[Skimmertalk] Difference of RP10 14 16

[Bob Wilson, N6TV]

Oh!  I had not noticed that.  So yes, that appears to be the way to assign
Port 2 for FT8 decoding on the RP itself.

73,
Bob, N6TV


On Fri, Jul 19, 2019 at 12:04 PM Björn Ekelund <bjorn at ekelund.nu> wrote:

> Bob,
>
> I believe my concept for cycling control scripts for Pavel's FT8 decoder
> actually allows you to use
> different antenna inputs for different bands. Without modifying start.sh.
>
> Each line in the files write-c2-files-*.cfg specifies which antenna input
> is used for the sample collection.
> I have not mentioned this in my write up since i have not tried it
> myself.
>
> ...
>   { freq  =  7.075500; chan = 1; },
> ...
>
> 73,
>
> Björn
>
> Den tors 18 juli 2019 kl 09:27 skrev Bob Wilson, N6TV <n6tv at arrl.net>:
>
>> Are you using a pre-amp?  Does it cover 6m?  My CliftonLabs does not.
>>
>> The SM7IUN scripts rotate the bands for day/twilight/night, but not the
>> antenna assignments.  It sounds like you have a workaround for that.  If
>> you make the last receiver of the eight in all three .cfg files always be
>> 6m, then it should work and always use antenna port 2 if using the start.sh
>> described in your post.
>>
>> 73,
>> Bob, N6TV
>>
>> On Thu, Jul 18, 2019, 12:10 AM Lee Sawkins <ve7cc at shaw.ca> wrote:
>>
>>> Bob
>>>
>>> Splitting the signal before the pre-amp is a bad idea.  It costs you at
>>> least 3.5 dB of s/n on all signals.
>>>
>>> I am using an RP-14 for 8 bands of FT8 skimming.
>>>
>>> As per your instructions I set 6 meters to Antenna "2" and the other 7
>>> bands to "1" in "sdr_receiver_hpsdr/start.sh" "1 1 1 1 1 1 1 2 &"
>>>
>>> All bands except 6 meters have spotted FT8 stations.  There has been
>>> activity on 6.
>>>
>>> After not receiving any 6 meter spots I took another very careful look
>>> at the setup info at https://sm7iun.ekelund.nu/red-pitaya/ft8-skimmer
>>>
>>> "You may also want to modify the band selection for the three daylight
>>> periods. This is done by commenting/uncommenting the corresponding lines.
>>> If you do this, make sure you activate exactly eight bands and also keep an
>>> eye on the commas for correct syntax. The number after "chan ="  is the
>>> input used for that frequency. The receiver thus supports the use of two
>>> different antennas."
>>>
>>> My understanding from this is that you can select which antennas you
>>> want, either "1" or "2" for each band for each time period.  I am using an
>>> RP-14 with 8 bands selected.  I have now selected "chan = "2" for only 6
>>> meters for all 3 time periods.  The other bands all use antenna = "1".
>>> Unfortunately 6 is dead right now.  Tomorrow I will hopefully see whether
>>> this works for 6.
>>>
>>> There is no mention of using "sdr_receiver_hpsdr/start.sh" for antenna
>>> selection in the write up.
>>>
>>> Lee
>>>
>>> ----- Original Message -----
>>> From: Bob Wilson, N6TV <n6tv at arrl.net>
>>> To: SkimmerTalk Reflector <skimmertalk at contesting.com>
>>> Sent: Wed, 17 Jul 2019 11:08:42 -0600 (MDT)
>>> Subject: Re: [Skimmertalk] Difference of RP10 14 16
>>>
>>> On Tue, Jul 16, 2019 at 4:07 PM Lee Sawkins <ve7cc at shaw.ca> wrote:
>>>
>>> > It's a trade off for me. Sensitivity on high bands with a 20 dB
>>> pre-amp or
>>> > a few busted calls on lower bands.
>>> >
>>>
>>> Well, since the RP has two antenna inputs, one can assign the low band
>>> slices to antenna input 1 (no preamp), and the high band slices to input
>>> 2
>>> (with preamp).  If using one common antenna, use a splitter:
>>>
>>>                                                    +------------> Input1
>>> (Low Bands)
>>> Antenna -> Front End Protector -> Passive Splitter +
>>>                                                    +-> Pre-amp -> Input2
>>> (High Bands)
>>>
>>> A passive attenuator in the low band input could also achieve the same
>>> result.
>>>
>>> Antenna assignments for all 16 receiver slices are defined in
>>> *sdr_receiver_hpsdr/start.sh*, and are independent, but not dynamic, so
>>> this works best with no .ini file rotation in Aggregator.
>>>
>>> 73,
>>> Bob, N6TV
>>>
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