It has been set to duplex =1, CTCSS (J) = no and carrier = usb. It receives and transmits fine but PTT doesnt get released and PTT stops only when the timer of the radio stops it. Whenever the radio transmits there is a string of Hungup ‘DAHDI/pseudo-XXX’ until it stops transmitting. I get choppy response when echo is enabled. COS status shows cos flashing from clear to keyed continuosly.
When I set carrier to usbinvert I do not get response from echo but the beeping continues and asterisk shows Hungup ‘DAHDI/pseudo-XXX’ for 10 lines or so.
I would greatly appreciate if someone could help. Do let me know if additional information is required.
When you say “PTT doesn’t get released”, are you saying that Asterisk is showing PTT as “keyed” or Asterisk is showing it as “Clear” yet the radio continues to be keyed? The former would be a config issue and the latter would be an electrical issue.
Thanks for the response. I believe it would be the former
The PTT status shows up as keyed but flashes once in a while. COS input and COS output keep cycling between clear and keyed continuosly until tx stops (I think physically due to ToT on the HT).
PTT status shows up as clear along with COS in and out once transmission ends.
When I toggle transmit test tone, it’s the same long tx.
Would you have any config recommendations to look into?
Sounds like a tough one. I have only a generic reply.
You are going to have to use process of elimination.
I might look for RF in the lines. Remove the COS line and see if the behavior continues.
It is also possible that the threshold voltage logic on the cos is not high/low enough.
Or even just close and the rf is tipping it.
PTT’s normally have no voltage and sink to ground when active.
Sometimes hard to get your head around it if you are a bit novice to it.
A transistor buffer between the radio and sound fob might help with borderline voltages.
I was wondering why no GND connection to the FOB. Perhaps that was in the directions you followed. I wonder if the radio ground is the same as computer frame ground.
A plus must have a minus somewhere to have current flow.
Someone may have more to offer as I am not familiar with the radio, attachment points or settings for it. This activity is not consistent with a setting, unless a file is corrupt.
Just some quick looking points if you are still looking.
One last thought. If the TX is spikeing the cos on transition, you might add this parameter.
rxondelay = 10 ; number of 20ms intervals to hold off receiver turn-on indication
To your simpleusb/usbradio .conf
That 10 number is 200ms of delay 1/5th of a second
that the rx is active before a COS toggle actually occures.
Thank you @Mike ! I am a complete novice and it is all flowing over my head.
The radio is in its cradle, the fob is in the computer, it didn’t mention anywhere in the guide to connect ground. While fidgeting with it, I did connect radio ground to fob ground but there was all sorts of humming and weird sounds.
I have set one fob with a 2n2222a transistor and one with a 2n3904, both give same results. I have even made 2 more fobs just in case I messed up the soldering on the chip, but that all seems fine and I believe as @N8EI mentioned it could totally be a config issue.
I will give the rxondelay option a try, the transistor buffer thing looks difficult. I do not understand what to do there haha
If COS is toggling constantly, it’s most likely that you’re never finishing a complete transmit cycle to allow PTT to release before COS gets toggled again. It’s very unlikely to be a configuration issue and most likely an electrical problem. What exactly did you tap on the Baofeng UV82 as “COS”?
Looking at the diagram at this allstarsetup.com and I think there’s an electrical mistake in that diagram (without tracing out the circuits on that fob). There should be a 10k resistor between the COS tap on the UV-82 and the COS pin. Bridging the 10k resistor between those two pads is likely still connecting two open collectors without a pull up/down resistor. Try adding a 10K directly in series between the COS tap and the pad.
I added a 10k resistor which cleaned up the uv82 tx audio and stopped the cos cycling however the PTT continues to say clear yet still doesn’t get released on the uv82.
The continuous dingdong hungup dahdi issue went away with the rx delay option mentioned by @Mike
I have taken the points on the uv82 from hamvoip website (Modifying the UV82 for Allstar) and then connected them directly to the fob (except for ground). Screenshot is attached below.
I do see that they have added COS to a smaller chip on the side instead of how it usually is on the main chip on a baofeng 888s. Should I move it over to that point instead? Would that make a difference? COS connection point is labelled in the image on this link (https://hamvoip.org/hamradio/UV82_mod/images/Schematic-Baofeng-COS%20connection.jpg)
I can connect it to the leg on the bigger chip which shows continuity with the labelled point.
One overriding things you need to know about Baofengs is the innards change slightly all the time. Directions that works for one particular production run may not work perfectly for another and fiddling is required. That’s why many people use an SA818 chip on a board instead of a Baofeng.
Is your COS detection functioning properly now? If so, I wouldn’t mess around with moving it elsewhere.
Regarding PTT, the tune menu is now showing clear but PTT on the radio is still triggered? Measure the following with a volt meter:
The voltage between PTT and GND before any radio transmit
The voltage between PTT and GND during expected PTT (i.e. ASL show keyed)
The voltage between PTT and GND after expected PTT (i.e. ASL shows clear, UV82 still transmitting)
#1 should be a floating voltage somewhere above 0.5v and below 3v #2 should be 0v #3 is the interesting thing to know, if it’s rising up beyond the cut-off for the floating value
If the voltage isn’t going back to #1, you have a circuit issue that’s pulling PTT low enough after keydown that it’s not releasing the PTT.
Adam, the diagram above for connection points is what I would use.
To know absolute, we would have to look at the full radio schematic.
Looking at the board really says nothing. The schematic looks right if it’s location is correct with the diagram.
That us about all the guidance I have to that topic. No experience with either radio.
You might want to put a meter on that to see the voltage toggle high/low when sq is open before you make the cos attachment…
I tested value as @N8EI stated with 2 sets (I didnt knnow which gnd to use);
ptt and gnd on fob
Measures to around 3.3V
Multimeter starts beeping and acts weird
same as 2
ptt and gnd on uv82
Measures to around 3.28V
Multimeter starts beeping and acts weird
Same as 2
Ground point heats up a lot and starts flashing 0L and various other voltages, too fast to copy (even goes up to 400Vto 0 to blank with a lightning symbol flashing) when ptt gets keyed with test tone.
Voltage goes back to 3.2V after ptt stops.
I had verified that the boards looked similar however i can open it again to confirm the guide and my set are the same or identical.
Just a note again on PTT
Most on radios are 0vdc when not active (check with continuity
and short to ground when active.
Make sure you are testing the right way. It is conceivable that there may be a voltage on some radios when no active ptt but not the norm.
A meter in ‘auto mode’ may flip around a bit and be confusing.
Manual is best.
A Continuity test normally has a beep sound when it detects a short and that should show when the PTT is active. Touch the probes together for a pre-test.
A voltage check to the ptt line on a digital meter may just jump around when INACTIVE.
(float) There is no current associated with it.
Sorry Mike, but this is not completely accurate. In analog signalling like this, a circuit can be low, high, and then “float”. Low will be 0v when measured with a multimeter in normal state since low should be pulled to reference ground for the whole circuit. High will be whatever the +VDC supply of the (sub)circuit is - usually 5v, 3.3v, or 12v when measured between a high pin and ground. A float voltage will be something between the voltage transition edge between what’s “close enough” to low or high. For example, measuring pin to ground for a circuit at float in a 3.3v DC system will be somewhere between 1 and 2.5v.
Generally, in these types of logic state, the line is not “low or high” as is often discussed. Between TTL especially, a circuit is rarely “low” or “high” in a binary state at the ends of the voltages. If a circuit is active “low”, then voltage will be either 0v (active) or above 1v (not active). If a circuit is active “high”, then voltage will be 3.3v (active) or under ~ 2.5v (not active). Unless there’s a specific reason to pull the line to the opposite end of the signal, it just floats.
So in a situation where COS is active high, and high VDC is 3.3, then active will be ~ 3.0V when measured from pin to ground. When COS is not active high, then the voltage between pin and will be something between 0v and 2.5v.
In the situation where PTT is active low, then PTT will be triggered when the voltage is pulled to ground and measured as 0v between the pin and ground. PTT should release when the voltage breaks the ground threshold for the transistor.
Seesawing between 400V and 0 and the pad overheating sounds bad and dangerous. Although… 400V also seems pretty unrealistic.
I changed the cos point on the radio as well to rule it out but it is the same issue. Inside, mine looks like a newer version since Chinese electronics usually write the date in yymmdd format. The guide was 161105, mine is 171230 V5. Other components and tracks look similar.
All of my fobs have been modified in the same way so I get consistent results across the board. I have ordered some more and will modify them according to some other guides and see if that changes anything.
On the handset side, everything is fine. When I disconnect it from the fob, it operates as expected.
@Mike when I measure the voltage at idle by touching PTT and ground, it shows 3.2 but as soon as i switch the multimeter to continuity, PTT gets triggered on the HT.
400 is definitely incorrect as I was holding the ground wire at that time it was just the multimeter acting up, not knowing whats going on. Current went from positive to negative. This flashing/beeping also happened when only ptt wire was touched during transmission by positive probe and negative was not touched to ground.
When only ground was touched, it went from around -200mV during expected tx and -900mV in the prolonged tx tail.
@N8EI In the meantime, could I solder on some other resistors or components on the existing fobs to alleviate the issue?
So I am not at all sure what i was doing wrong then but the measurement went flawlessly, no jumping around this time. (I do not remember if i changed the fobs, today was a long repeater maintenance day)
3.2V PTT to UV82 GND ----- 3.3V PTT to Fob
-18mV to -30mV with UV82 GND ----- -2.2V to -2.35V with fob gnd
-180mV to -220mV approx UV82 GND ----- -2.6V to -2.7V fob gnd
The probes were not removed while taking readings so negative values were as they appeared on the multimeter.
Sorry i missed your response about low, high and float as it seems it was very close to when I posted. Thank you @N8EI for the information.
@Mike Thank you for the post. I skimmed through it. Will mark it to read later and respond if I can.
You definitely have an electrical circuit problem if your fob ground and radio ground are different. That makes it sound like you don’t have a common ground between the radio, the fob, and the Pi. Those all have to be tied together.
Ok I might be doing something fundamentally wrong here, but my UV82 ground wire is hanging out of the handset. I have attached the wire to the handset ground point but didn’t hook it up to the fob (I did some tests with it which gave humming and since I didn’t see it attached to a handset in the guide and it also didn’t show ground wire in the fob, I left it out).
Should I connect the handset ground wire to;
The fob ground, i.e. any point on the fob that shows continuity to the left most USB pin e.g. transistor emitter leg to HT gnd wire connection,
The PC metal body
The PC internal ground (would have to find that)
I will post updates here as to how it goes.
I have ASL3 installed in debian on a tinyPC. RPi body connection is ground so for me would would ground be inside the motherboard? I can also do a measurement test without the HT connected if that would help identify the issue.
and it is all flowing over my head.
