On Sat, 26 Dec 2015 12:24:54 -0000, "gareth"
wrote:
Anyone have an inkling of what you get for your £350-odd?
You can probably get a fair idea of what's inside and how it works
from the following links. The major limitations of the MFJ-259/269
analyzers is the inability to sweep a frequency range and the tendency
for static electricity or too much RF to blow out the front end
diodes.
MFJ-269 repair:
http://802.11junk.com/jeffl/MFJ-269-repair/
MFJ-269 schematic:
http://802.11junk.com/jeffl/MFJ-269-repair/mfj-269-schematic.pdf
MFJ-259 calibration:
http://www.w8ji.com/mfj-259b_calibration.htm
http://www.ok1cjb.cz/pdf/390_kalibrace.pdf
Build Your Own Antenna Analyzer for under $50
http://www.hamstack.com/project_antenna_analyzer.html
http://www.hamstack.com/hs_projects/k6bez_antenna_analyzer.pdf
For single port measurements, I prefer to use a return loss bridge:
https://www.google.com/search?q=return+loss+bridge&tbm=isch
http://www.qsl.net/n9zia/wireless/pics/rtrn_loss_bridge.png
It doesn't give reactance information or draw a Smith Chart as with a
real VNA. It also requires an RF sweep generator and an oscilloscope.
With a collection of small bridges, I can sweep and measure most
anything from VLF to wi-fi:
http://pe2er.nl/wifiswr/
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558