Alan, agree with the rare location. In the early Eighties I went to the Isle of Man, took a 2 metre beam (OK I know this is a MOBILE forum) . It was like listening to a trout farm at feeding time!! all for me!
A "GD" call is worth a thousand CQs.
To quote VK3BJM "What makes a pleasant change to sitting in the shack waiting for rare DX? Going out to become rare DX!"

Cheers de Tony

Evidently a contest, what the other station is after is a serial number.
Example
If I was to work you and I hadn't worked anyone else.

**** from G8YMW, you are 5/9 001
The serial number is the number of stations you have worked in the contest at that point

The choke should be as close to the aerial as poss.
The idea is that RF goes up the coax on the centre conductor and the inner of the braid. What is happening (which the choke is supposed to stop) is RF is coming BACK down the outer of the braid aka the "Common Mode Currents"

As for sorting out the root causes, I'll hand over to people that know more than me.

73 de Tony

I have seen somewhere (A UK CB forum) someone had trouble with noise from his diesel car.
It seems that the injectors are controlled by electrical impulses. What this lad did was to wind the wires around ferrite rings close to the injectors which knocked the noise down well.
Wish I could find the thread!!

Though the ciggie lighter is do-able, but as you say, it will bring up the noise. If the 10 metre radio is to be permanent, then tee into the direct power line(remembering to pull the in-line fuses first). Then again, tee into it anyway.

Possibly its the solder material (silver solder?). You might have to drill them out or maybe its time to bin them.
Sorry
Tony

The Moxon is a 2 ele yagi (sort of) so radiator to the station to be contacted.
The front to back ratio is very good so pointing the reflector towards the wanted station.... not recommended

FT736 ?, not in the UK.
It had 2 and 70 as standard with options for 6 and 23 but not 4 .
Was 220 an optional module over there?

Probably the same reason no one makes a multi mode transceiver for 70 MHz (4 metres) (yet? rumours abound).

Just a late reminder,
The National Hamfest 30th September and 1st October at the Newark and Nottinghamshire Showground
Run by the Radio Society of Great Britain and Lincoln Shortwave Club
Bring and Buy run by RAF Waddington ARC

Alan,
I dont know how 6 metres works on your side of the Pond but over here (Unless there is a contest on) 6 is deserted unless the band opens and as polarity goes out the window with Ionospheric Propagation then whether you are vertical or horizontal shouldnt matter.
Another point, a horizontal aerial, to perform at its optimum needs to be 1/2 wavelength  away from the car's bodywork or it tends to fire skywards.
OK a halo for 6, 10 feet above the car is going to cause no end of problems when on the move (PC Plod's attention, whacking bridges, overhead wires and trees)
I know this is 2 metres but demonstrates what I'm on about

http://www.qsl.net/vk3bjm/mobile.htm

My understanding is that /mm is for TIDAL waters. If the river is not tidal where the vessel is then its /m. I dont know if that is the same as what you're saying Dan?

Does reducing the radio's power help? I'm wondering if its a power supply problem

Go for a mobile antenna, no your RF will not get lost in the feedline, the feedline will be shorter on your bike than in a car. Fasten the aerial to a luggage rack at the back, coax routed under the seat and petrol tank. Jobs a good'un.
Study the local bike Plods, might give you some more ideas

The Halo antenna is as good as anything for mobile SSB on 2 metres. Most halos come with a 1/2 metre mast. The problem with that is that the car will act as a reflector and shove the RF skywards.
I suppose the ultimate omni would be a "Cloverleaf" aka "Big Wheel" but it MIGHT be a touch OTT for mobile.
I have used a halo "/p" at 4 metres agl with a roach pole and drive-on mast base with 5 watts from an FT817 and my ODX was Northern Ireland at 396 km (Admitted his system was doing the work)

Anyways, see what this gentleman has done

http://www.qsl.net/vk3bjm/mobile.htm

Dont forget being cross polarised will give about 20dB loss of signal hence a halo with negative gain ref dipole will ALWAYS be better than a vertical