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TRX-1: GREAT airband audio!

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#1
Wow - I wasn't expecting this out of my new toy....

The AM demodulation and fidelity of the audio for airband monitoring from a speaker the size of a quarter is a total surprise.

Plenty of volume, although no, I would not expect to hear it on the flightline. :)

I'm hearing much more *detail* in pilots voices that make it a real pleasure to listen to as compared to my older scanners. Now if we could just put TWO of those speakers side by side in the case!

The lack of any squelched speaker hiss from the front speaker and also the headphone jack is also very appreciated.

So far so good!
 

tumegpc

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#2
Wow - I wasn't expecting this out of my new toy....

The AM demodulation and fidelity of the audio for airband monitoring from a speaker the size of a quarter is a total surprise.

Plenty of volume, although no, I would not expect to hear it on the flightline. :)

I'm hearing much more *detail* in pilots voices that make it a real pleasure to listen to as compared to my older scanners. Now if we could just put TWO of those speakers side by side in the case!

The lack of any squelched speaker hiss from the front speaker and also the headphone jack is also very appreciated.

So far so good!
Another plus for Whistler scanners.
 
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#3
I wish I was as happy as you. I live in Italy and, (being an absolute beginner in scanning) I find it very hard to use in Italy. What can I do (besides selling it)? Please give me some ideas or links
Thanks
 
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#4
Yep - even though the speaker is small, and obviously doesn't produce very low frequencies, what it does produce seems very clean. Much cleaner than my old Pro-106 / GRE 300/800 and the later 1040.

So something in the audio chain got improved, unless the speaker is masking it. :)

I'm not sure, but it is sounds almost dsp-based, like a SiLabs chip used in the later model CCranes's which I love.

Thing is, it doesn't matter how many features a scanner has, if the audio is so poor that it offends the ear, or causes long-term fatigue. So far I'm happy. Make it sound like a Motorola and I'll buy FIVE of them hands down, sight unseen. :)

spijkersoop: the TRX-1 can be a handful for a first-timer. But you've come to the right site for help. Perhaps hang on to it, and start with a simpler unit (based on your needs), then you'll have something to upgrade to immediately!

Perhaps the European sub-forum can help too right off the bat:

https://forums.radioreference.com/europe-radio-discussion-forum/

Hang in there - it becomes easier over time...
 

hypersight

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#5
Hertzian - On the airband, do find that the first few milliseconds gets cut off on each transmission? My TRX 2 does that. I usually miss half of the first word spoken. I have it set to AM (as opposed to auto) and my squelch is at the very minimum I can get it before the "white noise" stays open.
 
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#6
I had a TRX1 and I sold it and got the SDS100, I should have kept the Whistler!
Airband is 100 percent better on the TRX1 that and VHF and UHF too as far as clear audio and sensitivity.
I'm kicking myself in the pants.....
 
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#7
Hard to say since I don't own a TRX-2. However ....

I have noticed that some *extremely* strong signals, the agc might be cutting off that first syllable. Maybe - just a guess. By strong I mean the planes that are on ILS approach directly above me, and can be heard with no antenna at all.

Try it with no agc, and maybe with the attenuator on, unless it kills your reception. I don't know what your environment is like, so maybe some underlying noise / desense is contributing to the issue?

All conjecture at this distance, and it has to be super extreme for me to notice that - and not on all planes either.

Sidenote: I mention this often, but I use a special duck that is very NARROW banded for GA monitoring with most of my scanners: The Icom FA-B02AR. Used on their transceiver line, so you get them at pilot shops, or FBO counters sometimes. Unlike most scanner related antennas, this thing is super narrow banded, and really helps tame the front end. Just thought I'd mention it because to me, with scanner front-ends, that thing is worth it's weight in gold.

Not good for listening to anything else because of it's narrow nature. Which is GOOD if you are specializing in airband vhf monitoring. I've used them on quickie roll up window mounts too when mobile. Stiff enough to survive for awhile in the wind. :)
 
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#8
hypersight - now you have me wondering about something....

Other than the usual suspects like
1) Are you scanning a long scanlist - it takes time to come around
2) Are you just monitoring / paused?
3) Do you have a priority check happening?

While I haven't noticed it much, I wasn't looking for the issue. Brought back a concern waaay back when I was using scanners that had a built-in battery-saver and no way to defeat it!

When monitoring a single frequency, on a scanner using a default battery saver (actually monitoring packet radio decodes back in the day), the solution was to put two identical freqs (objects for us now) in the same scanlist, and scan. That defeated any battery save.

I can't find an optionin the manuals for battery save, so I'll ask if maybe there's a tiny one, like a .2 ratio on by default when paused. Not necessary for a TRX-2, but I'll ask anyway....
 
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#9
It's the mute function of the audio amplifier that is the problem. It is very slow of unmuting the audio so that you miss the first 1/2 second. In the recordings you do not miss anything, instead it unmutes too early so you record a noise burst before an analog non-subtone carrier are received. Probably needed to compensate for slow action with subtones and digital decoding.

You can actully hear the loudspeaker audio rising slowly to full volume during the first couple of milliseconds and it is not like other scanners that you have a distinct on/off type of click.

Of course you notice this only on transmissions that do not have a constant carrier, like in the airband and marine frequencies.

/Ubbe
 

hypersight

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#10
hypersight - now you have me wondering about something....

Other than the usual suspects like
1) Are you scanning a long scanlist - it takes time to come around
2) Are you just monitoring / paused?
3) Do you have a priority check happening?

While I haven't noticed it much, I wasn't looking for the issue. Brought back a concern waaay back when I was using scanners that had a built-in battery-saver and no way to defeat it!

When monitoring a single frequency, on a scanner using a default battery saver (actually monitoring packet radio decodes back in the day), the solution was to put two identical freqs (objects for us now) in the same scanlist, and scan. That defeated any battery save.

I can't find an optionin the manuals for battery save, so I'll ask if maybe there's a tiny one, like a .2 ratio on by default when paused. Not necessary for a TRX-2, but I'll ask anyway....

Hi Hertzian.
To answer your questions
1. My airband scanlist is quite small. It just 12 frequencies for my airport.
2. This delay happens when the scanner is paused.
3. No PRI check on at all.
 

hypersight

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#11
It's the mute function of the audio amplifier that is the problem. It is very slow of unmuting the audio so that you miss the first 1/2 second. In the recordings you do not miss anything, instead it unmutes too early so you record a noise burst before an analog non-subtone carrier are received. Probably needed to compensate for slow action with subtones and digital decoding.

You can actully hear the loudspeaker audio rising slowly to full volume during the first couple of milliseconds and it is not like other scanners that you have a distinct on/off type of click.

Of course you notice this only on transmissions that do not have a constant carrier, like in the airband and marine frequencies.

/Ubbe

Ah ok. Well that makes sense. I guess there is not a lot that can be done about that since it is a hardware issue.
Thank you Ubbe!
 
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#12
..... 2. This delay happens when the scanner is paused. ...
Ah, ok. I guess I didn't notice it on my end. I'm running the latest cpu / firmware, but perhaps I'm not listening critically enough.

Good info from Ubbe! Maybe there is something that can be done about that?

In the meantime, have you tried duplicating an airband object into a sole scanlist, and scanning both of the same freqs to see if it makes any difference?

It would be interesting if that old trick still works...
 
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#13
The slow unmute and terrible squelch action and changing pre-filter components to be able to properly receive 68-88MHz in non-us countries and change attenuator from a 20dB to a more usable 10dB function are pretty much impossible to modify without a schematics to look at. And also the components used are of the super micro type that you'll need a micoscope to be able to operate on them.

/Ubbe
 
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#15
Um, ok. I wouldn't call it terrible at all. I don't really notice it in operation. I guess most of the pilots around me don't quick-key the mic.

If for some reason I am monitoring so closely that I'm going to miss the first letter of a tail-designator from a quick-keyer, I'll use something other than a scanner. :)

In other words, not a show-stopper issue.

But maybe if we ask nicely, there *might* be something Whistler can do about the AM audio agc speed. One never knows.
 
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#16
I asked them 18 months ago. They have done the recording function so that it uses a very strong AGC action that works on top of the normal audio AGC on a channel so it becomes over exaggerated in the recordings. They also have no high pass filter to cut off CTCSS tones that now totally dominate the audio in the recordings. It also seems that CTCSS search only are active a short time when a carrier starts and then are locked and used for the rest of the carrier time.

/Ubbe
 
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#17
Um, ok. I wouldn't call it terrible at all. I don't really notice it in operation. I guess most of the pilots around me don't quick-key the mic.
The terrible squelch action are that it opens first on a very strong signal and closes on a very weak signal, a too high hysteres, so that you cannot set it to decode digital signals that are not fully saturated, that have just a small amount of noise.

In the 420MHz band the level where the squelch open and closes are 4-9 in FM mode and 5-8 in NFM mode and as NFM have less signal/noise ratio it seems to work as designed but using a 460MHz frequency programmed to a channel it is the same 3-7 level for both FM and NFM. The noise level in the audio are considerable higher in NFM so I guess the firmware are only doing an audio level adjustment but keeping the FM IF filter and not switching to the NFM IF filter as it should. Whistler doesn't seem to have any quality control over the firmware. Whenever a feature are added or changed something else goes agurk.

/Ubbe
 
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#18
They also have no high pass filter to cut off CTCSS tones that now totally dominate the audio in the recordings. It also seems that CTCSS search only are active a short time when a carrier starts and then are locked and used for the rest of the carrier time.
I noticed the lack of high-pass filtering pl tones right away when using earbuds and headphones. I can't use the earphone jack for earphones under those conditions.

Which is surprising, since I'd say a large number of the buying demographic are amateur radio ops, who yes, still listen to amateur systems and even other commercial systems running CTCSS on the output. Hard to listen.

Then again, Uniden's CRS clock radio scanner (which I used for some small mil-air monitirong) had the very same issue for conventional fm too with the external audio output. I don't know why scanner companies miss this. Somebody, somewhere, in the corporation(s) actually listens to their product right? Sometimes I wonder.

I'll keep an eye out for the CTCSS discovery thing. That's a bummer if that doesn't work right, because to me a scanner is not just for entertainment - I put it to use as a *tool* for some other radio system interference puzzles etc.
 
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#19
We're kinda' getting way far away from airband audio now, but I formally filed the following as "feature requests" :

1) Hi pass earphone audio filter to attenuate CTCSS tones.

2) MDC signalling tone mute option. Unless there is full decoding of MDC signalling, once the novelty of hearing MDC signalling tones on transmissions wears off, it is just super-annoying. Muting these would be an AWESOME feature. Unless of course one wants to be a wanna-be safety official, which many don't understand -- THEY don't hear these tones on THEIR radios!

I stopped there, but was tempted to add REVERSE BURST. Didn't want to push my luck. :)

I'm hoping that somewhere in the dsp or elsewhere these can be incoporated. Fingers crossed!
 
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#20
To iar band listeners:
My main radio is the TRX-1 but I have the say, the little BC-125AT handheld is incredible for planes. Affordable, too.
 
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