General questions and wish list for WSUB1G model
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Ken Wyatt
Feb 12, 2012, 10:58:03 PM2/12/12
to RF Explorer
Hi, I have some questions and a few "wish list" items. I recently
purchased the WSUB1G model for EMC troubleshooting.
1. I'm curious why the "RF Generator" function is not implemented?
Does this not have that functionality in the 443X transceiver?
2. I wonder how hard it would be to allow switching between dBm and
dBuV? This would be a simply math function and would convert the unit
more in line with many EMI receivers or spectrum analyzers. All you'd
need to do would be to take dBm and add 107. This toggle might very
well be placed into Attenuator Menu; "something like, "Y-Axis: dBm/
dBuV".
3. I love the fact you have added various Peak, Average, Max Hold, etc
modes, but perhaps a more common term for these might be "Mode" or
"Sweep Mode" - more an industry standard - rather than "Calculator".
Just a suggestion. :-)
4. "Top and Bottom dBm" in the Attenuator Menu is OK, but again, the
more familiar term for these might be "Reference Level" in place of
"Top dBm" and "Vertical Scale (dB)". This would allow the user to set
the (top) reference level in dBm and then the scale setting
(typically, 1, 2, 5, 10, 20 dB), which would define the "Bottom dBm".
Just another, but more conventional way of setting the scale. I can
live with it as is, though.
5. It would be nice to at least have the resolution BW displayed,
either at the bottom of the left-hand panel, or maybe the upper-right
of the main screen. Even better, would be to allow user setting of
this. Again, I can live without...
6. Is there a Video BW setting? I'm guessing not... :-)
7. Is the antenna port AC-coupled? From the schematic, it appears not.
Placing a small capacitor in series would provide a DC block and help
protect the input preamp.
8. Is it possible to add back-to-back diodes, or some other RF (and
ESD)-protective devices from the input port to chassis ground? This
would serve as additional protection of the front end.
9. Is there to be an updated manual soon that includes the WSUB1G
model?
10. By the way, mine also seems to be reading about 5 dB low (same as
a previous poster). I plan to characterize this in more detail.
Well, there's my initial "brain-dump" after using the unit for a
couple days and going over the v1.05 manual.
Thanks for the amazingly small and inexpensive spectrum analyzer
design! After retiring recently as an EMC engineer for HP and Agilent
Technologies, I'm amazed at the feat you've accomplished.
Cheers, Ken
purchased the WSUB1G model for EMC troubleshooting.
1. I'm curious why the "RF Generator" function is not implemented?
Does this not have that functionality in the 443X transceiver?
2. I wonder how hard it would be to allow switching between dBm and
dBuV? This would be a simply math function and would convert the unit
more in line with many EMI receivers or spectrum analyzers. All you'd
need to do would be to take dBm and add 107. This toggle might very
well be placed into Attenuator Menu; "something like, "Y-Axis: dBm/
dBuV".
3. I love the fact you have added various Peak, Average, Max Hold, etc
modes, but perhaps a more common term for these might be "Mode" or
"Sweep Mode" - more an industry standard - rather than "Calculator".
Just a suggestion. :-)
4. "Top and Bottom dBm" in the Attenuator Menu is OK, but again, the
more familiar term for these might be "Reference Level" in place of
"Top dBm" and "Vertical Scale (dB)". This would allow the user to set
the (top) reference level in dBm and then the scale setting
(typically, 1, 2, 5, 10, 20 dB), which would define the "Bottom dBm".
Just another, but more conventional way of setting the scale. I can
live with it as is, though.
5. It would be nice to at least have the resolution BW displayed,
either at the bottom of the left-hand panel, or maybe the upper-right
of the main screen. Even better, would be to allow user setting of
this. Again, I can live without...
6. Is there a Video BW setting? I'm guessing not... :-)
7. Is the antenna port AC-coupled? From the schematic, it appears not.
Placing a small capacitor in series would provide a DC block and help
protect the input preamp.
8. Is it possible to add back-to-back diodes, or some other RF (and
ESD)-protective devices from the input port to chassis ground? This
would serve as additional protection of the front end.
9. Is there to be an updated manual soon that includes the WSUB1G
model?
10. By the way, mine also seems to be reading about 5 dB low (same as
a previous poster). I plan to characterize this in more detail.
Well, there's my initial "brain-dump" after using the unit for a
couple days and going over the v1.05 manual.
Thanks for the amazingly small and inexpensive spectrum analyzer
design! After retiring recently as an EMC engineer for HP and Agilent
Technologies, I'm amazed at the feat you've accomplished.
Cheers, Ken
Ariel Rocholl
Feb 14, 2012, 8:17:17 PM2/14/12
to rf-ex...@googlegroups.com
Hi Ken,
Thanks for your support on the RF Explorer and certainly for taking the time to populate such a great list of comments and suggestions from an HP/Agilent expert.
Some of them may justify a whole thread on itself, but I will try to summarize some quick answers, let me know if you need more details.
Q: I'm curious why the "RF Generator" function is not implemented?
Does this not have that functionality in the 443X transceiver?
A: The WSUB1G doesn't use a transceiver but a wideband receiver. A wideband RF Generator is on the plans as an Expansion Module, we expect to have it available at some point in 2012. It will offer tracking generator functionality as well as sweep and standard RF generator functionality.
Q: I wonder how hard it would be to allow switching between dBm and
dBuV? This would be a simply math function and would convert the unit
more in line with many EMI receivers or spectrum analyzers. All you'd
need to do would be to take dBm and add 107. This toggle might very
well be placed into Attenuator Menu; "something like, "Y-Axis: dBm/
dBuV".
A: That is a great suggestion and an easy addon, no user had asked for it yet but I expected that coming at some point. Assuming 50ohm support only, the math is really easy. I will put that on the todo list for upcoming firmware upgrade.
Q: I love the fact you have added various Peak, Average, Max Hold, etc
modes, but perhaps a more common term for these might be "Mode" or
"Sweep Mode" - more an industry standard - rather than "Calculator".
Just a suggestion. :-)
A: Thanks for the suggestion :). Sweep Mode and Detector Mode are not really the same as Calculator Mode. Correct me if I am wrong but the first two are the way an SA will resolve the many reads that end up in a single dot on screen, at least on HP/Agilent analyzers (famous Application Note 150 comes to mind to describe Detector Mode). As RF Explorer currently supports 1:1 read/dot ratio only, there is no Sweep or Detector mode to apply. However, there is a Calculator which iterates through a number of previous read values, and do some calculations based on that. BK Precission SA uses the same definition for Calculator.In any case, Detector/Sweep Mode will be available as soon as RF Explorer firmware allows for larger span. I found newcomers to RF to easily understand what Calculator mode is and how it works, however Detector mode is a bit more advanced and require full understanding on how the sweep mechanism works.
Q: It would be nice to at least have the resolution BW displayed,
either at the bottom of the left-hand panel, or maybe the upper-right
of the main screen. Even better, would be to allow user setting of
this. Again, I can live without...
A: RBW is displayed on screen at the right bottom if you cycle between the two X axis display mode. Just click on [ENTER] while on the Spectrum Analyzer screen mode. Manually selecting the RBW may be useful for advanced users, but it is one of those parameters that can be easily misused by newcomers and lead to incorrect read. I will add your idea to the todo list for an "advanced mode" which may also include the "simulated" VBW and other parameters for a future upgrade.
Q: Is there a Video BW setting? I'm guessing not... :-)
A: No Sir :). Actually the VBW is something that was a real thing in old, fully analog SA. Modern digital analyzers implement a simulated VBW, that can be added to RF Explorer on the same "advanced mode" future upgrade.
Q: Is the antenna port AC-coupled? From the schematic, it appears not.
Placing a small capacitor in series would provide a DC block and help
protect the input preamp.
A: Very good question. It depends on the model. For the WSUB1G and upcoming WSUB3G, yes it is AC coupled. For other current models, it is not, but can be added externally with a SMA AC coupled adaptor.
Q: Is it possible to add back-to-back diodes, or some other RF (and
ESD)-protective devices from the input port to chassis ground? This
would serve as additional protection of the front end.
A: You can add an external SMA power limiter. The upcoming WSUB3G model will include ultrafast PIN protection diodes which will increase the absolute max input power up to about +30dBm (yet to be qualified).
Q: Is there to be an updated manual soon that includes the WSUB1G
model?
Q: By the way, mine also seems to be reading about 5 dB low (same as
model?
Q: By the way, mine also seems to be reading about 5 dB low (same as
a previous poster). I plan to characterize this in more detail.
A: These are in the short term todo list, but I wanted to finish the WSUB3G model first to do a more ambitious upgrade of both user manual and calibration features. Note the user manual has not the latest features described, but the Release Notes have them, so I suggest to check Release Notes if you have a chance.
Best regards,
Ariel Rocholl
Ariel Rocholl
Feb 15, 2012, 4:40:56 AM2/15/12
to rf-ex...@googlegroups.com
Q: It would be nice to at least have the resolution BW displayed,either at the bottom of the left-hand panel, or maybe the upper-right of the main screen. Even better, would be to allow user setting of this. Again, I can live without...
Actually the key to use for this is [RETURN] not [ENTER], sorry about that.A: RBW is displayed on screen at the right bottom if you cycle between the two X axis display mode. Just click on [RETURN] while on the Spectrum Analyzer screen mode. Manually selecting the RBW may be useful for advanced users, but it is one of those parameters that can be easily misused by newcomers and lead to incorrect read. I will add your idea to the todo list for an "advanced mode" which may also include the "simulated" VBW and other parameters for a future upgrade.
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