[TenTec] Omni VII Digital

[Carl Moreschi]

0 DBM is defined as 1 milliwatt.

At 50 ohms, that's 0.22 volts for 0 dbm.

S9 is -73 dbm so 0 dbm is S9+73.

-10 dbm is .1 milliwatt.
-20 dbm is .01 milliwatt
-30 dbm is .001 milliwatt
-40 dbm is .0001 milliwatt
-50 dbm is .00001 milliwatt
-60 dbm is .000001 milliwatt

at 50 ohms, -60 dbm is .007 volts or 7 millivolts.

Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com

On 8/12/2014 9:06 PM, Bob McGraw - K4TAX wrote:
> 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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>
>
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