UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - 10M FM

G0HZU_JMR · 11th Dec 2018, 11:12 pm

Yes, it's definitely worth changing the filtering in some of these radios, especially if the MC3357 FM chip is being used. The two options I had for 10FM when I was first licensed was a converted Cobra 148GTL-DX CB and a Trio TS430S HF radio. I bought the TS430S new and ordered the FM module for it. The performance of the FM module was quite poor so I ended up adding my own mixer to replace the one in the MC3357 chip and I also did something to improve the (all or nothing) s meter response. I also changed the 455kHz filter to one with a narrower bandwidth. I did this within about a week of buying the radio as it was no good as a serious FM radio without these changes.

Looking back in my logbook I can see I had a local contact on 10FM about 30 years ago and it was a UK special events station in Essex that was running on 10FM. i.e. they had a GB0 callsign. I can remember hearing repeaters on 10FM back then when conditions were good.

During Christmas and New Year there is often a brief bit of sporadic E activity so it is definitely worth having a listen on 10m SSB or FM now and again around the end of December.

11th Dec 2018, 11:12 pm	#59
G0HZU_JMR Dekatron Join Date: Sep 2010 Location: Cheltenham, Gloucestershire, UK. Posts: 3,077	Re: 10M FM - any activity these days? Yes, it's definitely worth changing the filtering in some of these radios, especially if the MC3357 FM chip is being used. The two options I had for 10FM when I was first licensed was a converted Cobra 148GTL-DX CB and a Trio TS430S HF radio. I bought the TS430S new and ordered the FM module for it. The performance of the FM module was quite poor so I ended up adding my own mixer to replace the one in the MC3357 chip and I also did something to improve the (all or nothing) s meter response. I also changed the 455kHz filter to one with a narrower bandwidth. I did this within about a week of buying the radio as it was no good as a serious FM radio without these changes. Looking back in my logbook I can see I had a local contact on 10FM about 30 years ago and it was a UK special events station in Essex that was running on 10FM. i.e. they had a GB0 callsign. I can remember hearing repeaters on 10FM back then when conditions were good. During Christmas and New Year there is often a brief bit of sporadic E activity so it is definitely worth having a listen on 10m SSB or FM now and again around the end of December. __________________ Regards, Jeremy G0HZU