10479Re: [perseus_SDR] PERSEUS sensitivity
- Jul 1, 2010Hi Roelof,
interesting data. Some week ago I did several days of activity in 10m
in WSPR. My antenna is a seven-band vertical (ECO 7+) so obviously
Checking at various times of the day, I have been always able to
detect an increase in noise by switching from a 50 ohm termination to
the antenna; so the Perseus seems sensitive enough for operation in
suburban areas (I live in a residential village, but every house
seems to have three PC and three plasma TVs, not counting LED lightnings :-()
However it seems that other stations receive my signal with better
S/N, so other places are clearly quieter. I did some experiment with
a nice Norton differential amplifier, low noise (3 dB NF) and 10 dB
gain (an ANZAC AM-109) and put it before Perseus. The S/N indeed is
now marginally better, let say 3 dB in average. However, the AM-109
dissipates about 10W... :-) linearity and low noise have a price!
73 - Marco IK1ODO - JN35sa
At 18:18 01-07-10, you wrote:
>On paper the 16 dB noise figure of PERSEUS is something that looks a bit
>As I understand it, this is a design trade off to maintain the good strong
>signal handling capabilities of the A/D convertor at the receiver front
>However, how "bad" is it in practice?
>Here you can download a 42.6 MB PERSEUS recording:
>It is a 400 kHz wide recording tuned to the 500 milliwatt (!) beacon
>signal of Aldo Moroni, IW2DZX from Italy as received in the Netherlands.
>You can also tune around and see what a nice tool PERSEUS waterfall
>display is to spot the fast fading in and out 28 MHz beacon stations.
>My antenna is a 2 x 16 m long doublet with 11 meter open feedline, matched
>with a balanced ATU.
>Roelof Bakker, pa0rdt
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