SX 600 simple user guide
SX 600 is simple non-accurate easy-to-use SWR meter located in brmlab subsection named radiolab. Here easy guide for measuring handheld radio antenna is descibed
Official operation instructions
basic operation
prerequisities
SX-600 SWR meter (see
brmsklad for location)
cables to connect antenna to radio (see
brmsklad for location)
antenna which is measured
TX source (your radio, it's preferable to have some which can give decent power to the circuit - 4W is sufficient)
experimental setup
connect radio to SWR Radio channel (for commonly used radio freq sensor 2 TX connector - if unsure, see
official documentation)
connect antenna to SWR antenna channel (second plug on same side, in this case sensor 2 ANT connector)
if you're measuring just SWR and not forward or reflected pwr, you don't need to connect SWR to external power source
usefull notes
for results closer to application situation geometry of experiment simillar to real situation is preffered, if you're measuring antenna for handheld radio, it's good to grab connector near antenna itself to simulate geometry simillar to when you're holding radio and communicate.
geometry of experiment can crucially change SWR (for detailed results see
example below)
measurment itself
set aproppiate power range (for 4W handheld radio 5W is good choice)
turn cal knob just to 0 (turn it CCW to minimal position)
switch Function switch to CAL position
open channel on radio and turn cal knob to triangle mark (it's on end of the scale, right upper corner)
close channel on radio
switch Function switch to SWR position
open channel on radio and check for SWR value on scale, it's second big red line from top.
calibration of scale (that means CAL cycle) is function of frq, that means that instrument needs to be recalibrated on every frequency change to give reliable results.
for deeper insight don't hesitate to see official documentation it's pretty short and easily understandable.
* Measuring forward and reflected power and calculating SWR is more precise, but also more time-demanding.
example
measuring of Nagoya NA-701 from CN distributor
antenna was obtained through unverified channel, so it can be clone, but price was pretty friendly. Antenna is marked as 144/430 MHz and it's used mainly on ~173-177 (SD70) and ~466 (PMR) channels, so three wavelenghts were measured and recorded, also shift by geometry of experiment was monitored. Results are collected in Table 1 below.
results
<table>
table 1 NA-701 144/430 frequency-SWR values measured by SX-600
| frq | | SWR {a} | SWR {b} |
| | | | |
| 144.000 | | almost 10 | around 2-3 |
| 177.000 | | notably more than 10 {c} | slightly over 10 {c} |
| 446.000 | | 2 | around 1,8 , maybe slightly better |
</table>
notes:
a) antena freely hangs from table
b) cable which was connected to antena was held just under antenna to simulate real world enviroment
c) SWR start's to be pretty unprecise in those values
<table>
table 2 NA-701 144/430 frequency-Pf,Pr values measured by SX-600
| frq | | Pforw | Prefl | SWR |
| | | | | |
| 172.000 | | 2.6 | 0.9 | 12.8{a} |
| 172.000 | | 4.5 | 3.2 | 11.8{a,b} |
| 446.000 | | 1.7 | 0.4 | 2.9{a} |
</table>
notes:
a) calculated by equation from documentation SWR = [sqrt(Pf) + sqrt(Pr)]/[sqrt(Pf) - sqrt(Pr)]
b) measured another day, antena hanging freely
measuring original baofeng antenna
<table>
table 3 - measuring original baofeng antenna frequency-Pf,Pr values measured by SX-600
| frq | | Pforw | Prefl | SWR |
| | | | | |
| 172.000 | | 4.8 | 3 | 8.6{a} |
| 446.000 | | 3.2 | 0 | 1{a} |
</table>
notes:
a) calculated by equation from documentation SWR = [sqrt(Pf) + sqrt(Pr)]/[sqrt(Pf) - sqrt(Pr)]
measuring china NA-771
<table>
table 3 - measuring china RH771 antenna frequency-Pf,Pr values measured by SX-600
| frq | | Pforw | Prefl | SWR |
| | | | | |
| 172.000 | | 3.8 | 2.4 | 8.7{a} |
| 446.000 | | 2.4 | 1.3 | 6.6{a} |
</table>
notes:
a) calculated by equation from documentation SWR = [sqrt(Pf) + sqrt(Pr)]/[sqrt(Pf) - sqrt(Pr)] , measured “hanging freely”
measuring taiwan NA-701
<table>
table 3 - measuring china NA-771 antenna frequency-Pf,Pr values measured by SX-600
| frq | | Pforw | Prefl | SWR |
| | | | | |
| 172.000 | | 4 | 3.5 | 30{a} |
| 446.000 | | 1.8 | 0.4 | 2.8{a} |
</table>
notes:
a) calculated by equation from documentation SWR = [sqrt(Pf) + sqrt(Pr)]/[sqrt(Pf) - sqrt(Pr)] , measured “hanging freely” - looked same from hand
original wouxun antenna
<table>
table 3 - measuring original wouxun antenna frequency-Pf,Pr values measured by SX-600
| frq | | Pforw | Prefl | SWR |
| | | | | |
| 172.000 | | 2.6 | 1.1 | 4.72{a} |
| 446.000 | | 1.9 | 0.9 | 5.4{a} |
</table>
notes:
a) calculated by equation from documentation SWR = [sqrt(Pf) + sqrt(Pr)]/[sqrt(Pf) - sqrt(Pr)] , measured “hanging from hand”