Another thought - the 1N400x series, especially the 1N4002 and up, can make decent varactors. I've used them for FM modulating oscillators but I don't know what the actual performance is numerically, but I bet they have a bigger capacitance than the ones you are using. On Thu, Oct 20, 2016 at 1:54 PM, Sean Breheny wrote: > There are also older varactor diodes with a much larger capacitance, such > as the MVAM109 or MVAM125. There are a few sellers on eBay who have these= .. > I don't know if they are made anymore but there are still sources. I used > some in a receive-only remote antenna tuner I made. They have about 10x t= he > capacitance of the ones you are using now, and almost as large a cap rati= o. > > On Thu, Oct 20, 2016 at 12:16 PM, Van Horn, David backcountryaccess.com> wrote: > >> You could use mosfets to switch in capacitors in binary values, then >> maybe use a varactor or two for fine tuning. >> >> They DO still make the old 365pF variable caps, BTW. >> >> >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .