Hi Hue, You have received some expert advise and an offer to help, but I'll add this. When I had a similar question about a Celwave mobile duplexer, I contacted their applications engineering department with all the label info and they e-mailed the information and tuning instructions for the unit. I don't know if Decibel would do the same. You may also find some useful information on the repeater builder website. <http://www.repeater-builder.com/antenna/ant-sys-index.html#duplexers> 73 Mike kc9doa On 28 May 2014 at 20:54, Hue Miller wrote: > I have 3 diplexers made by Decibel Co. that are marked "450-470 > MHz". > Can these somehow be tuned lower, or are they scrap metal? > tnx > Hue K7HUE > ______________________________________________________________ > Antennas mailing list > Home: http://mailman.qth.net/mailman/listinfo/antennas > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Antennas at mailman.qth.net >> This list hosted by: http://www.qsl.net > Please help support this email list: > http://www.qsl.net/donate.html