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Baofeng UV-5R: receiver sensitivity measurements | Radioaficion Ham Radio

Baofeng UV-5R: receiver sensitivity measurements

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Baofeng UV-5R receiver sensitivity measurements

Many people consider the Baofeng UV-5R the successor of the suprisingly popular UV-3R/UV-100 models. As far as I could ascertain at this moment of writing, Hans PD0AC [1] was the first who published some results of actual measurements on his Baofeng UV-5R. In a private communication with Hans I promised him to measure my Baofeng UV-5R. In this contribution my results are presented.

Measurement conditions and procedure

The Baofeng UV-5R was put into 'dual watch mode', i.e. menu item 7 (TDR) was set to 'ON'. Menu item 5 (W/N) was set to 'WIDE'. Selected VHF and UHF frequencies were 145.000 MHz, and 432.000 MHz respectively. A Rohde & Schwarz SMS2 (old, but still going strong ;-) signal generator was used as RF-source. Calibrated output level accuracy of the R&S SMS2 is ± 1.5 dB, minimum signal level is -137 dBm (0.03 uV). The Baofeng UV-5R was connected to the signal generator, and the injected signal was varied with 1 dB steps.

The SMS2 has a tone generator, but I always to use the 'quieting' method to measure sensitivities of FM-receivers. Quieting makes it very easy to tune FM-receivers because e.g. frontend coils can be tweaked to minimum audio meter reading, assuming that the IF and discriminator are 'on frequency'. Although being a topic of debate, in practice it appears that 20 dB quieting equals 12 dB SINAD [e.g. 2].

With an 'open receiver', i.e. squelch level was set to '0', I defined three states:

a) when I could hear a difference between 'no signal' and 'signal'

b) 10 dB quieting (meter reading is ~3/10th of the noise level)

c) 20 dB quieting (meter reading is 1/10th of the noise level)

For squelch levels 1 - 9 (menu item 0) the injected signal was increased with 1 dB steps until the squelch opened within one second, and subsequently decreased until the squelch closed.

In table 1 (next page) the results of my measurements are presented.

@145 MHz 20 dB quieting was measured at -125 dBm (0.13 uV), while @432 MHz this value amounts -131 dBm (0.06 µV). @432 MHz I reached the limits of my RF-generator.

The performance of squelch levels 1 - 7 @145 MHz measured equal, while @432 MHz squelch levels increase with ~1dB steps.

Although I don't want to draw conclusions, I consider my Baofeng UV-5R receiver very sensitive.

I did not measure other parameters (like strong signal behaviour etc.), so how the UV-5R behaves with an external antenna is perhaps for somebody else to find out?

Baofeng UV-5R receiver sensitivity measurements

Table 1. Baofeng UV-5R receiver sensitivity measurements by PA3FYM

Addendum:

The RF-output of my UV-5R was measured with a HP-432A power meter in conjunction with calibrated attenuators. Battery status: 'fully charged' (i.e. green led on the charger).

Menu item 2 (TXP)

'HIGH'

'LOW'

145 MHz:

3.4W ± 50mW

0.85W ± 50mW

432 MHz:

3.6W ± 50mW

0.90W ± 50mW

Hans [1] asked me to measure the frequency accurary of my Baofeng UV-5R too, because some people claim the UV-5R being 'off frequency'. I assumed that the transmit frequency is an indicator for the PLL accuracy for both RX and TX, as I did not open the UV-5R to measure the local oscillator frequency itself. Measurements with a HP-5326A (yes, nixie tubes! ;-) and a homebrew prescaler, in conjunction with a calibrated rubidium standard as time base, revealed the following results (sample time: 10 sec, accuracy 10 Hz):

UV-5R display

frequency


145.000 (MHz)

145.000.040 MHz

(+ 40 Hz)

432.000 (MHz)

431.999.930 MHz

(- 70 Hz)

My UV-5R frequency accurary @145 and 432 MHz is (far) better than 0.5 ppm, which is very good.

References

[1] http://hamgear.wordpress.com

[2] http://www.repeater-builder.com/measuring-sensitivity/measuring-sensitivity.html

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