On 3 August 2011 05:17, David VanHorn wrote: > Given all the "how to"s on the net, I was somewhat surprised what > level of accuracy it takes to get a good return loss figure at this > frequency. =A0It makes sense scaling down from my experience at 144, > 432, and 915 MHz, but the interwebs suggest that pretty much any old > thing will give stupendous gain. =A0:-P > > The antenna itself is 75 ohms nominal, which does provide some > reflection, but setting the length of the feedline to an odd multiple > of half wavelengths minimizes that issue, and provides another > dimension to tolerance. > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > Yes, the dimensions are critical. I brought a "standard" cheap 2.4GHz antenna into work and put it on the VNA. Horrible return loss. Once trimmed to the correct length it now works significantly better - I'd estimate more than 3dB improvement. And the adjustment required was less less than a mm. RP --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .