开云体育

Here's a brief write up on Greg Mihran's presentation (attached). Many POTA enthusiasts describe the POTA PERformer as a game changer. What struck me about Greg's work is his attention to both antenna modeling and field measurement. For example many amateurs have been told that ground plane radials should be 1/4 wavelength long but by measuring the current flow on the radials he was able determine this is not optimal. Proximity to the ground detunes the radials lowering their resonant frequency so the point of maximum current is pulled away from the base of the vertical into the ground increasing losses. Another novel concept is measuring how counterpoise length can affect the resonance of an end fed half wave. Most of us have been told the outer shield of the coax can serve as the counterpoise and the length doesn't matter but that's not necessarily optimal. When I'm operating portable I want the most efficient antenna system I can transport and setup easily. Bring your antenna questions and enjoy! 73, Peter K1AV

Hello BVARC, I will be operating portable from Aruba through April 9th and had a brief contact with K1ETA Tuesday evening. I'll be looking to make contact with the crew at the Bellingham library Saturday morning and activating Arikok National Park (AW-01) Sunday afternoon (on 15 and 20m CW). Feel free to email me if you want to schedule a QSO (psichel@...). I missed the club meeting Monday and would like to invite any who are interested to join the Field Day committee for the coming June event. I’ll be hosting our first planning meeting via Zoom on Monday April 21st from 7-7:30pm. Will email details after I return. 73, Peter P4/K1AV Antenna is a 25' Rybakov (3/8th wave) vertical support by a 10m fiberglass mast.

The Bellingham Library Event on April 6th is listed in the calendar section of the Valley Breeze. 73 Matt NA1Q

Well I was looking into POTA this summer, and wanted a rather minimal setup. I know I like doing FT8 and was looking at my options, the IC-7300 with a tablet, laptop, or cellphone. Then I looked at yhe QRPLabs QDX and QMX transceivers, but I still would need the laptop, tablet or cellphone. Then I ran across WB2CBA and W5BAA's DXFT8 QRP transceiver. This is a you have to build it from components and program it with firmware. So you order the RF board kit from Kees Talen K5BCQ via a paypal payment of $45.00, the STM32f746 Discovery Board from Digikey, a Micro SD card 8GB or larger, a CR2032 button cell for the real time clock, and a Mini USB cable for programming. Once everything arrived, I spent 2 hours using a very slow laptop installing the firmware in the STM32 and setting up the MicroSd card info file. I then spent another 4 hours soldering and assembling the radio. And once hooked up I had transmit but no receive. So I did a couple quick tests listed in the Groups Io DXFT8 board and discovered U1 a SMD IC was only half installed, like it shifted in the solding process, so I slid it back so all 4 tabs made contact with the board and that solved the problem. So I hooked it up to the antenna and powered it up, and it was now receiving. Unfortunately it is a QRPp transceiver which max power out on 40m is only 840 mW, on 10m its around 520 mW. Not bad for running off a 5V 1a USB Cellphone charger. You can power it with a 9 yo 15v external power source but it's only going to give less than 1 watt of RF. Plus side is it will run off one of those cellphone USB battery packs and the radio is about 1-1/8" thick and the same size as my cellphone with 3 times the weight. Now just need to add a SMA antenna and I'll be all set for POTA this year. 73 Matt NA1Q