Wednesday, April 18, 2012

Baofeng UV-5R: Off Frequency Receive Problem?

There have been more than a few reports of an off frequency receive problem (here, here, here, here, here, and there).

Remco, PA3FYM, did some testing and had no problems with his UV-5R. Full results here.
"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. 


  1. It was interesting to see that Remco came up with the same excellent accuracy too.

    More copies of the UV-5R are on the way. Before they meet their new owners, these will be subjected to our test bench too, so we can rule out two lucky strikes in a row.

    Hans / PD0AC

  2. Hans,

    The following statement is key: "I assumed that the transmit frequency is an indicator for the PLL accuracy for both RX and TX". The apparent dispute is whether the RDA is being programmed with some type of data offset on the RX side of the chip.

    It appears that you have verified TX portion of the UV-5R to be accurate. Would you be able to follow up and verify the RX portion as well?

    By the way, I greatly appreciate your great work for the group. Thank you!

  3. Hi,

    PA2TSL and me checked the TX and RX accuracy, two separate measurements. I'm not in a position to comment on Remco's work, from whom the quote is you posted above.