Does a spectrum analyser with tracking generator & directional coupler not = do the same thing? (Measuring reflected energy from the antenna.) I have th= e TG output connected to the through port of the coupler & the antenna conn= ected on the other side. The coupled port of the coupler is connected to th= e RF input of the analyser. Thanks, joe -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of= Vasile Surducan Sent: 04 June 2014 09:17 To: Microcontroller discussion list - Public. Subject: Re: [OT] Matching an antenna to a VHF TX/RX If you have a network analyzer will be much easier. Just connect the antenn= a 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 th= e trimmer capacitor if has one) until the max absorption appears to be on y= our 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=20 > > 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=20 > move analyser to the other boat. > > I recall that the farming community I once belonged to were adamant=20 > that a two way radio (UHF) would fail to work if the antenna was=20 > mounted on the roof of a vehicle and the two way radio was mounted=20 > directly under the antenna inside the cab. > > justin > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive=20 > View/change your membership options at=20 > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t --=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 .