It does almost the same if there is also a calibration procedure prior to the measurement: http://www.testequity.com/documents/pdf/N9322C-making-reflection-measuremen= ts.pdf On Wed, Jun 4, 2014 at 1:44 PM, Joe McCauley wrote: > Does a spectrum analyser with tracking generator & directional coupler no= t > do the same thing? (Measuring reflected energy from the antenna.) I have > the TG output connected to the through port of the coupler & the antenna > connected on the other side. The coupled port of the coupler is connected > to the 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 > 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 > > move 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 > > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > -- > 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 .