Radio improvements – Tweaking things to make them better

I like things to work well. I like to tweak the best possible performance out of equipment and as such I’ll look into what I can do to make things better and do it. I’m not counting my current HF aerial in this as that was just thrown up at the spur of the moment although the fact that I’m planning on replacing it does show that I’m keen to improve things.

For example, when I did some aerial work on my VHF station last year, I wanted the best possible and practical coax so I used EcoFlex 15 from the output of my linear into the masthead pre-amp and then rather than use RG213 from the radio to the linear and the output of the pre-amp, I used short runs of EcoFlex 10. Each length only gives a marginal improvement but as far as I’m concerned, all these small improvements add up to a better system.

I don’t like PL-259/SO-239 connectors at all. Because of this, I replaced the SO-239 sockets on my linear with N-Types and had the SO-239 in the 144MHz stage on my FT-847 swapped out for an N-Type as well. The N-Type is a far superior connector.

The Yaesu FT-847 is a good radio but it can be improved on. The front end isn’t the most selective in the world and because I like to operate VHF contests from home, I soon realised that it was going to be a struggle for me because there’s a big station, G0VHF/P who operate just a few miles away from me. Some investigation showed that I could dramatically improve the front end of the FT-847 by replacing the supplied filter with an INRAD #702 2100Hz 8-pole crystal filter so this was done and has shown to be a very effective modification. I also found the headphone output volume to be a bit low so a resistor was swapped to increase the audio levels. The 847 is also known to suffer from drift when a crystal warms up so a small polystyrene hat was added to help increase the stability.

I’ve also read quite a lot of reports suggesting that the HF noise floor of the FT-847 can be improved by replacing all the switching diodes with low noise Schottky diodes. I’ve got these diodes and they will be fitted shortly.

What I can’t get my head around is the attitude of some people who either can’t, don’t or won’t understand the reasoning behind this. I often talk to fellow amateurs and in conversation I’ll mention the mods I’ve had done to the FT-847 only to be met by incredulity. A common response is “What’s the point, it’s a good radio”. The point is straightforward, it may be a good radio but if it can be improved by doing some basic modifications then surely that has to be a good thing.

I can understand the reticence to dive into a modern radio with a soldering iron for fear of breaking something and to an extent my feelings are the same and because I’ve not really used a soldering iron for a good years I’ll openly admit that all the mods I’ve mentioned above that have already been completed were done for me by Richard at Coastal Communications in Clacton-on-Sea but now that I’ve had the iron out again and have been doing some solder melting I’m feeling confident enough to have a go at doing the switching diodes myself.  Many years ago I had a job in a factory for around nine months where I was wielding a soldering iron all day so it didn’t take me long to get myself back confident again.

So the reason for this post is simple – You may have the latest all singing and all dancing radio but there’s a good chance that there are some easy modifications you can do to improve it.  Have a search around and see what you can do, you may be surprised.

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