Radio stays in tx

#1
Initial set up of features very excited - however after 1 day of operation something went wrong - the input radio ( tried a couple radios Baofengs and Puxing 888k ) the input radio locks on TX - tried fresh batteries, ordered 2 cables both same TX, tried switch #3 reset, - this lock on TX happens even with repeater turned off and batteries removed - any other ideas ?
 

Ian ZL1VFO

Moderator
Staff member
#2
Usually radios getting stuck in Tx are a result of the attached cables crawling with RF and jamming the PTT on.
If you connect a dummy load to the aerial connector, and the PTT stops locking on, then it go some way to confirming this.
Usual fixes are checking the integrity of the coax (Braid may be sparse or have come detached) and perhaps running the PTT cable several turns through an RF choke near the radio.
73
Ian ZL1VFO
 
#3
Thank for your prompt response - tried to attach a pic - file to large I will try on Facebook - but anyway tried suggestion of 2 ft jumper of ultra low loss RG8 - X coax cable no apparent defects ... Connect radio to repeater still the radio goes into TX even with batteries removed from the repeater .... I will see if I have a core to make a choke as suggested - how about cutting the braid from old RG8 wrapping around input cable ? ... Thanks again for your prompt response - Gary L KB1DVU
 

Ian ZL1VFO

Moderator
Staff member
#4
Another possibility is the wiring between the radio and the repeater, or the radio's PTT method - whether it is combined with the mic audio or not. See if the radio still goes into transmit by itself when the RJ45 is unplugged from the repeater, but the other end of the cable is still plugged into the radio. If it does, then it suggests something might be amiss in the cable's wiring, or possibly the radios plugs aren't in fully.
Otherwise, with the RJ45 plugged into the repeater, try toggling DIP switch 4 - from the schematic it appears to either combine or separate the PTT line (RJ45 pin 5) and the mic audio (RJ45 pin 3). Different radio use different methods for PTTing, so that may be related to your problem
73s
Ian ZL1VFO
 
#5
PROGRESS ! I'm pretty sure I had tried the dip switch#4 already - anyway this morning I tried the SD1 and no lock on ! - I then did a couple test transmissions and it repeated TX as it should ( now I'm getting excited) ... So next I want to try the features - very limited success dtmf 0 it does play back last heard - attempt to record an announcement dtmf ##31 -the message repeats - dtmf 0 the message repeats - dtmf ##21 message does not play back SD1 plays back the tones - try dtmf 0 and plays back the tones last entered - does not seem to be responding to diagnostic commands either such as ##96 Report Usage Count - SD1 plays back tones last entered - tried DIP switch 3 reset - pretty much attempted above tests all the same - again thank you for your prompt attention and suggestions
 
#6
Also please note when I initially tested the SD1 I was able to record and play back the announcement, set a security code, and use the dtmf ##96 Report Usage Count
 

Ian ZL1VFO

Moderator
Staff member
#8
If the repeater appears to respond to some DTMF commands, but not all, then one possibility is the amount of 'twist' or variation in levels between the high and low group of tones. I had one friend's handheld which would not work with the local IRLP node - some digits were recognised and others not. Ended up being about 12dB of twist between tone groups, which was too much for the DTMF decoder to handle. Ended up having to alter the serial Resistor and capacitor values in his handheld and managed to get the twist down to about 3dB, which works fine with everything we tried it on.
The DTMF decode appears to be done in software inside the MC9S08AW60 rather than using a dedicated DTMF decoder IC like a MT8870, so I'm not sure how tolerant it is of twist.
One suggestion would be to try another radio or 2 with a DTMF keypad and / or perhaps change the received audio levels into the repeater and see if that changes anything.
73
Ian ZL1VFO
 
#9
Ian - ZL1VFO - thank you for all the support and suggestions - On June 11th I was a staff member (1st Aid and Com's ) at an event that tends to attract Survivalists and Preppers with the focus of attendees to retrieve the pre-recorded announcement message. I documented 181 tests not including tests done by me unless I was demonstrating to another individual where I had a display at the Aid Station. 160 tests the ADS-SR1 performed as it should with 21 failures ( failures more than once using same radio was documented as 1 fail in the tally) - those who saw the unit work properly seemed very interested. Not sure what you consider acceptance performance for a device that may be used in an emergency situation. I have returned ( I see by USPS tracking it has arrived at Santa Maria, CA) with detailed notes of my testing and observations. I am very interested in your tests and if the device in general seems to have intermittent issues or I just got a glitchy one