Uniden USDS-100 Digital Scanner

  class60 Beginner

Hi Guys,

Noticed that Andrews Communications Systems is selling the “Australian” version of the Uniden USDS-100. One of the features of this model is the capability of receiving DMR Tier 3 (via an additional payable download).  Living in Brisbane most of Queensland Rail Control is now Tait DMR Tier 3. (Some of the yards like Acacia Ridge still use “AM” for shunting).

Looking at the net plenty of information regarding theory of operation and even frequencies but I have been unable to find any information of anyone “scanning” QR DMR Tier 3? Seen several post on scanner sites but been a novice was left a bit unclear as to their meaning.

Request that any members might have information on scanning QR DMR Tier 3, or Uniden USDS-100. Thinking of purchasing USDS-100 but it is an expensive outlay so I like as much information as possible before hand!

Any information would be greatly appreciated.
Regards, Mick

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  neillfarmer Chief Train Controller

Lot of people interested in this but I guess nobody wants to risk $950. I see there are also other cheaper digital scanners capable of DMR but will they pick up QR? If there was one in a shop you could put some batteries in it and see if it picks up QR suburban TCR before purchase
Neill Farmer
  class60 Beginner

Hi Neill, thanks for the reply. Agreed it would be good if I could go into a store and “try” out a USDS-100 scanner. Unfortunately in Brisbane it appears that most Uniden agents do not have radio scanners available (especially the more expensive models) off the shelf. Visited a large communication store at Rocklea several years ago now looking for a external antenna for a scanner, and the salesman noted that since QLD Police had gone “digital” for communications the “bottom” had dropped out of scanner sales. As a result they no longer have scanners available off the shelf but were more than happy to order a item in, which I believe is still the case.

There is an Australian scanner site (Aussie scanners.com.au) and I am going to send a enquire to this site regarding QR DMR. Also give Andrews Communication a call as they may also have some information on this subject.

As you noted several other digital scanners have DMR available, however from my limited knowledge of DMR (Digital Mobile Radio) has 3 Tiers, Tier 1, Tier 2 and Tier 3. Several of the digital scanner have Tier 1 & 2 but not 3. For QR scanning you need a scanner to receive DMR Tier 3 (I believe?) Tier 3 is trunking operation, and supports voice and short messaging. Wikipedia has a good article on DMR which gives a brief explanation better than I ever could!

If I get a definitive answer regarding USDS-100 about receiving QR DMR Tier 3 I will let you know. If I don’t spend too much at the upcoming Brisbane model train show I might yet take the “plunge” and buy the scanner? See what I hear back from Aussie Scanners?

  railscan Locomotive Fireman

Location: Beside a railway line somewhere
First and foremost, the railways of Queensland as opposed to Queensland Railways is certainly a mixed bag when it comes to radio, but AM is definitely not part of the mix.

QR in the south east and one or two other areas is using Tier III DMR for its operations. Analog FM is still used as well but is slowly being phased out.

Aurizon has just rolled out a TETRA platform for train control etc on lines under its control. Again some FM can still be found but it too is being replaced by TETRA. For most part TETRA is largely unscannerable (if that is a word). Only one receiver can monitor TETRA but cannot track it or display talkgroups and associated network information. SDR devices and computers can also be used but a limiting. TETRA uses four timeslots within a 25 kHz channel, each timeslot is 6.25 kHz wide and all four can be used simultaneously.

Back to the QR DMR and DMR in general. Forget about Tier I, it is basically used for kids toys in Europe and Asia and is effectively useless. Tier II is conventional while Tier III is trunking. QR is trunking. Trunking is basically described as using a pool of frequencies at each site, whereby a user is assigned a frequency from the pool, after which is returns to the pool for the next subscriber. Sites are normally linked by various methods including but not limited to RF or IP connections.

DMR employs two timeslots of 6.25 kHz each which makes up a standard 12.5 kHz RF assignment. These timeslots form virtual channels. The timeslots can be assigned specific functions like voice only, data only, voice and data, telemetry and GPS to mention but a few. Both timeslots can be used simultaneously.

It appears from your post that you are somewhat of a novice when it comes to the newer digital formats and the new breed of scanner. Without meaning any offence if that is the case then don't purchase a USDS100, instead look at a good used UBCD436PT or the US version BCD436HP. Firstly they will cost you significantly less but can still do the same job. Maybe they don't have all the pretty lights but you do pay a premium for those lights.

The 436 can do DMR (paid upgrade) just as well as the USDS100. This will get you started and if you decide to continue then upgrade to a USDS100 can follow. You can sell or keep the 436 as a backup. Ebay is a good source for the 436's often with the DMR upgrade already installed.

There is no easy way I can provide enough information in this forum to get you started in monitoring QR DMR. I would be typing for a month of Sundays. Again without offending, you are going to start a journey on a very steep learning curve. I can only say to learn as much as you can about the scanner and the systems you want to monitor and don't look to others to spoon feed you. While that may sound tough, learning yourself means that can work things out when something goes wrong or changes. Besides information on forums like this and others is often wrong or inaccurate. Present company excluded, of course.

Post here your decision.

  class60 Beginner

Hi railscan, thanks for your detailed reply. As a beginner/novice in scanning, especially in the newer digital formats it is very much appreciated. No offence is taken at your post, this exactly the information as a beginner I was look for.

Regarding scanners, your recommendation for UBCD436PT seems the best option for me given my “experience” and budget. First option is to pick up a good unit from eBay if possible as you noted (will add the paid DMR download if required).

As you stated it will be a journey with a steep leaning curve, at least now I have a starting point to begin the journey and the learning.


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