By "ground-plane", do you mean the mesh wire network? FWIW, the case is=20 metal and the antenna still just hangs outside the box. Can I use the=20 metal box for any part of this ground plane? BTW, the unit/case is not grounded to earth... I'm using a 2-wire DC=20 wall wart to power the box. And on the PC side, power is provided by a=20 USB-to-serial converter. Cheers, -Neil. On 8/4/2016 6:35 AM, rubenjonsson@bredband.net wrote: > Second that. You should be using a "counterpoise" (ground plane or > rods) with a 1/4 wave whip antenna to get correct impedance match and > optimum performance. A whip antenna is actually only half of the > antenna. > > /Ruben > > On Wed, 3 Aug 2016 23:06:49 -0600, David VanHorn > wrote: >> Quarter wave and counterpoise? With antennas "short" generally equates >> with "sucks". I have seen a counterpoise add 6db even to a helical >> "ducky". >> >> On Aug 3, 2016 10:58 PM, "Neil" wrote: >> >>> Hi all, >>> >>> I built a quick device for a friend that lets a receptionist send >>> messages from a PC to a desktop display device, and vice-versa with a >>> handful of canned responses. The PC side uses VB to serial (via USB), >>> to a USB-to-serial interface, then a 433 Mhz serial module, through an >>> IPEX-to-RP-SMA interface, to a short whip antenna. The desktop display >>> device also has the same 433 Mhz serial module (controlled by an >>> Arduino), to the same IPEX-to-RP-SMA interface cable, then to an >>> identical whip antenna. >>> >>> I'm not getting the range necessary... I'm getting 35-ish feet indoors >>> (through one wall), and need about 100 feet indoors (in an office >>> through a glass wall). I've tried a 433 Mhz PCB antenna, but that got >>> me less distance than the whip antennas. And the whip antennas are >>> listed as being for 433 Mhz. >>> >>> Any clues on how to get better distance? I'm looking for 433Mhz >>> amplifiers, but they're a bit pricey. I'm short on time, so hoping to >>> find a ready-made solution (if an amp is necessary), rather than having >>> to build one. >>> >>> Cheers, >>> -Neil. >>> >>> >>> -- >>> 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 .