*************************************************************************** * ATGP 2018 Report for Hawksbill 75 *************************************************************************** Shawn, N3AE and Detrick, K4IZ, arrived at the Upper Hawksbill parking area at 08:30. Detrick was a last minute fill-in for Eric, WG3K, who was dealing with a family emergency. Detrick's help was MUCH appreciated. We had some light drizzle on the way up to Hawksbill peak. Advance photo recon using pictures on the web suggested a novel way to anchor N3AE's fiberglass mast at the observation area. The area is surrounded by a stone wall. But at one point there is a 2" drain extending through the wall at its base. We put a long bungee through the pipe, grabbed the other end and basically made a vertical bungee band around the stone wall. The fiberglass mast was lashed to the bungee with some cable ties. This worked very well, even with the wind we experiences at the summit. Our antenna was a home brew roll up J-pole suspended on top of the 15 ft mast. Rig was a Kenwood D700 pre-configured for the GP event by WG3K. Power was a 25AH LiFePO4 battery. No laptop. We got on the air at about 10:00 and quickly copied beacons from MDMTN to the north. AOMTN came up a bit later, but there were issues between AOMTN and Hawksbill. More on that later. Our weather turned from light drizzle to more of a mist and fog as we were "in the clouds." Over the course of the event, the clouds briefly opened up several times for a great view of the valley below. Hawksbill Mountain is the highest point in Shenandoah National Park and as such has numerous hikers coming up regardless of the weather. We were always asked about what we were doing. Guesses ranged from the correct answer, amateur radio, to conducting some kind of weather research. I think the GP event provided more of an opportunity to discuss and present amateur radio than any field day event I have ever participated in. Mid event we were visited by Eric, W4EON, and his grandson. Regarding the challenges between AOMTN and Hawksbill... AOMTN reported that they could hear us but rarely were able to decode our packets. MDMTN to the north had no issues hearing us and decoding our beacons. We never had problems hearing and decoding AOMTN. AOMTN reported no problems hearing and decoding beacons to their south. So the issue was just AOMTN decoding Hawksbill. We tried changing power level to see if RF feedback was the culprit but that made no difference. We briefly changed frequency to 144.39 and launched a beacon or two. Detrick used his smart phone to access aprs.fi and there we were. Good decoded packets received by at least three stations. After coodinating with WG3K, John at AOMTN relocated their antenna. This had the positive effect of significantly increasing our received signal strength at AOMTN but they still issues decoding our packets. Other tests followed, such as us changing frequency 5 KHz up and 5 KHz down thinking there might be an oscillator error in the D700. AOMTN did't hear us when off-frequency so that was not the issue. My personal theory is that a strong and persistent multipath exists between Hawksbill and AOMTN, causing enough received symbol overlap at AOMTN to make good packet decodes difficult. Around 1500, both we and AOMTN switched to 9600 baud briefly and SUCCESS. They heard and decoded our beacons and we heard and decoded theirs without problems. This might support the multipath theory since signal timing changes with the different baud rates. Or the Kenwood D7xx series is better dealing with 9600 baud. Over to the experts to think about this further. Shortly after 1500 we secured our operation and hiked down to the parking area, followed by a difficult drive home due to the pouring rain to the east. Other lessons learned...it would sure have been nice to have a small laptop to monitor the packet traffic. Maintaining situational awareness using only the D700's front panel display is not very effective. Shawn - N3AE