But this time I thought I would share the build and decided to post the step by step instructions here at ham radio operator blogspot and planet ham.
12mm aluminium box section tube. (boom)
50 ohm feeder/coaxial cable. (2 lengths for dual bands)
Sponge foam and insulation/sticky tape. (handle)
Step 1) The IOIo paperwork. I made the elements from 2.4mm diameter T.I.G welding wire which worked out at:
145 mhz reflecting element( I )= 1004mm.
145 mhz loop element ( O) total length = 2058mm.
435 mhz reflecting element ( I )= 337mm.
435 mhz loop element (0) total length = 642mm.
The spacing of each element from back to front =
152mm, - 324mm, - 100mm, - 51mm & - 108mm.
(visible on the drawing , click to enlarge).
Step 2) I don't like wasting materials so I joined two short scrap pieces of tube together by filing some 12mm round bar into a square interference type fitting.
Once filed up I was able to tap the squared round bar into the ally tube to join the boom.
Once mated up it gave a total length of 1000mm (1M)
Step 3) Using some 3mm plastic sheet I drew a desired shape and cut the plastic using a hand shear otherwise known as a bench knife. The sheet at this stage is used to insulate and mount the elements to the boom. Also mark the element spacings using a marker pen on the boom.
Step 4) drill 6 holes that will allow the cable ties to hold the elements as well as clamp the insulated mounts to the boom. I drilled the centre of the plastic so I could see the previously pen marked position of each mount easily on the ally boom. Just one more to go giving a grand total of 6 plastic insulated mounts.
Step 5) Here you can see the central holes showing the spacing pen marks of the boom. Once lined up, pilot drill the boom and attach the plastic mounts/insulators using self tapping screws.
Step 6) Time to solder the 50 ohms coaxial feeders to both loops, then cable tie (tie rap) the elements to the fitted insulator mounts.
A close up of the 435mhz Loop and reflecting element cable tied and soldered up.
Repeat the technique for the 145mhz side of the antenna and use a separate 50 ohms feeder. Once this stage is complete the IOIo starts to take shape and just needs the elements fixing firmly.
Stage 7) I cut a 50mm x 1000mm strip of plastic, aligned the elements and using more self tapping screws I was able to clamp down the elements. This stiffened up the antenna and prevented the elements from moving out of line. The antenna is now ready to solder the plugs on to connect to your desired radio. I used 2 PL259 plugs.
Here is a closer look at the bottom side of the finished mk 6 IOIo antenna. (the front end 435 mhz )
The full picture showing the bottom side of the finished antenna.
The view here shows the complete antenna from the top side.
Here is a close up of the finished project.
I tried it using my old Yaesu FT-470 and was very pleased when I opened up a repeater 25 miles away +60 db on 145mhz. It worked well also on 433mhz providing me with instant and easy access into the local 70cms repeater. (not bad to say its resonant on 435mhz and I was inside my qth using less than 5 watts.) I will try it on a satellite over the next few days.
So once again I was pleased with my antenna tinkering and this model was much lighter so I shouldn't get too much arm ache when I am out playing.
I hope some more of you have a go at making one. Thanks to all of you again for telling me about your personal experiences in building Satellite antenna's for Amateur Radio. I look forward to hearing more about your projects and I hope to hear you coming through loud and clear via the "birds". Good luck and best 73