G4HFQ software is quite good. The FTBasicMMO handles memory management ($18.50).

http://www.g4hfq.co.uk/

- Tim (KA1OS)

Beware: I've seen couplers that pass the lines straight-through and others that 'invert' the connnection order.

Measure (continuity) twice, splice once.

" Most ducks aren't close to 2M. The ones that are keep handy, ..."

I didn't think that testing them on an analyzer would tell you what their impedance will be on an HT. Furthermore, having a perfectly matched impedance doesn't necessarily indicate which antenna will operate best. The HT and the operator are all components of the antenna system. That 'system' is very hard to analyze. It's easier to work with a buddy to try out each duckie in sequence.

I found a local ACE Hardware shop with 6' aluminum tubing. These were sized so that you could telescope a few. They wanted about $8-$11 per tube.

I've never seen similar aluminum tubing at Home Despot or bLowes.

- Tim

Yes, you can get around having to use the programming box by entering the data by hand...

OK. G4ZLP sells a line of radio interfaces and his products are of good quality and low price - find him on Ebay. You can also make an interface but the net savings will be small. Google around a bit to find a circuit design.

I believe that the FT-8500 was one of the few VHF/UHF FM radios which could be directly controlled via a serial connection (as opposed to just cloning or programming memories). I always thought that feature was pretty neat (even with the potato microphone). If you ever get bored with the radio, drop me a line.

- Tim

Hmm... Looking deeper it seems that another designation for the 6-pin plug is RJ25. The key is that you want the full set of six connections brought out, not just the 4-pins more commonly found with residential phone plugs. The RJ25s can be found at most Radio Shacks.

Yes, you can cut the cables. If you're interested in the pinouts, you can Google "FT-857 Service Manual", but given that you already have the cables in hand, it should be simple enough to determine the connections with a DVM. The control head uses a 6-connector plug (RJ12) while the microphone connector is terminated with an 8-pin, RJ45 plug. These are simple to attach with a crimper.

When purchasing the plugs, try to get ones that are appropriate for the type of wire (probably stranded) and cable (round vs. flat).

See also:
http://www.eham.net/forums/Articles/81249

Good luck,
Tim

It all depends on what you want to do and how you plan to operate. VHF/UHF rigs are cheaper, easier to install and less affected by the auto's electrical noise. For your first mobile installation they are easier to get right. Of course your range is often limited by available repeaters on those bands.

Learning to operate on HF in a mobile environment would not be my first choice for beginners. I think you're likely to have a lot more success starting in a home or base-camp setting with a wire dipole. If you want to hedge your bets, consider one of the smaller V/U/HF rigs that could be installed in an auto when the time comes.

If cost is an issue, another idea is to install an V/U/HF rig in the auto in such a way that you can readily remove it for double-duty (Use a secure mount in any case). Operate the rig in the car for V/UHF and in your shack for HF. Wire antennas are cheap; multiband, mobile HF whips can be pricey.

As for buyer's remorse with the 706mkIIG: Buy one used and sell it when you want another rig. You won't take too much of a loss.

WA8LMF's site referenced above is definitely worth examining. I'm planning to mount my 2m/70cm antenna similarly. As John mentions, the site has plans for a mount depicted in a .pdf file. I'm trying to find a nearby machinist that I can bribe with a six-pack to fabricate a couple of these mounts.

John, you wrote a note that Bruce Perens (K6BP) posted on his web pages (http://perens.com/works/hobbies/ham/prius/rfi/). Would you like to comment further? It sounds like you're investigating how to choke the noise on the 12V lines.

Also, about hatchback mounts, the ones secured to the edges around the top or upper side of the hatch: I've discussed this with other Prius-owning hams. There is some concern about bending the top lip of the hatch if the antenna gets a good 'thwack!' or some kid gives the antenna a strong tug.

Regards, Tim (KA1OS)

Here's a supplier in Australia:
http://www.raedale.com.au/DTMF.htm

And Far Circuits sells PC boards for making your own:
http://www.farcircuits.net/dtmf1.htm

Before considering the latter option, note that most of the old chip-based, dedicated DTMF encoders are discontinued.

Assume nothing about a black box...
"I suspect everyone and I suspect no one."
- Inspector Clouseau, from 'A Shot in the Dark' (1964)

Short of reading the service manual and examining the circuit diagram, it's hard to say anything definitively but you can check the voltages on the lines. See if there is DC voltage across pins 1 (mic) & 6 (gnd). If there is, you may be able to get away with plugging the two pins from the microphone straight into those lines. If there isn't any DC, you'll probably have to add a resistor (to 5V) and a capacitor (in series to the mic input) into whatever adapter you eventually construct.

Assume nothing about a 3-pin microphone as well, unless you know the innards of the device. Its designers may have expected the unit to be fed with a current/votlage limiting resistor in the power line and it may or may not have a capacitor in the signal line.

Yes, many microphones have two pins. One is used for ground and the other is for the AC signal running on top of DC for supply. That corresponds to the 'capsule' in the Wikipedia diagram I referenced. Downstream from this (outside the 'capsule' in the diagram) the AC signal is decoupled from DC power by a capacitor. However, many systems run the three connections (power, ground and decoupled AC signal lines) separately out to the microphone unit.

Of the currently sold, Yaesu rigs for which I have the circuit diagrams this is the case for the FT-8900 & FT-857D and Yaesu microphones MH-48 & MH-42B6J. The microphone signal lines in their mic connectors are not powered; the power comes from another pin in the connector.

Measure the voltage between pins 1 & 7. I suspect it could be about 0V.

See the Wikipedia article here about electret condenser microphones. Note the circuit diagram on the right side of the page:
http://en.wikipedia.org/wiki/Electret_microphone

Pin 2 (5V) can be used for multiple purposes (such as backlighting) but it's likely that it also provides the supply voltage for the electret cartridge. Note the DC-blocking capacitor on the output in the Wikipedia circuit. Make sure you've got one in whatever you construct.

See also this thread for wiring:
http://www.eham.net/forums/VHFUHF/6375

There are Java-based loggers like JL and jaLog and JLog. These should be multiplatform applications.

Eric, it wasn't a silly question. Asking for feedback before implementing plans that might damage your equipment (or worse) is smart. For many new hams without EE or other electrical training in their backgrounds, DC power supplies are the among the first technical challenges faced. It's a good starting point to learn about the relationships between voltage, current, resistance, and power in a very practical application. It turns what you learned to pass the exams into working knowledge you will actually use.

And asking questions on the internet is helpful too, but I really encourage new hams to find clubs and Elmers nearby that can help. Face-to-face time often works best. Also, try very hard to drop by Field Day at a local club. It's the perfect venue to ask 'dumb' questions and get hands-on instruction from experienced hams. Talking with local hams also provides a great opportunity to receive used equipment for free or at a low price as most older hams have more power supplies (and other crap in their basements) than they actually need.