Jul 182010
 

Well, I’ve been riding a lot between West End and The Gap, and I get a lot of questions from people on the band about my setup. I was doing some repairs… one of the wires to the PTT had disconnected, luckily there was a 0V return via other connections… and so while I had the bike outside fixing that (it was too dark in the garage) I took the opportunity to snap some photos.

The light was fading at the time, so the pictures aren’t particularly great… I’ve touched them up to make them brighter, hence there’s a bit of noise in the photo… The last two showing the HF setup, required a flash (which I was trying to avoid due to the aluminum and reflectors)… and of course I didn’t spend time putting the FT-897D in the back… maybe later when I get everything tuned up and actually do make a true bicycle-mobile contact on HF (this one was not made mobile).

VK4MSL/BM on 2m

VK4MSL/BM on 2m: side view

Above, is the station in its entirety… fairly simple. The antenna is a plain 2m ground-plane, formed using a tunable mobile whip cut for 145.700MHz, the aluminum angle bracket makes up one counterpoise, and an additional counterpoise hangs out the back. Adjusting the angle has an influence on the SWR… in this arrangement, it works nicely.

VK4MSL/BM: Closeup of rear basket

VK4MSL/BM: Closeup of rear basket

Shown here is the rear basket where the FT-290R II (or FT-897D for HF) lurks… along with a 9Ah gel cell battery, which also powers the tail light. I haven’t been very neat about the cables. Two leads run from the front controls, the grey one (shielded) carries transmit/receive audio and the PTT, the blue one (Cat5e UTP) carries the four directional buttons — with spare wires connected to 0V. A DB15HD (“VGA”) connector terminates the cable at each end.

VK4MSL/BM: Radio controls

VK4MSL/BM: Radio controls

Remember how I mentioned the hand-mic in the last station was going to be temporary? Well… this is the arrangement here. Shown here is the PTT switch (red) and four directional buttons. Not all radios make use of all buttons … the FT-290R II uses only the up/down buttons, the FT-897D uses the right-hand button in addition for the “fast” button. Homebrew microcontroller-based radios I build will probably use all five shown for a menu interface. There’s no display in front of me, so don’t ask for an accurate signal report, I can tell you whether it’s a Q3 or a Q5, but any S-meter reading will be a wild guess. Future expansion of this may include a small potentiometer for a local volume control, and a small microcontroller-driven LCD that could be used to interface to the FT-897D’s CAT interface… but this is just early days.

Now… I did say I managed to mount a HF antenna on here and make a contact with it. The contact into VK5 that yielded this QSL card was made using a 6′ long CB whip… the station looked a lot like this:

VK4MSL/BM: HF Antenna

VK4MSL/BM: HF Antenna

The flash was needed here, took me a while to figure out where I had put the bracket (I don’t plan to ride with the HF antenna or bracket mounted very often). This is fortuitous in a way since you can now more visibly see the 2m antenna. The CB antenna mounts on a nearly identical bracket. I don’t bother with the radial out the back, as there’s no way I’ll make one long enough that would be practical. The antenna will need some work, in particular, either addition of a base-load coil, or modification, to make it resonant on the amateur bands.

VK4MSL/BM: Closeup of basket with HF mount

VK4MSL/BM: Closeup of basket with HF mount

With a small base-load coil, I should be able to make it a half-wave end-fed on 6m… some more and I should be able to make an end-fed quarter-wave on 10m. This will be the subject of future experiments. This tuning section will probably mount on top of the mounting itself, underneath the spring shown on the right.

And to answer the number one question I get from non-radio amateurs… no… I do not have a camera on my helmet (this is not a camera)… I am not broadcasting video. Kindly don’ t act like someone excited to be on television… you’re not. 😉