I use a miniRadio Solutions VNA ‘Tiny’… it covers 1MHz-3GHz for cheap!

Just updated to v16 – Thanks for adding the HIDE!!
And the trigger is pretty cool – now I can see the burst tx channel power as well.

Hi AJ,

When would you be able to look at adding a hide button/checkbox for the traces?
I dont want to delete the data, which OFF does, simply hide it from view to bring other waveforms to the front…

i.e. max hold on trace one, grab my rf burst, disable updating of max. max hold on trace three, grab different rf burst, disable updating of max, then use the ‘hide’ button to swap between them…

Cheers,
Jared

An update on EMC debugging (with BB60C).
We had a particularly troublesome HDMI port and due to the frequencies involved in measuring it, a lack of a suitable BW oscilloscope for signal ringing, eye-pattern and jitter analysis. Not to mention suitable differential probes…

I was looking at making some coupling transformers with a couple of secondaries such that I could connect them in-phase and out-of-phase to get differential/common mode signal levels. Again the bandwidth of the signal proved problematic for suitable magnetics.

However I recalled an article I found some time ago, which uses a hybrid coupler to transform a differential pair input into two single ended outputs – one differential mode, the other common mode. So after hacking some short SMA pig-tails onto an HDMI connector (also made a USB and Ethernet one) I then just connected up to the BB60C and had the HDMI display a fixed image. This gave me a defined spectral content signal. Then I just displayed that test signal on the two iterations of PCB layout and observed the drastic reduction a carefully considered layout makes…

Hi,
I have a little MiniVNA-tiny from miniradio solutions.
Works very well though there is room for improvement and the UI is clunky compared to Spike…
J

Hi Justin/AJ,
Thanks for your replies!
The packet based method might work for us…

Thanks for the explanation around USB3. I didnt get a BB60C for home because none of my home machines have USB3! It made the justification to the other half untenable trying to get both a BB60C AND a new machine!

@work I have a USB3 laptop so no issues here.

The SA44B has sufficient real time bandwidth (250kHz) and certainly covers the audio frequency range (1Hz to 4.4GHz).
The low end detection of -151dBm is more than capable of picking up low level signals.

The only issues I see are:
– you must block any and all DC
– its an RF device so its input impedance is 50ohms. Not 1Meg//28pF like the HP unit.
– you should probably put an in-line attenuator to make sure the input doesnt exceed +10dBm (into 50R)

So the answer is yes, in theory. In practice it may be more involved…

Hope this helps,
Regards,
Jared

Also, is there a plan at any point to limit the bandwidth so the BB60C will run on USB2.0?

Hi AJ,

I’ll have a look to see what it does in the other modulation modes.
I guess the ability or inability to do clean burst and transitions depend on how youve done the hardware implementation (i.e. antenna switch, PA input switch/enable…)

I’m after a burst (n-packets) so we can simulate the ISM performance which is duty-cycle limited to 0.1% in our application.
A clean first RF isnt critical for us, but probably something you should address long term.

We had all manner of problems with our ISM links in the office a day or so ago… (I’d lifted the in-band noise floor CONSIDERABLY by forgetting to turn off the RF O/P)

Hi AJ,

The connection difficulties occurred quite often when running through a USB3 hub (thinkpad dock-like thingy) even with both connectors plugged in. This went away when I moved it to the laptop-side USB3 ports.

With the BB60C taking up two ports I’m running out!

Regards,
Jared

A burst transmission mode button – transmits ‘n’ packets?

Haha nice!
I just got the ones on the left hand side.
I’ve made some NF probes with RG405 rigid, but havent had a chance to characterise them yet.

Minicircuits make a bunch of good kit that isnt too expensive and probably suitable for the wideband amp.

I have a loan BB60C and VSG25A (thanks to Bruce and Ken!!) to play with and now I have to say I want one of each of these now too!

TEM cell is 99% finished (just needs some platen braces) and is looking pretty swish!

Jared

Also,
Can you make them hardware non-specific? with some bounds checking pulled from the connected hardware.
There is no reason why my SA44B presets shouldnt work on the BB60C for example (they are just EMC freq range, amplitudes and RBWs).

Thanks!
I’ll have a play with the VSG now…

Hi Andrew,
You could also load a Presets path in the settings section…

Cheers,
Jared

FYI –
http://www.wa5vjb.com/products1.html (PCB antennas)
http://www.ewh.ieee.org/soc/emcs/acstrial/newsletters/summer08/pp2.pdf (Tem cell)
http://beehive-electronics.com/probes.html (Near Field probes – I really should get around to ordering some of these…)

Hi Julian,

As possibly the person who is the culprit of the list of features AJ now has on his to-do list, here’s how I used my SA44B (oh for a BB60C!).

You can get around QP by using both Peak and Average. QP is proportional to signal duty/waveforms/etc so will always be bracketed by either Pk or Avg.
More important is the RBW, as this needs to be the same or close to that defined in the appropriate standard. I just left everything set to 9kHz.

I found the most useful feature for EMC debugging is the demodulation to audio for signal identification. Especially when in real-time mode.

For EMC debug you dont necessarily need calibrated antennas as you are looking for relative changes. However most RF compliance labs will charge to calibrate and to provide antenna factors vs frequencies.
Precompliance is slightly different as its typically the first test so you wont have a benchmark. Again, a local lab may be able to rent to you a calibrated antenna (with factor table) or calibrate your antenna against a known standard.

By way of an example, I have made a whole bunch of near-field probes, made a couple of PCB-based log periodic antennas and have almost finished an open TEM cell.

You might want to have a read of my other posts (on the Spike sub-forum) about feature requests. They all stemmed from an EMC debugging exercise.

Which, I have just been informed, now passes.

Rgds,
Jared

Totally keen!
Anything I can do to help debug etc…

jared

Hi Bruce,
I’d certainly be keen as we use this in our ISM radio section.
I’d be happy to act as a guinea pig for any beta testing too if you need it.

Regards,
Jared

Could you not move the naming field from an external file into the relevant preset.ini?

Doh!

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