Be sure to set the filter bandwidth the same on both versions.
Gerald

Gerald Youngblood, K5SDR
President and CEO
FlexRadio Systems(TM)
13091 Pond Springs Road, #250
Austin, TX 78729
Phone: 512-535-4713 Ext. 202
Email: [email protected]
Web: www.flexradio.com <http://www.flex-radio.com/>

Tune In Excitement (TM)

PowerSDR(TM) is a trademark of FlexRadio Systems


On Fri, Nov 12, 2010 at 4:03 PM, Clay W7CE <[email protected]> wrote:

> Gerald,
> I tried what you suggested and reset the database for both 2.0.8 and
> 2.0.16.  PowerSDR 2.0.16 still shows the noise floor, as measured  by RX1
> Meter in "Sig Avg" mode, to be 3 dB higher than 2.0.8.  Using SpecJT, both
> versions show the same average noise power when AF and AGC-T are set to 50
> and 60, respectively.  It appears that something has changed in the way the
> S-Meter reading is calculated.  Rough calculations based on RX noise figure
> and current sky temperature, lead me to believe that the 2.0.8 reading is
> more accurate.
>
> I'm getting ready to hook up my 5000A, which I just got back with the V/U
> upgrade, and will see if it behaves similarly.  I'll also try the 1500
> later.
>
> 73,
> Clay  W7CE
>
>
> On 11/12/2010 6:11 AM, Gerald Youngblood wrote:
>
>> Clay,
>>
>> Try starting with a clean database on both versions.  This is probably
>> calibration data in the database and not an actual change in the noise
>> floor.
>>
>> Gerald
>>
>>
>> Gerald Youngblood, K5SDR
>> President and CEO
>> FlexRadio Systems(TM)
>> 13091 Pond Springs Road, #250
>> Austin, TX 78729
>> Phone: 512-535-4713 Ext. 202
>> Email: [email protected] <mailto:[email protected]>
>> Web: www.flexradio.com <http://www.flex-radio.com/>
>>
>>
>> Tune In Excitement (TM)
>>
>> PowerSDR(TM) is a trademark of FlexRadio Systems
>>
>>
>> On Fri, Nov 12, 2010 at 1:39 AM, Clay W7CE <[email protected] <mailto:
>> [email protected]>> wrote:
>>
>>    I just installed 2.0.16 on a Win7 Ultimate 64-bit machine
>>    (upgrading from 2.0.8).  Initially, I'm running it with a Flex
>>    3000, and it upgraded the firmware in the 3000 to 2.0.4.1.  The
>>    FlexRadio Firewire driver stayed the same at 3.5.2.8028.  After
>>    initial manual setup, I checked the local noise floor on 6M with
>>    the antenna pointed in what is typically my quietest direction and
>>    with the antenna elevated 40 degrees (to minimize the effects of
>>    any man-made QRN).  The noise floor seemed high, so I shutdown
>>    2.0.16 and started 2.0.8.  It seems to work with the firmware
>>    upgrade, so I went to the same frequency and the indicated noise
>>    floor is 3 dB lower (better).  Several iterations of switching
>>    versions yielded the same results.  As far as I can tell, the two
>>    versions are configured identically.  Both versions of the
>>    software are set to USB, 2.7k BW with the NB and SR off.  Also the
>>    RX1 Meter is set to "Sig Avg" in both cases, and they both have
>>    AGC-T set to 69 and Pre2 selected.  I've also noticed that the
>>    noise displayed in the panadapter seems to have a larger range of
>>    min and max peaks on 2.0.16 compared with 2.0.8.
>>
>>    Why do the two versions show a different noise floor when used
>>    with the same receiver and antenna?  Also, if there is a reason
>>    for the difference, which is more accurate?
>>
>>    Tomorrow I should get a chance to try 2.0.16 with a Flex 5000A and
>>    a 1500.  It will be interesting to see if there are differences in
>>    the indicated noise floor on those two receivers when I switch
>>    PowerSDR versions.
>>
>>    73,
>>    Clay  W7CE
>>
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>>
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>>    This is the FlexRadio Systems e-mail Reflector called FlexEdge.
>>     It is used for posting topics related to SDR software development
>>    and experimentalist who are using beta versions of the software.
>>
>>
>>
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