Analog Signal Chasing

[Ubbe]

Is there a scanner that could make this activity easier I would be interested to hear more

As already mentioned the TRX-1/2 can be used. They never open squelch immediately on a carrier but first check what type of signal it is, which can be annoying, but in your case will just stop briefly on a signal without unmuting and then continue to search for only analog signals.

But they are limited having only one search range and doesn't use a bandplan that can be edited but supports several different countries that hopefully will match.

Some scanners have a sound squelch that also works as a data squelch but will always let you hear the datasignal for one or two seconds.

Best way for you would probably be to create scan tables, one range with a unique step size in each department and one VHF or UHF band in each system, for your 436 and/or SDS100 to match the exact bandplan used in Australia and sit and monitor for an hour or two and permanently avoid all data channels you can hear.

I set a negative delay to -10sec so it will continue to scan even when the scanner finds a new data channel. Then I import the recorded files into Universal Scanner Audio Player to analyze the result and any data being decoded can then be manually set to avoid in the scanner or in Sentinel. After a while all data channels in your area will have been found and avoided and the recorded files on the SD card will only have analog channels that then can be set to a normal delay of +10sec.

I would recommend to not use a SDS100 to search for unknown frequencies, it is too unreliable as if a signal are -80dBm or stronger it will, due to intermod issues in the scanner, also be found at other frequencies that are not the correct one and will confuse you. I only use my BCD536 and sometimes the UBCD3600 when doing searches for new active frequencies. If you have ProScan you can probably connect an extra audio cable to your 325 or 996 and also use that to record files. USAP also supports Icom files so that could also be an option if it can be programmed to follow your bandplan.

/Ubbe

 

[K2RNI]

View attachment 204699

I also still find wireless mics on there, around big churches especially and some show venues as well as my ENG mics I been use since 2012.

 

[W3DMV]

The Icom R-8600 has a function called "VSC", voice
squelch control which performs this function. I use
it all the time when looking for analog signals while
searching...

 

[pb_lonny]

The Icom R-8600 has a function called "VSC", voice
squelch control which performs this function. I use
it all the time when looking for analog signals while
searching...

I think the R6 has the same, I am not sure how "well" it works.

 

[VK3YMML]

FYI all, I am in Melbourne, Australia so we don't have any transmissions in the 700-800mhz band except maybe for Tetra.

I am using the Frequency Search function of the scanner and mainly using the 400Mhz - 510Mhz range which is used by many commercial business however as mentioned I am wishing to bypass any digital signals.

The issue with the "avoid" function is that most scanners have a limitation on the amount of frequencies that it can store and then you get the inaugural "Avoid List Full" or words to that effect on the scanner.

Recording the audio would only work if a scanner can be connected to a PC and it registers the frequency that the signal came from otherwise its would not really aid the search.

A Whistler TRX-1 I have checked Ebay and they range from AU $300-$800 and let alone the shipping to Australia so not really a viable solution.

The other option is using a rasp-pi and a sdr which I have however to date I have not located a suitable solution at this stage.

 

[pb_lonny]

I run AutoStore on my BCD325P2 and UBCD396XT a lot of the time, I then scan this system and lock out anything digital. I also run it at times with CTCSS/DCS tone search enabled, if a frequency is found with one of these tones, I know it is analouge.

How are you saving your results? I have an Excel spreadsheet which I update and compare to the ACMA database. This has some logic around the groups / modes and dates, to highlight anything new / interesting.

Have you used the recorder on the 436 or SDS100 much? I use to use Discovery mode a bit on mine, this then gives you audio recordings you can review and see what is being recorded as analouge or digital.

 

[VK3YMML]

I run AutoStore on my BCD325P2 and UBCD396XT a lot of the time, I then scan this system and lock out anything digital. I also run it at times with CTCSS/DCS tone search enabled, if a frequency is found with one of these tones, I know it is analouge.

How are you saving your results? I have an Excel spreadsheet which I update and compare to the ACMA database. This has some logic around the groups / modes and dates, to highlight anything new / interesting.

Have you used the recorder on the 436 or SDS100 much? I use to use Discovery mode a bit on mine, this then gives you audio recordings you can review and see what is being recorded as analouge or digital.

I am using the 436PT to record however I need to clear the card before it reaches capacity. With respect to the ACMA database sometimes you need to alter the distance as some frequencies are filtered out. For instance I came across a new frequency in use in the 505.xxx Mhz range though the matches I get with ACMA currently dont line up with the traffic heard via the frequency. My only thoughts are either its being used by another party illegally and or the transmission power or maybe some tropospheric ducting is in play.

I have a spreadsheet that I currently manage. The SDS100 is currently running a different digital network so that has been sidelined for now. I have other scanners connected with ProScan which I have done in the past however I just obtained a 996XT based on some of the advice I will trial it with the -10 delay and see what impact that has. I will also check on the CTCS/DCS tone option.

Part of this active search is to show that Analog is not dead and there is still plenty out there to find and monitor.

 

[Ubbe]

I am using the 436PT to record however I need to clear the card before it reaches capacity.

You can switch to a 32GB SD card and it will hold up to a month of continuous 24/7 recordings but as you probably don't have a constant activity there will be times when the scanner are silent so will allow the scanner to work unattended for more than a month until the card is full. Using USAP you can sort and filter the logs and instantly listen to all recordings.

As Paul mentioned there's also Discovery mode in some scanners that are supposed to compare any hits to what are already in the database and in Favorite lists and ignore any hits found in those files. It can also avoid an unknown frequency after 3 hits that would prevent getting hang up on data channels as it also has a timeout timer for a recording.

This works fine in any old firmware like a HP-1 but Uniden messed it up in newer firmware (old firmware for 435/536 where initially OK) and it stopped working in that way. Even when all those functions are available still some of them can no longer be used in BCD and SDS scanners and it's only the recording and logging functions that work as they should but none of the compare and automatically avoid.

/Ubbe