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Old 09-15-2018, 10:50 PM
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Default Icom R-8600 / Anomalies

An "anomaly" is generally defined as:

a) something that deviates from what is standard, normal, or expected
b) an oddity, peculiarity, abnormality, irregularity, inconsistency, quirk

I want to focus this thread on anomalies which I and others have discovered on the Icom R8600 receiver. Indeed, the is a very complex and sophisticated monitoring tool. But as I have discovered, there are certain peculiarities associated with the operation of the receiver which come into play, and once discovered, can add to the flexibility of the unit during certain operating conditions.

I would hope that others who discover unusual or unexpected behavior with the R8600 will also help by contributing their observations to this thread.

With that in mind, let me present:

Mike's Icom R8600 Anomaly # 1

Interesting tuning step variations come into play when using the "Programmable Tuning Step" function, as described in section 3-3 of the R8600 Instruction Manual.

The best way to demonstrate/describe this anomaly is to give a brief description of the occurrence and then instructions on how to observe this on your own R8600.

Here in New York City, the Police Department operates in the "T" band, on what were once considered "spilt" frequencies. (These days, the "splits" of frequencies have become even more narrow, but that is not particularly germane to this demonstration.)

The NYPD's main dispatch frequencies operate 25 KHz apart, but on "Odd" frequencies. They start at 476.31250 and range up to 477.13750.

In order to demonstrate this "anomaly":

1) use the F-INP (Frequency Input screen) to manually program in 476.31250 in FM mode
2) On the Tuning Step screen, select the "standard" (not custom) 25 KHz step.
3) When you start to manually tune, you will see the radio jumps to 476.32500, then 476.35000, etc, thus "rounding off" and missing the "splits". Bummer.
4) Now, got back to the Tuning Step screen, and select the Programmable Tuning Step function to set up a 25 KHz step. (The custom step is turned on when you see the background area of that function turn blue in color.)
5) You must, once again, manually enter 476.31250 on the Frequency Input screen.
6) Manually start tuning again and wow, neato--- with the Programmable Tuning Step engaged, you are now hitting all the correct "splits"--- 476.31250, 476.33750, etc. The radio is not "rounding off", as it does with the standard 25 KHz split.

It appears that you must always manually enter the starting frequency via the Frequency Input screen for this little trick to work.

This can be a useful function during manual tuning, or "searching" to hit only certain frequencies within a range. It demonstrates one of what are likely dozens (or perhaps even hundreds) of operational variations in the R8600, which make it such a flexible and powerful monitoring tool.

I have not experimented with the operation of other "standard" vs "programmable" tuning steps-- I will leave that to others to explore or discover.

I hope those here on the forums who discover unusual operational behaviors in the R8600 will contribute to this thread. One interesting sidenote is that these "undocumented" features could inadvertently be eliminated with future firmware upgrades. That's why I feel that it is so important to document as many of these anomalies as we find.

Last edited by MStep; 09-15-2018 at 11:00 PM..
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Old 09-16-2018, 5:38 AM
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More testing has produced two footnotes to the above procedures:

1) If you are in the 25 KHz standard step, and punch up 476.31250 into the "Frequency Input screen", the unit may yield the correct "split" steps, although some operations will place you back onto the rounded-off frequencies.

2) The same applies if you are programming in a "search" function, as long a you to make sure the "start" frequency is input correctly (in this case, 476.31250), so that the proper split steps will be achieved.

Obviously, I used frequencies that are in use in my own area to experiment, but this should be applicable to other similar types of split frequencies in use around the bands.

I imagine that as other users experiment with various step functions, other interesting results may be achieved.
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Old 09-18-2018, 1:04 AM
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Mike's Icom R8600 Anomaly # 2

The second anomaly seems to be more of an operational misunderstanding of terminology, perhaps on Icom's part. A quick press of Dial "A" presents us with "Resume Time" as one of the options. On the R8600, this is the time the radio waits after a transmission completes before it resumes scanning. Those options are zero to five seconds, and then "Hold".

On most other radios, "Hold" is the equivalent of infinity, meaning that once the radio stops on that channel/frequency, scanning (or searching) will stop and stay on that channel until manually resumed. Not so on the R8600. The "Hold" function simply extends the Pause time to approximately 20 seconds, and then the scanner resumes.

In order to achieve "Affinity" (Stop Scan), one has to give Dial "A" a long (as opposed to short) press, and then we are presented with a "Scan Resume" menu., Choices are OFF or ON. If scan resume is "ON", scanner follows the timing set by the "Resume Time' function. If the option selected is "OFF", then the scanner enters infinity mode, and scanning (or searching) will stop when a signal is received until manually resumed by the user.

(For those not confused enough already, simply turning Dial "A" without pressing sets the "Pause Time". Typically, on most other scanners, that would be the equivalent of the Resume Time menu on the 8600. In fact, on the R8600, this actually sets a "DWELL" time-- even if a transmission is still in progress, the unit will begin scanning as soon as the dwell time is achieved. Choices are from one to thirty seconds and HOLD. In this menu, HOLD is equal to setting no dwell time, and letting the transmission complete before scanning resumes.)

Icom has added an addendum type sheet to the manual attempting to clarify some of these functions, but I think they missed the mark, so to speak. In effect, most seasoned scanner enthusiasts will note that Icom simply switched the terms of "Pause" and "Resume" from standard scanner nomenclature, thus confusing some users.

These are all very powerful functions in the radio's arsenal of great features. All of this information is based on Firmware version 1.33 -- some of these options could change in future versions.
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Old 09-18-2018, 3:07 PM
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Very useful and great to know this - I wasn't clear on the programmable tuning step and was indeed missing the 'correct' freqs in a few places, Much appreciated!
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