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Hi Eric and everyone, Happy Holidays
Updated my two Ultras ((from Zeenko), to ver 191. No issues and everything works as expected. However, I happened to notice an unusual spur on one unit that did not occur on the other one, This with no input, and both inputs terminated, and the units placed next to each other. They both showed the internal spurs that normally have occurred that will come and go intermittently (Spur removal is ON in both units) . In the plot pix below, both units are in MAX HOLD and left tracking for several minutes.? FIG 1 is the unit with the substantial intermittent spur of substantially higher amplitude at 3.995GHz that only occurs on this unit, the other marked spur positions are normal (seen all the time at the same spectral positions on both units)? that come and go, as does this bad one. FIG 2 is the other unit showing the normal? spectrum with the inputs terminated.
FIG 1? FIG 2? Not a big issue to me as I don't often work in the affected band, but I'm just curious as to what might be the source of this. It's internal to the unit and not picked up in the environment as it doesn't appear on a non-ULTRA analyzer.
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Hi Ted,
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I just tested my TinySA Ultra using same setup parameters that you used and mine shows no spurs. ?I have the RF port terminated with my 50 ohm calibration load.
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My unit is running old software 1.4083. ?My unit is running on batteries, no USB cable connected to it.
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Just FYI,
Don
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The LO of one tinySA will cause spurs on the other tinySA.
Can you test if they are far apart
--
Designer of the tinySA
For more info go to
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THX for the quick reply Eric and Don. I have done a bit more testing with the units on batt and separated (actually one under test is on and the other off). As in my earlier post one unit has no issues as you describe yours Don, and with the antenna does show a couple bands of traffic within the spectrum under test but at low levels. The other questionable unit shows excessive what looks like ingress that appears to be traffic of some kind in the commercial wifi licensed band in 3ghz. This with a terminated input. Testing with a test reference carrier at 4056GHz, transmitted at -10dbm from 6feet away, both units show it normally in the spectrum under test with the antenna input, and the test carrier is not visible with terminated inputs on either unit. But the traffic still is visible on the one questionable unit.?
Very interesting issue!. Also, in a wide band view, the spikes I called spurs are actually ambient wifi from the close proximity routers, they are always picked up and not any problem.
I have a few more tests to make and plots to take which I’ll report back with Thursday.
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On Dec 24, 2024, at 10:55 AM, Erik Kaashoek <erik@...> wrote:
? The LO of one tinySA will cause spurs on the other tinySA.
Can you test if they are far apart
--
Designer of the tinySA
For more info go to
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Hello Ted,
This may seem like a long shot, but I would open up the offending
TinySA and check the shields are properly located in their clips.
Either way, I would remove any shields, clean their edges with
isopropyl alcohol, metho, deoxit, etc then reseat the shields making
sure the clips on the pcb engage properly with the edges of the
shields. It might pay to take the case off your good unit to use as
a visual reference.
I noticed signals in the WiFi band in your photos. I suspect the
shield is not properly fitted and the shield and pcb are acting as a
slot antenna. Hence the frequency selectiveness.
Like said, a long shot, but worth a try.
HTH...Bob VK2ZRE
On 25/12/2024 3:39 pm, Ted Chesley
wrote:
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THX for the quick reply Eric and Don. I have done a bit more
testing with the units on batt and separated (actually one under
test is on and the other off). As in my earlier post one unit has
no issues as you describe yours Don, and with the antenna does
show a couple bands of traffic within the spectrum under test but
at low levels. The other questionable unit shows excessive what
looks like ingress that appears to be traffic of some kind in the
commercial wifi licensed band in 3ghz. This with a terminated
input. Testing with a test reference carrier at 4056GHz,
transmitted at -10dbm from 6feet away, both units show it normally
in the spectrum under test with the antenna input, and the test
carrier is not visible with terminated inputs on either unit. But
the traffic still is visible on the one questionable unit.?
Very interesting issue!. Also, in a wide band view, the
spikes I called spurs are actually ambient wifi from the close
proximity routers, they are always picked up and not any
problem.
I have a few more tests to make and plots to take which
I’ll report back with Thursday.
On Dec 24, 2024, at 10:55 AM, Erik
Kaashoek <erik@...> wrote:
?
The LO of one tinySA will cause spurs on the other
tinySA.
Can you test if they are far apart
--
Designer of the tinySA
For more info go to
|
Hi Ted (and Erik),
?
I repeated my test and I do notice if I’m close to my wireless router (like 10 feet from it) my TinySA Ultra does pick up my wireless router signals even with my 50 ohm termination on the RF port. ?What’s interesting is that my Ultra does not pick up my wireless router signals if I wrap the Ultra in aluminum foil with the aluminum foil in contact with the outside of the RF jack with or without my 50 ohm termination connected and I’m not covering the end (center pin area) of the RF jack with the aluminum foil. ?This test indicates that RF is not entering via the RF antenna jack (terminated or unterminated) but rather via the plastic case or screen.
My Ultra was purchased from R&L and totally happy with its performance but this is an interesting issue/topic.
Just FYI,
Don
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glue the case with copper foil and don't forget about the display. I have cells with aluminum foil, I didn't have copper at hand, but the result is not very good, in half a meter everything leaks evenly.
Hi Ted (and Erik),
?
I repeated my test and I do notice if I’m close to my wireless router (like 10 feet from it) my TinySA Ultra does pick up my wireless router signals even with my 50 ohm termination on the RF port.? What’s interesting is that my Ultra does not pick up my wireless router signals if I wrap the Ultra in aluminum foil with the aluminum foil in contact with the outside of the RF jack with or without my 50 ohm termination connected and I’m not covering the end (center pin area) of the RF jack with the aluminum foil.? This test indicates that RF is not entering via the RF antenna jack (terminated or unterminated) but rather via the plastic case or screen.
My Ultra was purchased from R&L and totally happy with its performance but this is an interesting issue/topic.
Just FYI,
Don
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Don
The tinySA shielding is a balance between cost and performance?
Above 1 GHz it is very difficult to have? "perfect" shielding
Feel free to open the case and have a look at the current shielding and feel free to improve the shielding
--
Designer of the tinySA
For more info go to
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Hi, this is my good old idea. I've been trying to? test for over a year. What do you think about applying a layer of copper inside the case, copper coatining. How much better is that? Has it been tried before? If it is better, how much more expensive would the product be for this improvement? I heave this spray: 843AR-340G Conductive Coating, Silver Coated Copper, EMI/RFI/EMF/EMC Shielding, Brown, Aerosol, On Wed, Dec 25, 2024, 5:46?PM Святослав Маханьков via <svyatoslavx= [email protected]> wrote:
glue the case with copper foil and don't forget about the display. I have cells with aluminum foil, I didn't have copper at hand, but the result is not very good, in half a meter everything leaks evenly.
Hi Ted (and Erik),
?
I repeated my test and I do notice if I’m close to my wireless router (like 10 feet from it) my TinySA Ultra does pick up my wireless router signals even with my 50 ohm termination on the RF port.? What’s interesting is that my Ultra does not pick up my wireless router signals if I wrap the Ultra in aluminum foil with the aluminum foil in contact with the outside of the RF jack with or without my 50 ohm termination connected and I’m not covering the end (center pin area) of the RF jack with the aluminum foil.? This test indicates that RF is not entering via the RF antenna jack (terminated or unterminated) but rather via the plastic case or screen.
My Ultra was purchased from R&L and totally happy with its performance but this is an interesting issue/topic.
Just FYI,
Don
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I found the dissipating shielding material to work better than reflective shielding when using this type of application. I use the nickle version (lossy)and it works surprisingly well. Expensive but works.You don't want to use highly reflective spray like the copper spray since you don't want to create cavity effects inside the case. That said, you still have to work with the big opening of the display. There are some commercial display screens that I am aware of, but you lose the touch screen function.
?
John
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Hi You suggest use this type of material inside of case instead copper spray??
I found the dissipating shielding material to work better than reflective shielding when using this type of application. I use the nickle version (lossy)and it works surprisingly well. Expensive but works.You don't want to use highly reflective spray like the copper spray since you don't want to create cavity effects inside the case. That said, you still have to work with the big opening of the display. There are some commercial display screens that I am aware of, but you lose the touch screen function.
?
John
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One of the issues with sprays/coatings is the question of adhesion over time.?? That conductive coating is all well and good as long as it stays attached to the inside of the case, but when flakes start falling off, it's a problem.?
John K5MO
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Prior surface preparation is a must, I use spray coating for the last 10 years on different projects. I have not yet had a problem with flaking of a proper prepared surface. Prepare your surface according to the vendor and? and it will work fine.
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is it necessary to use direct sprying or some primer for plastic before coating? Is? emi fiber type?? Is emi rfi fiber tape good enough for this purpose?
Prior surface preparation is a must, I use spray coating for the last 10 years on different projects. I have not yet had a problem with flaking of a proper prepared surface. Prepare your surface according to the vendor and? and it will work fine.
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John Cunliffe W7ZQ