Good set of results from last night Roelof !
8 bit AD , seam's to be various lines on this , but the 8 bits is the
resolution against a reference , if the ref is , say 1 volt and the
wanted is 2 volts , then you have , 256 steps ~ 4 mV per step 1
volt to 20 , then the steps are ~ 40 mV etc , I'm not sure , hard
numbers are directly related to in use performance , as the control
software has a role to play ... along with circuit design
I live close to a 10k MW tx , and the RTL dongle on 80/60 meters ,
gives a cleaner Rx than the ft897d from the same Ae , the skanti
r5000 , needs a band pass filter to stop cross modulation and the
racal 6790gm , no pre amp , has no issues , but deploys 5 to 7 watts
Rf drive to the first mixer ..
to give about 120 dB dynamic range .
73-Graham
G0NBD
--------------------------------------------------
From: "Roelof Bakker" <[email protected]>
Sent: Saturday, April 15, 2017 11:09 AM
To: <[email protected]>; <[email protected]>
Subject: Re: LF: Re: [rsgb_lf_group] VO1NA 477 OP8 :Start 2300 finish
0900 50 watts to monopole.
Hello Joe,
Attached your OP8 signal as received here last night on a Afedri SDR
and mini-whip antenna. At it strongest I had aural copy.
You probably have seen my reports on your Opera window.
These were received using a 20 dollar RTL-SDR V3 in direct sampling
mode under SDR#. Dispite the only 8 bit ADC, it looks that it can be
pressed in service when you use proper front end filtering.
If I am correct, an 8 bit ADC can provide a dynamic range of about
50 dB. This is not much when compared with e.g. a PERSEUS which
provides a dynamic range short of 100 dB. The question is how much
dynamic range you really need in practice.
The famous Drake R4C has, as measured by Sherwood, a dynamic range
of just 58 dB. Due to an excellent pre-selector it is a nice
receiver.
Anyway, I am very pleased with the result.
73,
Roelof, pa0rdt
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