multimode upgrade

[skyrider]

ok i have a ham international multimode 2 which i have had new from the early eighties and as you all know it is am /fm but not true uk fm so apart from changing the circuit board which i really dont want to do as i want to keep the radio original is there any electronic box or similar that i could plug in to get uk fm thanks (you have probably heard this about a dozen times before )

[NM1020]

A good old radio, I've got two, had one of them since the early 80s!

Other than using it 'as-is' and twiddling the KC shift on 'high' and 'super-high' bands on FM, the only other options are to fit an EPROM board from 'Spectrum' or one of the latest mods from 'MicroChipz', see:- https://www.youtube.com/@MicroChipz/featured

Then do the FM audio mod. However, if your radio is a mint condition example in original box etc. then it might be best to leave it original as an increasing in value collectors item. It'll still be usable on FM, but you'll need to do a bit of KC shift twiddling and put up with folk saying you're muffled or quiet, although a Ham-Master (or equivalent) base mic turned up full helps a lot in this respect.

[skyrider]

yes it is still in really good condition with the hand book and box it came with , i have been told in the past jus to keep it in the cupboard and just get a modern sideband

[Mitch]

If it's pristine then perhaps better to leave it unmodded, clean examples are hard to find of any old radios these days.They can still deteriorate in storage if not used, had it happen twice here (Concorde mk1 repaired, Lafayette 1800 scrapped), sometimes things just need to be used to keep them working. But do you want to use it? Plus one for the microchipz boards, I'm using two so far, they work well. The other option is use the multi for ssb and mids, and get an FM rig for UK band plus antenna switch for a similar cost.

[NM1020]

It sounds like it's best left as it is in its original condition. However, you can still use it on sideband and it'll get the 'zeros' with use of the KC shift (or coarse tune control, if you like), but without a 'mod' you won't get the 'splits' (between the 20KC jumps, or perhaps we should say 20KHz these days) and that brings us to the second problem for UK FM. There's four channels that you won't be able to get fully onto on UK FM and that's 5, 30, 35 and 40, but you'll near enough be able to get them with the KC shift fully clockwise to basically get away with it. So your Multimode is still a very usable radio today, even without any modifications.

[Mudslinger]

The FM audio mod is essential IMO. It makes them sound pretty decent on that mode. Without it they are barely useable.

The SSB bias needs sorting out too for good SSB audio.

Once done they are very good radio. (I have a boxed one too)

[NM1020]

Actually, my Multimode that I've had since the early 80s is, and was, an absolute dog, bought in a job lot of radio junk for 25 quid, if I remember rightly. It was burned out (usual RF choke coil) and I fixed it (rewound the coil, not many turns) and it's never been a problem on SSB, and that's without touching the RF output biasing, which is more than can be said for ANY of the Tristar 747 sets and their equivalents, which are always awful. I did modify the FM on mine, but folk always said that it didn't sound that bad as it was in its original state for a Multimode II. I think a lot depends on the particular batch of crystals used at the time of original manufacture, some accept being bent (or pulled) off frequency more than others. The bottom line is that the idea of modulating the band crystals for FM was a terrible idea in the first place and it makes you wonder what the designers were thinking back then. I actually think that it was an AM/SSB only design and this new fangled FM was just thrown in as an afterthought to get the rig into production in the cheapest and quickest way possible...they probably thought that FM would never catch on, so it didn't matter.

I actually quite like to hear the sound of an unmodified 'mufflemode' with a Ham-Master wound full throttle in a large sparsely furnished room, but it certainly makes a big difference when you modify them to modulate the VCO rather than the band crystals. That UK CB repair chap happened to catch me on my 'modified' Jumbo on UK FM at the end of one of his repair videos the other day while he was clicking up the channels after he'd repaired a rig. It was quite funny hearing what my Jumbo sounded like at a distance - just a few seconds, but immortalised for all eternity on YouTube, like a few of the other 'locals' to him have been over the years!

[Mudslinger]

He won't like you appearing on his channel with an "illegal" radio.

Do you have a link to it?

[NightProwler]

I love watching his videos when he gets a radio with an illegal modification. The best one was when he had one with a 10KC jump fitted, He ripped it out to save the owner doing 6 months in prison. I almost wet my Y fronts laughing