Very nice!=20 -----Original Message----- From: piclist-bounces@mit.edu On Behalf Of Sean B= reheny Sent: Wednesday, July 11, 2018 1:56 PM To: Microcontroller discussion list - Public. Subject: Re: [EE] Antenna design? I would recommend reading appendix A of my master's thesis :) https://ecommons.cornell.edu/bitstream/handle/1813/8346/thesis%20formatted.= pdf?sequence=3D1&isAllowed=3Dy It is an 11-page summary of antenna theory (that I had to include because m= y thesis advisor was not an antenna expert) With an efficient passive antenna (no amplifiers and no major losses that y= ou can reduce), you can't get more gain without being more directive. In ot= her words, if you cannot be directional, then making your antenna bigger th= an a half wavelength does nothing for you. This is true for BOTH transmit A= ND receive because passive antennas are reciprocal devices. A patch antenna is probably best for you. Any kind of linear antenna is goi= ng to have a null along the long axis of the antenna. This can be a problem= for the case where the robot is on one floor and the operator is on anothe= r floor. Colinear arrays only make this worse - they direct more radiation in a flat= disk and have an even wider null along the long axis. They are commonly us= ed for cell towers because all of the cell phones that need to access the t= ower are in a narrow range of vertical angle - radiation going up into the = sky (or listening for radiation from the sky) is a waste. Sean On Wed, Jul 11, 2018 at 2:37 PM, Neil wrote: > Okay antenna gurus, I can use some help here please... > > I'm using a 5.8Ghz video transmitter/receiver system on a robot (2D=20 > driving, indoor). These systems are popular with the drone-racing=20 > crowd, but most of the good antennas are either circular-polarized (so=20 > they are uniformly effective at most angles) or patch antennas which=20 > are apparently very unidirectional. Linear antennas have mostly gone=20 > away for this purpose. > > I'm trying to maximize signal strength/reception so the operator can=20 > be in a different room and on a different floor. For my purposes, I'm=20 > thinking a linear antenna on the transmitter side (robot) may be best=20 > though, as I can mount it vertically in the robot body, and perhaps=20 > use a patch antenna on the receiver side as that would have minimal=20 > movement. Or linear as well for the receiver. I understand that whip=20 > antennas are really crappy so would a straight piece of wire work=20 > better? I also discovered "collinear antennas" while searching. > > I have about 18-20" of room to put an antenna vertically inside the=20 > robot ... would having an antenna length of a multiple of the=20 > wavelength work better than just a single-wavelength antenna? > > So what say ye? > > Cheers, > -Neil. > > > -- > 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 .