Here is the latest piece of the 6 meter yagi antenna I’m designing / building. Since my plan is to use a hairpin match, the driven element needs to be isolated from the boom. I used ABS 1″ diameter plastic rod, and epoxied 1/2″ diameter x 1″ long pieces of aluminum rod, which had already been drilled and tapped for 1/4-20 whips. The notch had to be deeper to match the offset on my reflector and driven element mounts, as shown.
Tonight I mocked up the new antenna. I am using some leftover parts for the tripod/mast. I turned a simple bushing to mount the mast to the tripod. The antenna is about 16′ high on this mast. The driven element is not finished yet. I picked up some 1″ ABS round on Friday, and will make the 1/4-20 mounts with that plastic to isolate it from the boom.
I have the upper 2 sections of a telescoping mast left over from another project, and a new surplus Bogen tripod. To fit the mast sections to my tripod, and had to turn a bushing adapter. Tonight I finished that part and tested the fit.
I will guy this setup when there is an antenna mounted. I’m hoping it will be sturdy enough to support my 10′ 6 meter yagi and my Arrow 4 element yagi at the same time.
Getting ready for field day 2013, I decided to build my own 6m 4 element Yagi antenna. My goal is to have something that’s portable, with a bit of directional gain. If it turns out light enough, it could be useful for some of the easier SOTA activations and maybe the Colorado 14er event.
I am modeling this antenna after the Buddipole antenna system. I would have just purchased those parts, but they do add up fast, and I have my own machine shop!
Counter-sink tool
My Jet BD1331 lathe
Partially finished parts
3/4″ end mill
With Buddipole featherweight whips installed and extended
Close-up of whips installed in rotating collars. 1/4″-20 threads
Installation of a NMO mount in a Honda Element:
Removing the upper console. Pry out the 2 light covers, then use an 8mm nut driver to remove the bolts.
The A pillar trim pops off without any tools. The coax can be tied to the wire bundle behind the panel.
Lay a tape measure on the roof. Line up the end of the tape with the black edge of windshield. This could vary depending on your windshield. On mine I measured 9″ from this point for my 3/4″ hole, made with a step drill.
Here is a larsen 2/70 antenna installed. I am going to order something shorter that will clear the garage door.
In looking around for a decent battery for SOTA activations on my FT-817ND radio, I decided that nobody was making the exact battery that I wanted. Up until now, I’ve been successfully using a Bescor 4500mAh, 12V NiMH battery. I wanted something that was slightly lighter, and also a lower pack voltage to minimize the standby current on this particular radio.
I decided on the LiFePO4 (Lithium Iron Phosphate) technology, because it has a lot of the energy characteristics of other Lithium batteries, but with less chance of fire! All my parts were purchased from BatterySpace.com. They shipped pretty quickly and I got exactly what I ordered.
Here are the parts as they arrived in the mail. (3) 3300 mAh cells, a fusible link, an over temperature link, some heat shrink and a balancing connector.
A shot of the individual cell:
The over-temperature link. I connected this between cells 2 and 3.
Here’s a shot of the self-resetting fuse. This was soldered between cell 1 and 2:
Before I soldered any of the cells, I hot glued them together. I always used to think hot glue guns were for craft folks. I now find myself using it a lot for fabricating “stuff.”
After shrink tape applied! I put 2 wraps on and alternated them. Once it’s fully tested I’ll put 1 more wrap on just to be safe.
Here’s the pack connected to the balancing board on my Thunder Power TP610C-ACDC charger. I got this charger a few weeks ago, and it’s the fanciest battery charger I’ve ever had! I’m glad I spent the money on something nice and versatile. I’ve used it for my SLABs, AGMs, NiMH packs and now the LiFePO4 pack.
View of the charger. This one is nice because it can use DC or AC as a source of power for charging. Handy if you’re at home or in the field.
View of the screen with first charge. The little carrot indicates that the charger is sensing the center taps between cells. BTW, on the balancing wires, connect the red wire to red, black to black. The Green wire, which is adjacent to the red wire on the balancing plug, should connect to the tap between cell 2 and 3. The yellow wire which is next to the black wire, should connect to the tap between cells 1 and 2. To test, measure on the balancing connector. Between black and Yellow, you should measure 1 cells voltage (~ 3.5V). Between black and Green you should measure 2 cells in series, or ~ 7.0VDC. Between black and red, you should have the full pack voltage of ~ 9-10VDC. The cell voltages will depend on the state of charge that the batteries arrived in.
Keep an eye on this battery during the first few charge/discharge cycles. It should be perfectly safe, but it’s better to keep an eye on things.
Made my first 2m ssb contact tonight from Fort Collins to Eaton on 5W using my FT-817nd and Arrow 146-4BP. Fun!
I have a 12v / 4500mAh battery that I’ve been using with my FT-817nd. It is NiMH technology and is lighter than a comparable SLA battery. The problem has been charging, since I only had a SLA charger. Today I picked up a Thunder Power TP610C-ACDC charger from Hobbytown that can charge LiPo, LiFePO4 (and other lithium types), NiMH, NiCad, Lead acid and maybe others. It has some really nice features. I’m planning to also put together a Li-ion pack using surplus camera batteries, so I wanted a versatile charger.
http://4wdx.com/
Banjo Hangout