BCD396T sensitivity measurements

[mancow]

I was bored and decided to do some testing of my 396 after all the recent discussion of the lack of sensitivity of this unit in various threads.

This is in no way professional or even an ideal test setup. It's just me in the garage keeping myself busy but here it goes.

Test set: IFR1900CSA 100khz-2.1Ghz capability
Radio: BCD396T
serial# 328Z5400077XX (XX left out)
On battery only at 3.77 volts

Measurements taken from monitor in micro volt setting not dBm

First number is Mhz, Second is voltage to open squelch, Third is voltage to close squelch. Voltage levels are micro volts

130Mhz .273, .207
140Mhz .240, .203
150Mhz .260, .216
160Mhz .275, .216
170Mhz .275, .241

418Mhz .525, .300

440Mhz .525, .320

460Mhz .550, .340

866Mhz .476, .300

1293Mhz .475, .280

S Meter votage at each step at 155 Mhz:

micro volts

S1= 1.2
S2= 2.16
S3= 3.99
S4= 6.020

 

[K7TKR]

Just curious-what do your results tell you other then provide a set of numbers? What's the releventcy?

 

[mancow]

From what I've compared with other units it's on the deaf side. However, those super hot receivers like the AOR8000 suffer so much from interference that it offsets the advantage.

Next, I'll test the Astro Saber Vhf and some other commercial stuff for comparison.

 

[DaveIN]

I was bored and decided to do some testing of my 396 after all the recent discussion of the lack of sensitivity of this unit in various threads.

This is in no way professional or even an ideal test setup. It's just me in the garage keeping myself busy but here it goes.

Test set: IFR1900CSA 100khz-2.1Ghz capability
Radio: BCD396T
serial# 328Z5400077XX (XX left out)
On battery only at 3.77 volts

Measurements taken from monitor in micro volt setting not dBm

First number is Mhz, Second is voltage to open squelch, Third is voltage to close squelch. Voltage levels are micro volts

130Mhz .273, .207
140Mhz .240, .203
150Mhz .260, .216
160Mhz .275, .216
170Mhz .275, .241

418Mhz .525, .300

440Mhz .525, .320

460Mhz .550, .340

866Mhz .476, .300

1293Mhz .475, .280

S Meter votage at each step at 155 Mhz:

micro volts

S1= 1.2
S2= 2.16
S3= 3.99
S4= 6.020

You should add your findings to the Wiki. Nice work.

 

[UPMan]

Interesting measurements, but they should be labeled "Squelch Threshold" measurements, not sensitivity. Squelch Threshold is a valid parameter to measure, but is more related to the setting of internal voltage comparators than the base sensitivity of the receiver. Sensitivity measurements are normally measured with squelch fully open to begin with...

Quoting from an on-line article:

Sensitivity is commonly defined as the smallest RF signal that can produce a usable baseband output from a receiver -- the key word being usable. When testing the analog radio, you determine what is a usable level via a sinad ratio. For instance, the 12dB sinad test refers to the RF level required to reduce the open squelch distortion by 12dB when a 1kHz tone is injected (typically a level of 0.35mV). Any level below this would not produce a usable baseband output.

Here is a great white paper on SINAD and how it is used to determine various performance metrics: http://www.aeroflex.com/products/signalsources/signalgens/appnotes/885.pdf

and another article explaining how to measure sensitivity:
http://www.radio-electronics.com/info/receivers/sensitivity/sinad.php

 

[mancow]

I agree, I should have called it that to begin with.

Although other receivers I have will unsquelch with cleaner audio at lower levels I find the 396 to be more useable overall. My Icom R20 is a good example. It's so sensitive everything gets through. Normal signals are splattered across 15 khz if there is any power to them at all. It's basically useless for unattended searching.

I can leave the 396 to do it's job all day and never worry. It just works. I reminds me more of a Motorola unit than a consumer grade product.

 

[bwigg]

I just made a quick check on VHF 154.370 mhz with my BC396. Senstivity measured .285 uv @ 12db sinad with open squelch. Squelch breaks right about the 12 db Sinad setting when set to 1. So it looks like my VHF senstivity measured about the same as yours. I used standard width FM instead of narrow FM. I think narrow FM mode is for 12.5 khz channels which are limited to +/- 2.5 khz of deviation. I used the standard test of 1 khz tone deviated at +/-3 khz. My testing used 12 db quieting as obtained on the built in SINAD function in my Motorola R2001D service monitor.

 

[wabc770]

From what I've compared with other units it's on the deaf side

Shucks. I'm researching what to buy to upgrade from my Pro92B which I consider to be
kinda deaf.

The 396T is at the top of my list -- this is rather unsettling to hear. I'd hate to spend
$5xx dollars to wind up where I am now.

 

[Dewey]

Shucks. I'm researching what to buy to upgrade from my Pro92B which I consider to be
kinda deaf.

I regularly refer to my Pro-92B when talking about my dislike for the 396's lack of sensitivity (http://www.radioreference.com/forums/showthread.php?t=38184). As a matter of fact, I think I have compared the 396 to my 92B in all of the sensitivity threads that I have participated in. Bottom line, the 92B is the only one of my many scanners that is less sensitive than the 396 when using portable antennas. However, I think that I am finally adjusting to the 396's not-so-good sensitivity, and have accepted it since it is not as bad as the 92b .

Dewey

 

[wabc770]

I regularly refer to my Pro-92B when talking about my dislike for the 396's lack of sensitivity (http://www.radioreference.com/forums/showthread.php?t=38184). However, I think that I am finally adjusting to the 396's not-so-good sensitivity, and have accepted it since it is not as bad as the 92b .

Thanks for pointing me towards a very interesting thread, Dewey.

I'd hate to think I'd buy a 396 and wind up, like with my 92B, grabbing my little
Pro-83 because it's the one that can best hear what I wish to monitor.

It's especially a downer to hear of possible 396 performance shortcomings in light
of ALL those features it has!!

It's not that I've got a big feature-fetish, but the 396 appears to have, at least
on paper, a slew of features which look to be really useful.

Granted, priority channels, for example, sound useful in theory, but I find myself rarely using one because the audio dropouts every couple of seconds drive me batty and makes my eyes go cross.

And I don't use the Signal Stalker on my 83 quite as much as I thought I would, partly because of that - tho it can be used while not scanning - and partly cuz it just doesn't seem to find very much. It's still a nice feature however!

And stuff like wx/same alerts are something I never use. When it gets stormy
around here, that's when I love tuning around the most to hear the higher level
of activity. I usually hear alerts via skywarn minutes ahead of their actual release from the NWS anyway.

It just boils down to wanting raw performance first and foremost I guess at this point.
Hopefully I'll get a chance to see/hear a 396 in use before I decide on which
way to go.

Until then, the input here is most welcome and valuable. I appreciate it!

Thanks -- and hope ya'll are having/did have a Festive 4th!

 

[302HO]

Okay.......let me ask ya something.


If the 396 is kinda weak on reception, would a person be better off with getting a 296D?


Please excuse the newby type question......i am a newby.

thanks.