest DX: V51RS (Namibia) – 8,076 km
Best Reception Report: +17 dB from PA0LSB (Netherlands)
Coverage: Excellent propagation extending across Europe, North America, the Middle East, the Canary Islands, and Africa, with the longest reception reaching Namibia.
An Unexpected Technical Issue
When I switched to 20 meters, an unexpected problem prevented me from continuing the test.
During transmission, both JTDX and WSJT-X repeatedly reported an „Unable to read audio input“ error, causing the software to stop decoding. Restarting the applications—and even the computer—temporarily solved the issue, but it returned after some time.
At the moment, I suspect that RF energy is coupling into the DigiRig Mobile USB interface, particularly on the lower HF bands.
For my next field test, I plan to:
- replace the current USB cable with a higher-quality shielded cable,
- install ferrite common-mode chokes on the USB cable,
- add additional ferrites to the remaining interconnecting cables if necessary.
Only after solving this issue will I be able to complete the planned testing on the 20-meter band.
40-Meter Counterpoise Experiments
Because the weather deteriorated rapidly, I unfortunately had to cancel the part of the test I had been looking forward to the most—the 40-meter counterpoise experiments.
For this band, I have designed a new counterpoise configuration using longer radials specifically optimized for 40 meters. Based on earlier measurements, I expect this setup to provide a noticeable improvement compared to my previous portable configuration.
These experiments will therefore have to wait until my next portable outing.
Conclusion
Despite the poor weather and the unexpected technical issues, I consider this field test a success.
The results clearly demonstrate that the Yaesu ATAS-120A, when combined with a properly designed counterpoise system, is capable of delivering excellent performance in portable WSPR operation.
Over the coming days, I will continue updating this article with detailed results for each band, including Top 10 DX stations, propagation maps, and additional observations from future field tests.
OK1TK HAM Radio 