TRX-2: ZM Threshold, ZM Slope, and ZM Delay

Status
Not open for further replies.

anelson5004

Member
Premium Subscriber
Joined
Mar 8, 2011
Messages
187
Location
Cedar Bluff, VA
Would someone please explain in detail what the ZM Threshold, ZM Slope, and ZM delay are on the Whistler TRX2?

thanks
anelson5004
 

Machria

Member
Premium Subscriber
Joined
Apr 24, 2014
Messages
509
Location
Long Island, NY
Would someone please explain in detail what the ZM Threshold, ZM Slope, and ZM delay are on the Whistler TRX2?

thanks
anelson5004
Well, they all have to do with the ZM. The first is the Threshold, the second is the Slope, and the last is the Delay! I know this because I translate furniture assembly instructions for a Chinese company!! :D


Sorry, couldn't resist! I too would love a good explanation of these....
 

BrianG61UK

Member
Joined
Nov 13, 2016
Messages
354
Location
England
Well, they all have to do with the ZM. The first is the Threshold, the second is the Slope, and the last is the Delay! I know this because I translate furniture assembly instructions for a Chinese company!! :D


Sorry, couldn't resist! I too would love a good explanation of these....
ZM = Zeromatic.

If I understand correctly this is what allows the scanner to find the (near) exact frequency when searching even if the step size the scanner is searching doesn't result in it landing exactly on frequency.

I guess they control how the scanner homes in on the correct frequency.

I can't really see why they're configurable, it should be up to the manufacturer to know and use the best values for them.
 
Joined
Jul 6, 2011
Messages
23
Location
Netherlands
It's not an AFC, it's the opposite. It the received frequency are not spot on it will ignore it.

/Ubbe
Thats exactly what happend to my TRX-1 after updating to firmware 5.2
The scanner won't stop anymore on active frequencies when in limit search mode, or spectrum sweeper
Also no audio when using the tuning function on an active frequency.
In scan mode everything was working fine.
After unchecking the Zeromatic check box in the menu (default = ON) the TRX-1 is working fine again in search and tune mode.

I am living in Europe and use the UK Bandplan. Frequencies i used to listen to in UHF band should be on spot using the 6,25 Khz step. (For example 429.8875 or 461.01875)

Mark
 

TAbirdman

Member
Joined
Oct 10, 2014
Messages
594
Location
MO
After unchecking the Zeromatic check box in the menu (default = ON) the TRX-1 is working fine again in search and tune mode.

Mark
Did you mean Flex Step as I don't see a Zeromatic on/off option? It could be right in front of me too, just say'n lol :)
 

Machria

Member
Premium Subscriber
Joined
Apr 24, 2014
Messages
509
Location
Long Island, NY
So this: <http://forums.radioreference.com/showthread.php?t=20450> is wrong?
That's a great explanation, thanks for the link/thread. I knew what it did, I did not know why/what to really use it for. Thats explanation nails it, and it's from 2005. ;)
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
thats ok

Thats ok,I went to search and check the boxes ON,I thought ON was checked,in search But.... then it would only stop on analog frequencies.
You want them UNchecked,now it does stop on NXDN,P25 and DMR...:lol:
 
Joined
Jul 6, 2011
Messages
23
Location
Netherlands
Did you mean Flex Step as I don't see a Zeromatic on/off option? It could be right in front of me too, just say'n lol :)
As far as i know there's no option to turn Zeromatic on or off in EZ scan.
You can turn Zeromatic off in the TRX's menu; press menu and scroll down while in search-, tune- or spectrum-sweeper mode and unchek the zeromatic box.
For me the search, tune and spectrum-sweeper only worked as they should after turning Zeromatic off...

Mark
 

Ubbe

Member
Joined
Sep 8, 2006
Messages
5,514
Location
Stockholm, Sweden
So this: <http://forums.radioreference.com/showthread.php?t=20450> is wrong?
Yes, that is totally wrong. It is explained in older GRE scanners manuals. Older scanners used to have a selection of 5KHz turbo step in search and it would stop on frequencies that where 5KHz off, or more, and by using ZeroMatic it only stopped on the correct frequency. The scanners tuning need to be correct and if using ZM makes it skip channels that are supposed to match then something is wrong.

edit: I did a search with ZM off and it stops 6,25KHz both before and after the correct frequency with any strong DMR site. So it works as it should in my TRX-2. Values are Delay=50 Threshold=1180 Slope=520

/Ubbe
 
Last edited:

BrianG61UK

Member
Joined
Nov 13, 2016
Messages
354
Location
England
Yes, that is totally wrong. It is explained in older GRE scanners manuals. Older scanners used to have a selection of 5KHz turbo step in search and it would stop on frequencies that where 5KHz off, or more, and by using ZeroMatic it only stopped on the correct frequency. The scanners tuning need to be correct and if using ZM makes it skip channels that are supposed to match then something is wrong.

edit: I did a search with ZM off and it stops 6,25KHz both before and after the correct frequency with any strong DMR site. So it works as it should in my TRX-2. Values are Delay=50 Threshold=1180 Slope=520

/Ubbe
They why are there THREE parameters Threshold, Slope and Delay?

How could you possibly need three if it's just a simple variable size window the signal has to be within?
 

ynot58

Member
Joined
Jul 11, 2007
Messages
26
Trx1 zeromatic

Had lengthy discussion with whistler and they're right that zeromatic must be on for spectrum sweeper to work correctly.
I've been using it and gets everything dmr nxdn etc including inputs. With zeromatic off you think your getting more but your getting same frequencies offset 3 different ways. General settings reset defaults only resets values and doesn't disturb stored information for scanning.
 

ynot58

Member
Joined
Jul 11, 2007
Messages
26
Spectrum sweeper simply attenuates the radio and searches for transmissions that are very close to you
 

Ubbe

Member
Joined
Sep 8, 2006
Messages
5,514
Location
Stockholm, Sweden
It is searching with what looks like 1MHz steps per second and use a wide bandwidth filter to sense the RF level over at least a 1MHz frequency range. If it detects RF it goes down to searching using the stepsize of the bandplan, usually 3.125Khz or 6.25Khz per second until the RF goes under the detectable level.

When it searches with 1MHz steps it is not using the squelch so it will be less sensitive when only using RF level detect but it will switch to SQ mode when it switches to bandplan mode. If you want it to only trigger on close call transmissions you can enable the attenuator function to be used only for sweep mode. If you see the display only indcate bandplan search and not 1MHz steps then you have a too high interference level and if you want to use sweeper you have to attenuate the antenna signal using a variable attenuator until you see that it switches to 1MHz steps.
Of course it could also be that you have a lot of valid transmitters in your area that force the sweeper to switch to bandplan search.

/Ubbe
 

Ubbe

Member
Joined
Sep 8, 2006
Messages
5,514
Location
Stockholm, Sweden
They why are there THREE parameters Threshold, Slope and Delay?

How could you possibly need three if it's just a simple variable size window the signal has to be within?
You have to consider that the PLL/VCO are not quick enough and need a settling time before you can start to detect the signal and needs a delay time. The VCO reacts differently and settling time will change depending of the frequencies so I guess the slope value are used to compensate for that phenomen.

/Ubbe
 

ynot58

Member
Joined
Jul 11, 2007
Messages
26
Use stock antenna on spectrum sweeper as it tunes to all frequencies being an all band antenna. I tried radio shack 800 antenna with bad results like too many lockups and missing frequencies. I live in heavily populated area of all formats nxdn, dmr etc and stock antenna works best for spectrum sweeper with zeromatic on or off . I sat in one spot trying everything like antennas and settings.
 
Status
Not open for further replies.
Top