> "Dave" <dave_g7...@...> wrote: > Thanks for that Skipp....I accept your opinions but > in that case why do some manufactures silver plate the > insides and some don't? > Cheers Dave UZN
Hi Dave, Please don't accept my opinions as gospel, always try to obtain information from multiple sources following up on the stated facts for accuracy. There are two major reasons considered by many people for silver plating coil and cavity surfaces. "Q and Oxidation" Let's talk about both in reverse order... [pasted text from another reply post] >> "I can't speak for the manufactures, but I think silver >> plating them would cut down on the chance of the cavities >> oxidizing over time. Silver does oxidize, just less/slower than bare copper. The environment becomes the relative pivot point in your choice to plate or nay. I have 1970's vintage bare copper cavities in clean, cool, dry locations that still look shinny/new. Many of the internally not silver plated Motorola T-1500 Duplexers are real-world examples still in active service. "Q is everything" if you really need it... but in this example you only "need enough Q" to get the job done. And in the cavities we're talking about here you should be able to obtain enough Q for the job. One of the rare examples I've really seen the obvious benefits of Silver Plating is in the field of NMR Probe Design & Construction. A way off topic application for this group... but proof to me there is real merit to silver plating if you need it. In many examples for UHF/VHF Amateur Duplexer applications I'd say silver plating is not an "in-stone" requirement. Just beneficial if you do... cheers, s. > > > "Dave" <dave_g7uzn@> wrote: > > > Hi All, I have rescently obtained a uhf pair of cavities > > > that are not silver plated inside (bare copper) They both > > > have an insertion loss of 3dB.... > > > > In this example the 3dB insertion loss is not is not > > affected (to any significant value) by the lack of silver > > plating. > > > > > If I were to get them silver plated what would the > > > improvement be? > > > > The person/business you pay to complete the plating has an > > improved income. > > > > > I have no idea how much it would cost but if the saving > > > was only about 0.5dB I wouldn't bother. > > > > Don't bother... > > > > > Your thoughts please? > > > > I try not to have any... > > > > > Cheers Dave UZN > > > > Never watched the show and I believe it was on the UPN out here. > > :-) > > > > On a more serious note... you might look around for pictures > > and descriptions of the very famous Motorola T-1500 series of > > cavities often made into various combination of duplexer > > assemblies. They are not plated and they work very well. The > > insertion loss is set by the probe type and position. > > > > s. > > >
