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PostPosted: Sun Jun 03, 2018 4:17 pm 
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Joined: Sun Jun 03, 2018 1:09 pm
Posts: 4
I'm working on building a direction finding rig using an RS-UV3, an Arduino Uno, an LCD/keypad shield (Sainsmart, clone of a Robotshop or Velleman design I think), and eventually an outboard attenuator.

I'm having quite a bit of trouble getting sane results. The RS-UV3 seems to work fine when I'm just talking to it with an ftdi board, but with the Arduino connected (with or without the ftdi; the sketch sends debugging output to the usb serial) and running, I see varied incorrect behavior:

  • Squelch often closed in spite of SQ0, TM0 settings
  • SS values sometimes seeming about right for no received signal, but not changing when I transmit with a handheld right next to the RS-UV3
  • Most recently, SS command output of wildly invalid numbers like
    Code:
    SS: -21145
    (I can see this at the same time through the ftdi route if that's also hooked up)
  • I've even seen apparently correct behavior once or twice, but it's not at all repeatable

I've jumpered the RXD and TXD pads to pins 11 and 12 on the Arduino, and am running at 19200, but with 100ms delay between each character to eliminate any potential data overrun issues. These are the only things jumpered to the Arduino headers on the RS-UV3.

The LCD is on Arduino pins 4-9. The buttons are on pin 0, analog.

The initialization I send to the board at power up is:

Code:
AF1
AI0
AO1
DP1
DR0
GM0
HP1
LD2
PD1
PW0
SQ0
TM0


If the sketch queries frequency or channel parameters it does get sane responses.

The RS-UV3 board is Rev. D. I upgraded the firmware today from 2.1 to 2.4, but it didn't help.

I'm sure I must be doing _something_ stupid, but whatever it is, I'm missing it. Does anyone see what I'm doing wrong here?


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PostPosted: Sun Jun 03, 2018 7:30 pm 
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Joined: Sun Jun 03, 2018 1:09 pm
Posts: 4
Ok, after a bunch more fiddling and an accidental discovery, I think it's working.

By using the PD1 command, I was apparently turning the RDA chip _off_, not on as the documentation seems to indicate. Using PD0 gets me sane behavior: signal strength numbers in range and responsive to the presence of signals.

The behavior of the ST led with LD2, SQ0, and TM0 is also not intuitive to me. With no received signal, the ST LED is off in that configuration. I was expecting it to be on, because the squelch should be open. Maybe an RDA chip behavior?

After increasing wait time for the RS-UV3 board to boot, and being sure to have the sketch send the radio a carriage return and then wait a further fraction of a second before talking to the radio, I was able to significantly reduce the intercharacter delays and post-command wait times without problems.

I do still see the radio power up without sending a banner or responding to commands, occasionally. I also occasionally see the status report from the VU? command get in a state where the 'V' character gets replaced with a control-a. This latter lasts until I power cycle the radio.


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PostPosted: Mon Jun 04, 2018 5:53 am 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Yes PD1 is power off and PD0 is power on. I'll update the command reference.

With SQ0 and TM0 you'd expect the squelch to be open. I'll try to figure out why it's not. The code just echoes the state of the RDA's squelch line.

On the power-up issue, maybe the new DC-DC converter comes up more slowly with certain input voltages. I'll do some tests to see if I can duplicate the problem.

I haven't seen the condition where the VU? command get's confused but I can't say for sure how many times I've actually issued a VU? command. I'll try it a few times and see what happens.


73,
Jim WA2EUJ


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PostPosted: Mon Jun 04, 2018 9:26 am 
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Joined: Sun Jun 03, 2018 1:09 pm
Posts: 4
Jim, thanks for the comments. I really appreciate the transparency and response you provide for this product.

The ST led off occurs with SS values around -100 dB, and a rubber duck attached. I noticed later last night that when I remove the duck, the SS value drops to around -130, and the ST led comes on. Not sure what to make of this.

Remember, this is a UV3, not a 3A. For development, I've been feeding 12V from a couple of different supplies with plenty of current capability.

Regarding the VU? output corruption, when the sketch starts up, it issues two queries. Later, it sends the sequence of static settings commands (list in my first post), and also the variable ones (frequency and volume) at least once, and perhaps multiple times. I _think_ I've always been through multiple cycles when the corruption has appeared. It's not breaking my sketch, because I don't validate the VU: label.


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PostPosted: Tue Jun 05, 2018 5:12 am 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
There's more than one squelch in the RDA. The Tone squelch that you can turn off with TM0 then there's a signal level based squelch that you set with the SQ and SR commands. There's also a signal-to-noise squelch which I haven't programmed access to and I'm not sure exactly where it's set.

If the SS goes from -130 without an antenna to -100 with an antenna then the antenna must be picking up a good amount of noise or other signals are present that are overloading the receiver. In which case the S/N squelch may be determinig that no signal is present and keeping ST off. If you suspect that out-of-band signals are swamping the receiver. You might try one of our band pass filters if you are only using a single band. You can issue the SN command to see what the receiver is measuring for noise.

As for the lock-ups, version 2.4 should have cleared up the issue. The library call for I2C was blocking (it sat there and waited forever for the right response) somewhere around 2.2 or 2.3 I rewrote the I2C library to re-try if the correct response didn;t occur and eventually reset the bus.

73,
Jim WA2EUJ


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