[R-390] r390a and SDR

[jm]

Hi Larry

Many thanks for your answer. Sorry that I'm not very familiar with the
terms. I think thas it's called the noise floor. In my layman words the
place where the signal begins. I have checked different sdr receivers and
the point (I suppose the noise floor?) where the signal appears is
different. For example in the sdrplay the figure is -90 db. In the case of
the combination Funcube/r390 is -100db. My doubt is whether that figure of
-100db corresponds to the sdr receiver of to the 390.  I am not sure if my
explanation now is clear enough.

Thanks

El vie., 19 abr. 2019 a las 5:53, Larry H (<larry41gm at gmail.com>) escribió:

> Hi Jose,  In reference to increasing the bandwidth, it might be possible
> to increase it to 50 or 60 kh, but I doubt any more than that.  In order to
> do that, you would need to bypass the 16 kh filter in the IF deck.  You
> would also need to put a custom filter in it's place to increase the gain
> of the skirts, so the result would be some what flat.  The R390s were
> designed to not have a panoramic bandwidth.
>
> Regards, Larry
>
> On Thu, Apr 18, 2019 at 3:56 PM jm <josemic at gmail.com> wrote:
>
>> Hi fellows!
>>
>> Taking advantage of the IF external connection of the receiver, I have
>> been
>> using it with my SDR dongle. It is a Funcube pro+ and the  sdr software is
>> Gqrx running under linux. I have to thank my son the program settings and
>> his willingness to help me with the obscure world of linux.   The
>> combination of both new and old technology runs smoothly.
>>
>> Obviously, the program is tuned to 455 kcs and the bandwith used in the
>> 390
>> is its maximum capability,  16 kcs.
>>
>> I am impressed by the technical level of the people in the list and hope
>> not to be an annoying beginner that makes silly questions.
>>
>> In spite of the above, here are my questions:
>>
>> 1. I was surprised about the floor level in the sdr sofware. The floor is
>> -100 db which is very low, in my opinion, according to what I have read
>> about the 390. I don't aspire to have a receiver whith a 'galactic level'
>> as Mr. Rippel says, but this is far from expected. Does that level
>> correspond to the r390 or is it the sdr receiver level (funcube)?
>>
>> 2. I read somewhere that it is possible to feed the sdr receiver through
>> some point of the 390 with the result of obtaining a much widest
>> bandwidht.
>> I remember that could be extended to 1 mhz. The current 16khz is
>> appropriate for amateurs chunks of bands but in broadcasting the reception
>> is limited to only one station.
>>
>> Many thanks as always and happy Easter!
>>
>> Jose
>> EA8DCP
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>