IC-E90 4m modification

[rob.rcs]

I've just made the modification on a colleague's IC-E90 transceiver to allow coverage of the 4m band, but a quick check on the wave meter shows that the output around 141 MHz is almost as much as on 70 MHz! Apparently there's another modification to reduce this spurious harmonic, but does anyone have any details on this filter circuit mod for the IC-E90?

[g8tok]

Yep, that's exactly what happens if you don't filter the radio. :)

The next thing that happens is that some very large gentlemen representing the emergency services come to see you and probably remove your radio, as you will cause interference to some important services that you will not be able to hear. :o

ML&S now recommend that the (modified) radio is only used with the supplied rubber duck, and that advice has been on www.70mhz.org for some time.

As to the modification, you will have to ask ML&S for their commercial information. Will they tell you; I don't know.

And, by the way, don't believe eBay sellers who broadband the radio and then tell you it works on 70MHz. It doesn't, and there are some test results on the 70MHz website. :rolleyes:

Best 73

Derek G8TOK

[rob.rcs]

As to the modification, you will have to ask ML&S for their commercial information. Will they tell you; I don't know.

Thanks for the reply Derek, I thought that the details on this modification were generally available and wasn't aware that this was "commercial information". I can easily make a 4m 'rubber duck' for him but I doubt that this will cure the problem, as the lack of adequate low pass filtering appears to be the cause of the problem. I'll contact the service department at Icom UK and ask what they recommend. Cheers! ;)

[Graham-G4FUJ]

I'm still enjoying the use I get from my properly modified E90 - thanks for that Derek! :)

73 Graham G4FUJ