Upgrades and Tweaks for the QRP Portable station
March 15, 2015
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I made a few minor changes to the portable QRP station based on the Yaesu FT-817ND. First I upgraded the solar panel to a foldable 60W panel. It spreads out like a tarp on the ground or hangs over a chair. Added some power poles to this for quick and easy changes to the configuration. Also added a second wattmeter for the load side. Now I can monitor what is coming out of the solar panel and what is going to the load. Also swapped out the solar charge controller for a slightly fancier one. It was billed as a MPT controller but looks like it is a PWM controller with an LCD display. The display is nice as it shows what each component is doing.
I operated in overcast skies this afternoon for about 2 and a half hours and made seven contacts. The wattmeter from the solar panel showed .295Ah during that time while on the load side I consumed 1.057Ah. I am sure that on a sunny day the panel would have kept the battery fully topped off.
The Yaesu FT-817ND shows a current draw of 330mA on receive and 1.68A peak during transmit. So the go-box is pretty well set. Just need to get a cheap multi-tool to throw in there as you never know when something will need adjustment.
The big tweak today came with the homebrew Buddistick. I did some EZNEC modeling and found out some interesting things. The main two observations were that I needed to get the feed point higher to at least 8 feet (from the 5 and a half feet I tried last time) and replace the wire in the two foot PVC segment with Aluminum tubing. Both of these result in much better predicted gain and low angle radiation. So off I went to Lowes for a 3/4″ Aluminum tube. It was pretty straight forward to cut it to length with a hacksaw and drill two holes at the same place in the PVC pipe where the wires came out of. The tube fits inside the existing piece of 3/4″ PVC pipe.A screw on each end holds the pipe in place and serves to connect the wires to the rest of the antenna.
Lastly I had to cut longer pieces of paracord for the guy wires. Straight forward enough, I simply divided a 50ft length into three equal pieces. Setup takes about 15 minutes in my backyard. The antenna tuned up easily using the Mini60 analyzer to about 1.4 SWR on 10m. So…put on my headphones and…the results?
First two contacts were in Idaho for the Idaho QSO party both were 59. Did a bit of tuning and picked up a CQ from New Zealand. He returned my call and I had a 33 signal report! Next was a 57 in Chile. Then picked up a lonely CQ from Japan who reported me at 53. This was followed by a 52 from Argentina and finally a 53 from Japan. The last contact was 7421 miles from my QTH. This worked out to 1484 miles per watt at 5w!
The changes I made seemed to work successfully and this on a day with SFI of 119, SN of 56 and poor predicted band conditions on 10m.
All in all a nice afternoon outdoors working DX on QRP!