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An introduction to....

Uniden Dynamic Memory Scanning

I confess I used to be scared that I wouldn't understand it, but it turned out to be quite simple in the end. I hope I can convince you too!

Back in the old days, a simple 100 channel scanner might be set up as follows -

Bank  Memory  Frequency
 1      00    145.450
 1      01    145.475
 1      02    145.500
 1      03    145.525
 1      04    145.550
 1      05    145.575
 1      06    -
 1      07    -
 1      08    -
 1      09    -

 2      10    145.600
 2      11    145.612
 2      12    145.625
 2      13    145.637
 2      14    145.650
 2      15    145.662
 2      16    145.675
 2      17    145.687
 2      18    145.700
 2      19    145.712

 3      20    145.725
 3      21    145.737
 3      22    145.750
 3      23    145.762
 3      24    145.775
 3      25    145.787
 3      26    -
 3      27    -
 3      28    -
 3      29    -

 4      30    433.500
 4      31    433.525
 4      32    433.550
 4      33    433.575

Our fictional scanner (probably a Uniden!) would have a row of 10 numbers along the display, and by pressing any of the 10 digit keys the relevant one of the ten banks could be included or excluded from the scan. If the display just shows a little 1 and 4, then banks 1 and 4 are the only ones being scanned. Pressing 4 would make the 4 vanish, and only bank 1 would be included in the scan. Press 4 again (let's call it a Quick Key) and it will reappear and scan those two banks once more.

Simple enough, isn't it? Such a scanner usually allows you to retrieve a given memory directly, no matter where you are. You might be paused (manual mode) on 145.5 but then press some key combination involving 30 and go directly to memory 30 (433.500 in the example above).

Use the scanner often enough and you'll probably end up remembering the channels and contents, and where there are unused gaps you can directly add new finds to. Why do we need more?


By the time you get a new scanner with 2000 memories or more, memory numbers are starting to get awkward. Is a 3 digit memory number much use to anyone? Or 4?!

And note from the above example that memory is allocated to memories 6 to 9 (amongst others) despite them not being used.

Even worse, the 16 channels for 2m repeaters don't fit into one bank of 10 memories, requiring them to be split over banks 2 and 3!

Something has to give....

Dynamic Memory to the rescue!

Having decided that directly numbered memories can be abandoned in the name of progress, Uniden was free to arrange things in a more ordered heirarchy. Much like computers with folders within folders, they decided to arrange the actual 'banks' of memories as 'Groups'. And because having just 10 Quick Keys was going to be a bit limiting, they then arranged for a number of Groups to be collected together as 'Systems'. So a System can have its own Quick Key (to include/exclude it from the scan), and then the Groups within that System can also have their own Quick Keys (selected using a slightly different method) giving a hundred combinations instead of just 10.

Let's see a real world example of how a scanner might be set up, as the best way to see the light is often by gawping at an example.
Having hooked up the scanner to the PC, I've used "Assaf's FreeSCAN" (free software) to download the entire contents of the scanner's memory (saved for safekeeping as a file called Example.996).
Much like similar 'treeviews' in Windows' file explorer and other bits of software, the entire memory of the scanner can be shown on screen with sections-within-sections shown or hidden using the [+] or [-] feature :

FreeSCAN: Example of Systems and Groups in the 'treeview' on the left,
options for the selected System on the right.
(and [CNV] means Conventional System - not trunked)

Many of the System options here can be ignored. You'll only be interested (at first, or on a simpler scanner model) in the System's Name, Quick Key, Delay Time (how many seconds before resuming the scan after the squelch closes) and Hold Time (use 0 seconds to scan each memory in the whole System just once and then move on to the other Systems). Note that I've added the Quick Key numbers to the system names to aid my own memory!

And the actual Groups of channels....

Now we've seen the top level of Systems, let's dig down to the lower level, the Groups within those Systems. Here's an example, showing the list of channels within the Amateur Radio 2m Group:

Different information shown, depending whether a System or Group is selected on the left.

For the Groups, note the most useful setting are the Name and Quick Key. Note from these two screenshots how the Scan Delay is a System setting that affects all Groups within that System. You can't have individual Scan Delay settings for each Group within a System - it's only specified at the top level of the heirarchy in the Systems.

Note that as compensation for missing our old memory numbers, we get the better bonus of being able to name every single channel, as well as the Groups and Systems! There's now no excuse for having a confusing frequency that we forgot why we entered it and what it was for.

Notes on Quick Keys

You can use the same key for two or more Systems, and this will control all those Systems at once with the same key press. Maybe you want something switched with Key 1, which contains a whole System with instant Scan Resume (zero seconds Scan Delay) and another with a 5 second delay.

Quick Keys for Groups within one System are independent from those in other Systems. Each System can have a Group controlled by Key 2 for example, but they all end up switched at different times because you have to select a System before then following that up with the Quick Keys for the Groups :

You have to press the function button, rotate the knob to the system, then (while continuing to press in the function button) you can finally press the group 'Quick Keys' to select the specific choice of groups you require. It's a bit long-winded, and not something I find I'd do lightly, on a whim, chopping and changing every few minutes like you can with the one-press selection of the main Systems themselves.

Systems select : instant. Groups select : painfully awkward enough to irritate!

The only other problem I find is remembering what I've got in my scanner. Every now and then it makes sense to download the whole memory setup to the PC, and make a cheat sheet to use alongside the thing!

Suggestion for Uniden : (if they ever read this!)
- it would really help if, whenever a Quick Key is pressed : the name(s) of the included/excluded System(s) or Group(s) would appear for a second or two (regardless of whether it's scanning or not - it would just replace the scrolling "Scanning" message we normally see). With this new feature, it would be easy to try each Quick Key and see what changes, instead of having to remember what all the numbers mean!

That's it!

So that's all there is to it! Not too bad, was it? We've lost direct memory numbering, but gained Alpha Tags (names) and a memory system that scales up to cope with thousands of memories, neatly arranged - as best we can - into categories that suit us.

And I'm fairly sure that once you get used to backing up to the computer, and adding lots of new channels at the computer followed by a simple upload to put it all into the scanner, you'll wonder why you ever found it daunting. And you'd find it tedious to go back to the old ways.

The flexibility is awesome. You can have totally different scanner setups stored in a number of .996 files, and by uploading different files (wiping what was there before), totally change the purpose of your scanner. And then put it back as it was. Or clone it to/from your friend's scanner. It's so much more versatile than the early days of 16 channel scanners in the 1980s, and by making it so much easier to scan hundreds of channels you'll realise that there is still plenty out there, but you'll only hear it if you actually scan for it! (something that could easily pass you by if you're stuck with an old slow scanner covering only 20 channels per second where you only scan the same old 30 channels and wonder why you never hear much!)

Further reading on this here website -

Using FreeSCAN to easily enter lots of sets of Nationwide Channels

My Uniden USC230-E review has another go at summing up the Dynamic Memory System, and more information about hooking it up to the PC, plus lots lots more.

If this explanation has helped you, it would be nice to hear from you. Any further info or questions are welcome! Please leave a message on the board at - thanks.

First written January 2013. When I last typed here it was 15 Jan 2013.

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