Re: WARNING: Measuring the spectral purity of a transmitter
On Fri, Aug 21, 2020 at 01:45 AM, Stephen Laurence wrote:
I cannot imagine anyone being so absent- minded as to connect any test gear (other than dummy load or a power meter/inline swr meter etc) to ANY transmitter or generator of rf.
You've apparently never used a signal generator from HP or Rohde & Schwarz and likely others.? Many of them have reverse power protection up to 50 watts, some up to 100 watts.? And you've apparently never used a communications service monitor, such as those from IFR, HP, Cushman, Motorola, and others.? Those are generally used for two-way radio service, and it is common to connect a transceiver to one.? Many of those will accept input power up to 100 watts, some as high as 150 watts.? If you had spent your career servicing mobile radios with a service monitor, you wouldn't think anything of keying up into a piece of test equipment. Of course, you'd learn a? quick lesson the first time (and hopefully last time) you keyed a 100 watt transmitter into your tinySA!
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Re: WARNING: Measuring the spectral purity of a transmitter
I usually use a 30dB high power attenuator for a watt to milliwatt conversion, with an additional 10 or 20 dB low power attenuator for power levels of 10 or 100 watts respectively.
Gary
W9TD
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Re: WARNING: Measuring the spectral purity of a transmitter
I mever nake mistteacks...
73,
Bill KU8H
bark less - wag more
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On 8/21/20 1:13 PM, John AE5X wrote: On Fri, Aug 21, 2020 at 03:45 AM, Stephen Laurence wrote:
I cannot imagine anyone being so absent- minded as to connect any
test gear (other than dummy load or a power meter/inline swr meter
etc) to ANY transmitter or generator of rf.
Then you have an unrealistic view of human nature. Humans, at times, make mistakes.
--
John AE5X
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Re: WARNING: Measuring the spectral purity of a transmitter
On Fri, Aug 21, 2020 at 10:20 AM, Brent DeWitt wrote:
If you have extra attenuators (big if), a simple test is to measure the harmonic with and without one
You better use the built in attenuator for testing the source of the harmonics
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Re: WARNING: Measuring the spectral purity of a transmitter
If you have extra attenuators (big if), a simple test is to measure the harmonic with and without one.? If the harmonic changes level by a value much different than the attenuator value, you're overloading the SA.
Brent, AB1LF
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Re: WARNING: Measuring the spectral purity of a transmitter
On Fri, Aug 21, 2020 at 03:45 AM, Stephen Laurence wrote:
I cannot imagine anyone being so absent- minded as to connect any test gear (other than dummy load or a power meter/inline swr meter etc) to ANY transmitter or generator of rf.
Then you have an unrealistic view of human nature. Humans, at times, make mistakes. ? -- John AE5X
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Re: WARNING: Measuring the spectral purity of a transmitter
I too use a tap to reduce the output of the device under test to acceptable levels for the test instrument.? I found a reference with all of the parts listed to make the tap, including the metal case for it.
One point I would make on the tap, be sure to run a characterization test (I used a NanoVNA for that test) to ensure a flat response over the frequency range in question.? I found that I needed to increase the capacitor specified to get a flat response (within 1 dB).? Ultimately I used a combination of capacitors that I had on hand to get the best match.
Just my 2 cents?
73
Evan
AC9TU
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Re: WARNING: Measuring the spectral purity of a transmitter
I have always used a simple 40 dB. tap to measure transmitter output.? Works with SA or a simple power meter to check output power, or a scope to check modulation.They are very easy and inexpensive to build.
DuWayne kv4qb
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Before we get a lot of replies of people all listing there wishlist I kindly request NOT to list these requests:
- A larger screen: This requirement is understood?and valid. IF there will be a next tinySA it probably will be a 4"
- Higher frequency range, preferably covering thill 3GHz. THis requirement is understood?but going till 3GHz with good performance AND low cost (sub 100$) will be EXTREMELY difficult. Yes, you can do an SDR type detector but getting good dynamic range combined with fast scanning and low cost is difficult. 3GHz will probably NOT be in the next tinySA (IF there will be a next tinySA). Some extension of the range may be possible.
- Lower smallest RBW. Yes, 2.4kHz is on the edge, 1kHz or even 100Hz would be nice. This requirement? is understood and IF there will be a next tinySA a step to smaller RBW MAY be possible
- LNA. A valid request. Making the internal 3.3V available to outside the enclosure and thus enabling the user adding a LNA (various amplifiers will work well on 3.3V) outside the enclosure and still be portable MAY be implemented IF there will be a next tinySA. There are in the current tinySA two connector holes at the edge of the PCB labeled with VDD. You can? use one of these to supply 3.3V for your pre-amp.
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Re: 'data 0' console command
"data 0" returns the "live or last? trace" when you do any of the CALC actions.
If no calculation is active "data 0" returns all zero's
"data 2" returns the output of the calculation
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Dear all,
?I have been playing with both my SAA2 2.8¡± and my SAA2 3.2¡± screen vnas while waiting for my SAA2 with N connectors and its 4¡±screen.
I have been playing with my Tinysa too. ?I found that the small increase to 3.2¡± screen size on the vna made a big difference for (ancient) me both using the touch screen and viewing the results. I suspect my small screen vna may be given to the next needy friend.
The small increase in Tinysa case size to accomodate the 3.2¡± screen would surely be worth doing without any other change to the main board etc and might allow a bigger battery and possibly a (user-fitted) internal preamplifier (externally patchable when required) to either high or low input for greater sensitivity when chasing sources of qrm.
My other wishlist entry is a UHF Tinysa with 300mhz to 3ghz coverage.
Steve L. G7PSZ
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Erik,
? ?One of my fellow ham club members asked me about the data 0?command while trying to use the output mask of the scan command. Looking through my notes, I remember you replying the following regarding data 0.
? "data?2 is the "live"?data, only different from?data?0?when doing a calculation (max hold, averaging, etc...)"
?data 0 now seems to have been depreciated and always returns an array of zero values regardless of live or stored trace values. What I currently see is the following:
? data 0:? always returns an empty array
? data 1:? returns stored trace
? data 2:? returns live trace
? Is this correct or have I missed something in my testing?? Are you reserving data 0 for a future feature like a second stored trace?
Herb
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Re: WARNING: Measuring the spectral purity of a transmitter
? ? ? I use a directional coupler when measuring the output of a transmitter.? The coupled port is -40dB down from the transmit level and the signal to the tinySA is well above its spur free range.?
? ? For protection when directly connected to other input sources, I purchased an RF Explorer power limiter which has a built-in power limiter, dc block and 6dB attenuator for input protection up to 30dBm.? Above 30dBm the power limiter becomes a sacrificial component rather than the tinySA.
? ? Both the directional coupler and power limiter were purchased to protect my higher priced spectrum analyzers.? They work just as well for the tinySA but each have the disadvantage of being priced at or above the cost of the tinySA.? The power limiter is spec'd to 3GHz which is over kill for the tinySA.? An interesting DIY project would be a power limiter or transient suppressor that only worked to the limits of the tinySA LOW or HIGH inputs.?
- Herb
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Re: WARNING: Measuring the spectral purity of a transmitter
I cannot imagine anyone being so absent- minded as to connect any test gear (other than dummy load or a power meter/inline swr meter etc) to ANY transmitter or generator of rf. Even leaving the extended telescopic attached to the Tinysa could damage it in the viscinity of a powerful PA especially if mismatched/poor grounding/leaky dummy load. ?You might be quite surprised how much RF you are exposing yourself to when transmitting - another use for the Tinysa.
I have used small 1,2 or 3 turn loops (insulated) about 1¡± diameter attached to a length of 316 coax very useful, also for sniffing around equipment and chaising sources of interference. The insulation is necessary in case components are touched by the loop. You can see what needs screening then (also useful as input to a scope sometimes).
Steve, G7PSZ
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WARNING: Measuring the spectral purity of a transmitter
A word of warning for those that want to measure the spectral purity of their transmitter.
As the tinySA is specced to accept +10dBm without attenuation and +30dBm for some seconds with maximum attenuation you may be tempted to connect the output of the transmitter to the tinySA, set the tinySA to max hold and transmit for a short time, long enough for one sweep.
Even when your transmitter stays below +30dBm you risk making a wrong measurement, or even worse, if you have attenuation on automatic, destroy the tinySA as the tinySA will only adjust (e.g. increase) the attenuation for the next sweep.
The spur free dynamic range of the tinySA is a bit above 70dB with an RBW of 300kHz. This means that any signal that is more than 70dB above the noise floor will cause internally generated harmonics.
Let's take an example:
Without attenuation and with an RBW of 300kHz the noise floor is at -95dBm. With an input signal of 0dBm you are 25dB above the spur free dynamic range so there will be internally generated harmonics.
For a good measurement you should apply 25dB of attenuation?
Make sure to update the FW of you first batch tinySA as the newer FW contains an overload warning (the marker info turns red) to help you make a good measurement.
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Re: tinySA has been listed in Alibaba store
On Thu, Jul 23, 2020 at 01:23 PM, Shirley Dulcey KE1L wrote:
If this first run is well received, I expect that the US companies that are reselling the NanoVNA-H (I know about R&L and Gigaparts) will make large purchases of the tinySA and resell it. They're a good alternative for US residents; delivered cost from R&L is about the same as ordering from Hugen's Alibaba store and you get it faster.
? Although currently out of stock, R&L Electronics in the US has announced that they will be selling the tinySA:? ??? ?My ham radio group has purchased many hugen products from R&L over the last year and have been very satisfied with their customer service and speed of delivery. ?- Herb
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On the other hand if vat or duty is due according to said countries rules. We, as in the customer, ought to pay it.
We should not avoid it. It pays towards our society services after all.
Otherwise we are as corrupt as other countries despotic leaders ..........just in a smaller way. Nevertheless still corrupt!
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On 18 Aug 2020, at 16:52, EB4APL <eb4apl@...> wrote:
?Today DHL delivered me a couple of tinySA.
Still no powered it up, but I want to note that the packaging was really good, thanks Maggie.
The only negative comment is about DHL. DHL is a carrier and also a customs clearance agent and they make extra money with it.
When using normal mail for receiving parcels from China usually I have not to pay anything, but DHL charged me 10€ for customs duties plus 20€ for the "service".
I forgot to say Maggie to sent it using common mail, it is cheaper for both.
I had a similar experience when I bought my first AirSpy SDR receiver, I choose FedEx or UPS (I don't remember which one) instead of common mail expecting a safer service, but when it arrived they called me asking for a ridiculous sum for clearing the customs. I refused and made the clearance myself, not before a long discussion about charging me just for giving me the shipping documents.
So when I bought another Airspy receiver I choose mail and the parcel arrived at my door without paying any extra.
This may not apply to all countries, but it is true for Spain and even worse for other countries.
Now I (and a friend) have another toy to play with.
Regards,
Ignacio EB4APL
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El software de antivirus Avast ha analizado este correo electr¨®nico en busca de virus.
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On Tue, Aug 18, 2020 at 08:13 AM, Dick wrote:
Can someone send me a link to the PC Control Software ?
Both links are on the wiki page
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Today DHL delivered me a couple of tinySA.
Still no powered it up, but I want to note that the packaging was really good, thanks Maggie.
The only negative comment is about DHL. DHL is a carrier and also a customs clearance agent and they make extra money with it.
When using normal mail for receiving parcels from China usually I have not to pay anything, but DHL charged me 10€ for customs duties plus 20€ for the "service".
I forgot to say Maggie to sent it using common mail, it is cheaper for both.
I had a similar experience when I bought my first AirSpy SDR receiver, I choose FedEx or UPS (I don't remember which one) instead of common mail expecting a safer service, but when it arrived they called me asking for a ridiculous sum for clearing the customs. I refused and made the clearance myself, not before a long discussion about charging me just for giving me the shipping documents.
So when I bought another Airspy receiver I choose mail and the parcel arrived at my door without paying any extra.
This may not apply to all countries, but it is true for Spain and even worse for other countries.
Now I (and a friend) have another toy to play with.
Regards,
Ignacio EB4APL
--
El software de antivirus Avast ha analizado este correo electr¨®nico en busca de virus.
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DSL dropped off my TinySA yesterday. A quick check with my
Sig Gen shows it works. Now to read the manual !!
One thing I need is the PC Software. I looked at the Wiki, saw
some pictures, but I didn't see a link to the software. Perhaps
I missed something.
?
Can someone send me a link to the PC Control Software ?
Thanks, Dick, W1KSZ
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Jim Allyn - N7JA
Gary W9TD
Brent DeWitt
DuWayne Schmidlkofer
Rachael M1AYG
Dick