If you have a network analyzer will be much easier. Just connect the antenna on one port (with the whole cable you are using between the antenna and the input port) and see the S11. Then tune the antenna lenght (or adjust the trimmer capacitor if has one) until the max absorption appears to be on your required frequency. I think between 153 and 156 MHz you should do nothing unless you have small emitting power. On Wed, Jun 4, 2014 at 6:02 AM, Justin Richards wrote: > On 4 June 2014 03:38, Joe McCauley wrote: > > > That is the next step I think, how far apart do you put the antennas? I= 'm > > guessing they can't be too far apart. > > > > They are close, approx 20 m. If you had a portable B that you could > position the same distance from each and save trace to disk so you can mo= ve > analyser to the other boat. > > I recall that the farming community I once belonged to were adamant that = a > two way radio (UHF) would fail to work if the antenna was mounted on the > roof of a vehicle and the two way radio was mounted directly under the > antenna inside the cab. > > justin > -- > 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 .