[R-390] r390a and SDR

[jm]

Thanks Larry. 50-60 khz would be a good improvement.

Regards, Jose

El vie., 19 abr. 2019 a las 9:00, jm (<josemic at gmail.com>) escribió:

> 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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>>