TRX-2 Performamce on 70-87MHz
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Ubbe
Member
The front-end filter isn't designed for that frequency range so it starts to attenuate at 70MHz and at 87MHz it is really bad like a mV in sensitivity or similar. I hear 25W mobile transmitters at 85MHz 2-3km from home, that's the maximum range, the same as I have on PMR446 0,5W.
/Ubbe
/Ubbe
Valeriy
Member
Then the TRX-2 manual is wrong.
On Page 71, Frequency Coverage, there is a gap between 54 MHz and 108 MHz:
[...]
49.835-54.000 MHz.......................................(in 5 kHz steps/FM)
108.000-136.9916 MHz.........................(in 8.33 kHz steps/AM)
[...]
The same is true for all the manuals of RadioShack, GRE Com and other Whistler scanners I have seen...
On Page 71, Frequency Coverage, there is a gap between 54 MHz and 108 MHz:
[...]
49.835-54.000 MHz.......................................(in 5 kHz steps/FM)
108.000-136.9916 MHz.........................(in 8.33 kHz steps/AM)
[...]
The same is true for all the manuals of RadioShack, GRE Com and other Whistler scanners I have seen...
Ubbe
Member
It is not an official frequency range that Whistler opened up, as it is not hardware supported and performs so poorly, but they where kind enough to let us have at least some kind of monitoring in that range. Kudos to Whistler for doing that.
TRX-2
54MHz = 0,25uV -119dBm
64MHz = 0,90uV
74Mhz = 5uV
84MHz = 7uV
86Mhz = 25uV
87MHz = 60uV -71dBm
145-173MHz = 0,25uV
420-470Mhz = 0,4uV
806Mhz = 0,35uV
906Mhz = 0,3uV
Uniden BCD536HP
54MHz = 0,25uV
59MHz = 0,25uV
60-906Mhz = 0,20uV
The TRX-2 have squelch problems. The more the SQ are turned up, the more noise are added to the audio. With the SQ at 0 there's normal audio and with each step up to MAX the noise in the audio increases and are real bad at MAX setting. It also sounds as if the high frequency treble in the audio are reduced the same amount so it has a muffled bassy sound at MAX squelch setting. The whole squelch functionality are terrible designed by Whistler as it is difficult to set a level that works well at both open and closing of the SQ and for both analog and digital modes.
/Ubbe
TRX-2
54MHz = 0,25uV -119dBm
64MHz = 0,90uV
74Mhz = 5uV
84MHz = 7uV
86Mhz = 25uV
87MHz = 60uV -71dBm
145-173MHz = 0,25uV
420-470Mhz = 0,4uV
806Mhz = 0,35uV
906Mhz = 0,3uV
Uniden BCD536HP
54MHz = 0,25uV
59MHz = 0,25uV
60-906Mhz = 0,20uV
The TRX-2 have squelch problems. The more the SQ are turned up, the more noise are added to the audio. With the SQ at 0 there's normal audio and with each step up to MAX the noise in the audio increases and are real bad at MAX setting. It also sounds as if the high frequency treble in the audio are reduced the same amount so it has a muffled bassy sound at MAX squelch setting. The whole squelch functionality are terrible designed by Whistler as it is difficult to set a level that works well at both open and closing of the SQ and for both analog and digital modes.
/Ubbe
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[QUOTE="Ubbe, post: 3059551, member: 86563"
The TRX-2 have squelch problems. The more the SQ are turned up, the more noise are added to the audio. With the SQ at 0 there's normal audio and with each step up to MAX the noise in the audio increases and are real bad at MAX setting. It also sounds as if the high frequency treble in the audio are reduced the same amount so it has a muffled bassy sound at MAX squelch setting. The whole squelch functionality are terrible designed by Whistler as it is difficult to set a level that works well at both open and closing of the SQ and for both analog and digital modes.
/Ubbe[/QUOTE]
I am thinking you might have a defective unit, Ubbe. I have both TRX radios as well as the 1088, and the squelch does not affect the audio on my radios, only the signal threshold. Easily tested while listening to a weak weather broadcast in the 162.40 range here in the US. No change with the audio but it does cut out when I turn the squelch all the way CW.
Bob
The TRX-2 have squelch problems. The more the SQ are turned up, the more noise are added to the audio. With the SQ at 0 there's normal audio and with each step up to MAX the noise in the audio increases and are real bad at MAX setting. It also sounds as if the high frequency treble in the audio are reduced the same amount so it has a muffled bassy sound at MAX squelch setting. The whole squelch functionality are terrible designed by Whistler as it is difficult to set a level that works well at both open and closing of the SQ and for both analog and digital modes.
/Ubbe[/QUOTE]
I am thinking you might have a defective unit, Ubbe. I have both TRX radios as well as the 1088, and the squelch does not affect the audio on my radios, only the signal threshold. Easily tested while listening to a weak weather broadcast in the 162.40 range here in the US. No change with the audio but it does cut out when I turn the squelch all the way CW.
Bob
Project25_MASTR
TX-COMU
Can't say I've ever had any squelch problems with mine (granted I only use it occasionally).
I will mention, they spec'd all of those sensitivity levels for 5 kHz deviation. Not 2.5 kHz deviation (which in my testing, resulted in about 5-6 dB less sensitivity to narrowband).
Ubbe
Member
The measurements are my values from my own scanners.
Listen to a silent carrier with the TRX-2 that are strong enough that the SQ doesn't close when set at MAX. While listening to the audio turn up the squelch from 0 up to MAX and my TRX-2 sounds as if the carrier are not at full strenght due to the added noise to the audio. I had the modulation of the signalgenerator set to a low value and the 1Khz tone level didn't change from the loudspeaker so the AGC doesn't seem to be involved. It's really strange as the SQ level shouldn't have anything to do with the audio quality.
/Ubbe
Listen to a silent carrier with the TRX-2 that are strong enough that the SQ doesn't close when set at MAX. While listening to the audio turn up the squelch from 0 up to MAX and my TRX-2 sounds as if the carrier are not at full strenght due to the added noise to the audio. I had the modulation of the signalgenerator set to a low value and the 1Khz tone level didn't change from the loudspeaker so the AGC doesn't seem to be involved. It's really strange as the SQ level shouldn't have anything to do with the audio quality.
/Ubbe
Project25_MASTR
TX-COMU
I’ll check it out next time I have the R2670 and TRX-2 out at the same time. I’ll see about retesting for 12 dB SINAD.
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Valeriy
Member
That sounds interesting, I didn't know of such a thing before, thank you.
The official data regarding the 436 are close to the above, but only on the paper:
53.980 MHz 0.3 μV
72.515 MHz 0.3 μV
The 436 actually performs poorly in VHF Low band (and in UHF, too).
It performs rather well only in VHF High band...
Back on topic: is it possible to test in VHF Low band also other Whistler scanners (as well as the previous GRE Com and RadioShack models) or
has that feature been enabled only in the TRX-2?
Project25_MASTR
TX-COMU
Standard SINAD test performed by generating a -47 dBm 1000 Hz tone on the frequency of interest at the deviation of interest setting audio to 50% max rated, and then adjusting the signal level until an average reading of 12 dB SINAD is obtained. You take your readings off the speaker output (have to isolate Motorola mobiles with an isolation transformer). The volume setting is really to get a clean reading if there is added distortion in the audio amp as SINAD can also be tested at line levels. In other words, analog AM/FM and SSB radios can be tested for analog receive sensitivity using actual radio service equipment such as a Signal Generator and SINAD meter or Service Monitor.
When I did my tests I did note some approximate P25 5% BER tests which were taken by using a radio that is actually capable of performing the test to get the signal level, then creating a 1011 Hz test pattern with a service monitor and using the reproduced audio as a reference since the TRX does not have any kind of service menu to display 5% BER. Be a nice feature for Whistler to add IMO but for a consumer product…likely will never see it happen.
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Wil-lee
Member
My new TRX-2 has such noisy distorted audio quality I am returning it as defective.
Hope my replacement unit does not have the same problem.
None of my other scanners have any noise or distortion and sound nice and clear on any antenna.
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