A group somewhere would be nice to keep all the information and links
consolidated in one location.
Yahoo can be a pain at times, but does a fair job of having the ability
to store pictures, files, and links.
Let me start the links off with the SPECAN update I just posted on my blog
kv4qb.blogspot.com
DuWayne KV4QB
On 8/29/2015 10:10 AM, Ross Bell wrote:
Hi Amogh:
great idea toa start group for all vu2ese projects
On Sat, Aug 29, 2015 at 5:52 AM, Amogh Desai <desai.amogh@xxxxxxxxx <mailto:desai.amogh@xxxxxxxxx>> wrote:
I suggest making a hfsignals group to discuss all vu2ese projects.
What say?
Amogh
VU3DES
On 29 Aug 2015 5:46 pm, "Paul Chebi" <paul.chebi@xxxxxxx
<mailto:paul.chebi@xxxxxxx>> wrote:
I too am building the SWEEPERINO and wonder if there is a
Yahhoo group for it. Building was easy Manhattan style but I
anticipate some
questions when I get to the software and running it.
On Aug 29, 2015 5:34 AM, gurudatta panda
<gurudattabam@xxxxxxxxx <mailto:gurudattabam@xxxxxxxxx>> wrote:
>
> Dear Farhan,
> I think the RF Detector part is same as PHSNA as done by
W7ZOI, and that PCB can be used here with a little or no
modification only.
> Guru
>
> On Fri, Aug 28, 2015 at 7:46 PM, Ross Bell
<bellrossjr@xxxxxxxxx <mailto:bellrossjr@xxxxxxxxx>> wrote:
>>
>> Hi Ashar:
>> The Specan is something I can build with my limited
resources, I am a newbie when comes to using the arduino IDE,
case in point I am still having problems trying to compile the
sweeperino sketch , was wondering where the si5351 comes into
play even though you are using the Si570. I want get the
sweeperino built but until I get past this hurdle the project
is stalled. Any help is greatly appreciated, as a side note I
built a BITX20 still use it once in a while fun project.
>>
>> 73 Ross Bell K7RSB
>>
>> On Fri, Aug 28, 2015 at 6:45 AM, Joe Rocci <joe@xxxxxxxxxx
<mailto:joe@xxxxxxxxxx>> wrote:
>>>
>>> Yes, the sampling rate would have to be slow to
accommodate detecting the low frequencies involved in a narrow
resolution bandwidth. We actually had a 300 khz BW
post-detection LPF and the requirement wasn’t for fast
real-time refresh. It was a remote monitor unit on a broadband
network that characterized a 5-200 mhz spectrum, plotting the
spectrum on a remote display in a Network Operations Center
(NOC). It worked well for its purpose. I I think it might be
all that many hams might need, given the minimal complexity.
Clearly, it’s not going to replace a high quality (read “High
Priced”) lab instrument, but it’s much more than just a
“curiosity”. Also, your idea of a DSP back-end could help, but
I think you’d have to deal with the issue of images in the DC
detection process resulting in 2 responses, whereas the
envelope measurement approach merely folds the image in as
half of the resolution BW. However, if the “mixer” were a
Tayloe-style QSD, you might fix that problem too.
>>>
>>> Joe
>>>
>>> From: Ashhar Farhan
>>> Sent: Friday, August 28, 2015 9:34 AM
>>> To: minima@xxxxxxxxxxxxx <mailto:minima@xxxxxxxxxxxxx>
>>> Subject: [minima] Re: A homebrew spectrum analyzer
>>>
>>> joe,
>>> at audio frequencies, we could just rely on a sound card
to read 16-bit audio and convert it to 70 or 80 db scale. i
have tried this approach. upconvert to 100 Mhz and run a
product detector at 100 MHz. the trouble is the sampling rate
is quite slow.
>>> let me illustrate the problem : to scan 0-60 MHz, given 20
Khz sampling bandwidth, we will need 60,000/20 = 3000 data
points. each datapoint would take about 10 msec. the entire
sweep would take 30 seconds.
>>> however, the great achievement could be if we ran dsp
inside the audio bandwidth too and thus, provided a variable
resolution bandwidth in software.
>>> - f
>>>
>>> On Fri, Aug 28, 2015 at 6:55 PM, Joe Rocci <joe@xxxxxxxxxx
<mailto:joe@xxxxxxxxxx>> wrote:
>>>>
>>>> A real minimalist might build a spectrum analyzer out of
a direct conversion receiver architecture. The resolution
bandwidth turns out to be twice the output audio bandwidth,
making it easy to obtain variable resolution bandwidth. The
major obstacle is that the DBM has an inherent response at the
3rd harmonic of the LO only about 15 db down. I actually
designed a product based on this approach many years ago. I
cured the 3rd harmonic problem with a bank of 4 switched
lowpass filters in the front-end.
>>>> Worked very nicely. We sampled the “audio” response with
an 8-bit A-D, which limited our dynamic range to about 40 dB.
Using an AD8307 at the output would vastly improve this.
>>>>
>>>> Joe
>>>> W3JDR
>>>>
>>>>
>>>> From: Ashhar Farhan
>>>> Sent: Friday, August 28, 2015 8:34 AM
>>>> To: minima@xxxxxxxxxxxxx <mailto:minima@xxxxxxxxxxxxx>
>>>> Subject: [minima] Re: A homebrew spectrum analyzer
>>>>
>>>> thanks all. you will understand that this is a reprise of
the original by wes and terry. the two papers written by them
are linked in my article. do give it a read.
>>>>
>>>> - f
>>>>
>>>> On Fri, Aug 28, 2015 at 5:23 PM, Biagio Pepe
<blaispe@xxxxxxxxx <mailto:blaispe@xxxxxxxxx>> wrote:
>>>>>
>>>>> Fantastic Job Fahran !!! Really a brilliant work
>>>>> Simply Love it
>>>>> 73's
>>>>>
>>>>> 2015-08-28 7:01 GMT+02:00 Ashhar Farhan
<farhanbox@xxxxxxxxx <mailto:farhanbox@xxxxxxxxx>>:
>>>>>>
>>>>>> While working on the Minima project, I needed a
spectrum analyzer to measure the performance. The new specan
is as complicated as a simple SSB rig, probably even simpler.
>>>>>>
>>>>>> This is an Si570/Arduino controlled spectrum analyzer
that can be built for less than hundred dollars. It is simple
to build and it can be used to measure IMDR, spurs, harmonics,
etc. It doesn't need an oscilloscope.
>>>>>>
>>>>>> I like you all to read about it
http://hfsignals.blogspot.in/p/specan-reboot-of-w7zoi.html
>>>>>>
>>>>>> - f
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>
>
> --
> Thanks & Regards
>
> Gurudatta Panda
> Jr. Site Engineer
> R.V.N.L. / KDJR
>
> Mob : +91 9777447844 <tel:%2B91%209777447844> (Work)
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