I have a TK-790 and am having not really some issues but annoyances while scanning. I have it set to dual priority scan and am having some issues with it not picking up the whole conversation on a non-priority channel. I have the Look Back Time (A) set to .5 sec and the Look Back Time (B) set to 1.0 sec and am missing anything from the first second to almost 5 seconds of a transmission on a channel that is not set as priority. To try and remedy this problem I set the Lookback times to 2 sec and 3 sec respectively and nothing seems to fix it. I was wondering if anyone ran into the same issue and had a fix to it. Also, I have tweaked the Dwell times and they don't seem to make any difference either way.
-
To anyone looking to acquire commercial radio programming software:
Please do not make requests for copies of radio programming software which is sold (or was sold) by the manufacturer for any monetary value. All requests will be deleted and a forum infraction issued. Making a request such as this is attempting to engage in software piracy and this forum cannot be involved or associated with this activity. The same goes for any private transaction via Private Message. Even if you attempt to engage in this activity in PM's we will still enforce the forum rules. Your PM's are not private and the administration has the right to read them if there's a hint to criminal activity.
If you are having trouble legally obtaining software please state so. We do not want any hurt feelings when your vague post is mistaken for a free request. It is YOUR responsibility to properly word your request.
To obtain Motorola software see the Sticky in the Motorola forum.
The various other vendors often permit their dealers to sell the software online (i.e., Kenwood). Please use Google or some other search engine to find a dealer that sells the software. Typically each series or individual radio requires its own software package. Often the Kenwood software is less than $100 so don't be a cheapskate; just purchase it.
For M/A Com/Harris/GE, etc: there are two software packages that program all current and past radios. One package is for conventional programming and the other for trunked programming. The trunked package is in upwards of $2,500. The conventional package is more reasonable though is still several hundred dollars. The benefit is you do not need multiple versions for each radio (unlike Motorola).
This is a large and very visible forum. We cannot jeopardize the ability to provide the RadioReference services by allowing this activity to occur. Please respect this.
TK-790 Scan Issue
- Thread starter egrs40
- Start date
- Status
How many channels do have in the radio?
OK, lets talk scan. First off, I have a TK-760 right next to me and my biggest gripe is the scan algorithm which slows the scan considerably no matter what I do. I miss seconds off of channel, much like what your complaint is about the 790. My opinion is the 790 does better on scan than a 760.
How does this all work? The simplest scan would be through channels programmed as CSQ (no QT) and no priority. All the radio has to do is change to a channel, lock its VCO, and check for channel activity (is the squelch broken?) then move on. It can do this pretty quick and to the user, scan would seem acceptable for a few dozen channels.
Now lets add QT to the receive on a channel. Now the radio stops on a channel that is unsquelched AND it has to decode the QT. A tone QT may take upwards of 50mS to decode, while a DQT is more like 150 mS. Only when the decoder decides the QT is false, does the radio move on. If you have ten channels active, all with DQT, it will take about 1.5 seconds to step through them all. Quite slower than just breezing by inactive channels. You can miss the first few words in this scenario.
Lets add one priority channel. During scan the radio (at the interval of lookback A) detours its normal scan sequence to check its priority channel (this could be during scan or stopped on a non-priority channel). This is the normal flup-flup-flup you hear on a non-priority channel as it checks the priority channel. If there is no activity on the priority channel, it quickly returns to scan (or receiving the non-pri channel) and continues with its lookback A time. If there is activity on the priority channel the check stops, checks the QT and if it is valid stays there and unmutes the speaker. If the QT is false, the radio sets a flag for the priority channel and reverts to lookback time B. You then go to scan (or non-pri) and the slower lookback B takes over, just looking for priority channel activity. If it goes back and sees it is still unsquelched, it assumes it is still the wrong QT and ignores it and scan (or non-pri) resumes. Only when it goes to the priority channel and sees no channel activity, the flag is reset and the priority check is now the faster lookback A. There is scan in a nutshell.
Now for your problem. The only thing that would slow the scan down from a reasonably fast rate to something slower would be the stopover to check QT. It would be slowed further if you use first and second priorities depending on how your squelch breaks. Also the non priority channels will slow on the activity. I guess what I'm trying to say is that if your squelch is too loose and noise tends to trip it, it forces the radio to stop and check QT (what does it know, it's dumb to what is a real transmission). Try a higher squelch setting and see if that helps. Or try this, disconnect the antenna from the 790 and try transmitting next to it on a portable on priority and non-priority channels. If the scan works well then, either your squelch is too low or you are in one hell of a co-channel congested area.
How does this all work? The simplest scan would be through channels programmed as CSQ (no QT) and no priority. All the radio has to do is change to a channel, lock its VCO, and check for channel activity (is the squelch broken?) then move on. It can do this pretty quick and to the user, scan would seem acceptable for a few dozen channels.
Now lets add QT to the receive on a channel. Now the radio stops on a channel that is unsquelched AND it has to decode the QT. A tone QT may take upwards of 50mS to decode, while a DQT is more like 150 mS. Only when the decoder decides the QT is false, does the radio move on. If you have ten channels active, all with DQT, it will take about 1.5 seconds to step through them all. Quite slower than just breezing by inactive channels. You can miss the first few words in this scenario.
Lets add one priority channel. During scan the radio (at the interval of lookback A) detours its normal scan sequence to check its priority channel (this could be during scan or stopped on a non-priority channel). This is the normal flup-flup-flup you hear on a non-priority channel as it checks the priority channel. If there is no activity on the priority channel, it quickly returns to scan (or receiving the non-pri channel) and continues with its lookback A time. If there is activity on the priority channel the check stops, checks the QT and if it is valid stays there and unmutes the speaker. If the QT is false, the radio sets a flag for the priority channel and reverts to lookback time B. You then go to scan (or non-pri) and the slower lookback B takes over, just looking for priority channel activity. If it goes back and sees it is still unsquelched, it assumes it is still the wrong QT and ignores it and scan (or non-pri) resumes. Only when it goes to the priority channel and sees no channel activity, the flag is reset and the priority check is now the faster lookback A. There is scan in a nutshell.
Now for your problem. The only thing that would slow the scan down from a reasonably fast rate to something slower would be the stopover to check QT. It would be slowed further if you use first and second priorities depending on how your squelch breaks. Also the non priority channels will slow on the activity. I guess what I'm trying to say is that if your squelch is too loose and noise tends to trip it, it forces the radio to stop and check QT (what does it know, it's dumb to what is a real transmission). Try a higher squelch setting and see if that helps. Or try this, disconnect the antenna from the 790 and try transmitting next to it on a portable on priority and non-priority channels. If the scan works well then, either your squelch is too low or you are in one hell of a co-channel congested area.
Last edited:
- Status
