[TenTec] Omni VII Digital

[Bob McGraw - K4TAX]

Someone asked about "what's a value of -60dB in terms of voltage?"

Well if I did the math correct:

- 60 dBv = 0.001 volts or 1 millivolt
-30 dBv  = 0.031 volts or 31 millivolts
-20 dBv = 0.100 volts or 100 millivolts
+20 dBv = 10.0 volts

73
Bob, K4TAX



----- Original Message ----- 
From: "Robert" <rmcgraw at blomand.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Tuesday, August 12, 2014 9:20 AM
Subject: Re: [TenTec] Omni VII Digital


> Louis brings up a good point on audio levels.  There are 3 basic audio 
> level groups.
>
> They are:
> (a) MIC level typically -60 dB to - 30 dB
> (b) Line level typically -20 dB to +20 dB
> (c) Speaker level - usually several volts depending on power in watts and 
> impedance.
>
> Thus the levels ranges of (a), (b) and (c) should not be expected to be 
> connected directly, one to another, without some specific means to correct 
> levels to the proper range.
>
> Thus  connecting a speaker level output direct to a mike input can damage 
> the mike input components. And the same for speaker output level to a line 
> input.
>
> Don't worry about "matching impedances" as systems today operate as 
> voltage sources and loads.   Except when using power amps driving speakers 
> to attain efficient transfer of power.
>
> Plus interconnecting levels of the same range will assure the best 
> Signal-to-Noise ratio.
>
> Interface devices such as the Tentec 712 USB Soundcard interface or the 
> SignaLink USB interface are good choices to interconnect systems and 
> levels.
>
> 73
> Bob K4TAX
>
> Sent from my iPhone
>
>> On Aug 12, 2014, at 8:53 AM, Louis Ciotti <lciotti1 at gmail.com> wrote:
>>
>>
>> BLACK = pin 3, push to talk
>> Ground from the 46176 cable is connected to pin 2.
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