It’d be kind of cool to see a vertical bar representing channel power on the spectrum plot, and then you could show the video trigger threshold on that. Just throwin’ out ideas…

Good deal. I’m glad they worked!

We spoke on the phone this morning. To summarize for people troubleshooting from forum posts, it was a combination of two common problems:
1) Since you could not see the 10×10 grid when you launched Spike, we upgraded your video driver.
2) The Device Manager–>USB serial converter A & B–>Advanced “load VCP” check box was checked (both converter A and converter B are part of the SA44B). You had un-checked these so your SA44B was working.
3) The “load VCP” was checked for “USB Serial Converter” (the TG44A). Once we un-checked this and power cycled the devices, everything was working.

I found this in the archives. A customer reported it worked for his 32 bit application. Let me know if it helps.

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Giorgio,
Is this a one-off project, or something you will use for many customers? Are you aware of the low latency kernel requirements?

Another issue is the driver. Is this a true x86 platform with full USB 2.0 support?

Dear G. Grasso,
These legacy APIs are no longer supported. I have had reports that the 64-bit API, when paired with a low latency kernel, works reasonably well.
Your best bet is Windows (x86/x64) which is our tried and true OS. If you must use Linux, try either the x64, or 32-bit ARM (Raspberry Pi 2-like processors).
We’ll remove the 32-bit link from our website to avoid this problem in the future.

Bbowar,

Yes, good catch. For channel power, you definitely want average+power for your video processing.

bbowar,

The algorithm is basically the same, but with the SA44B, software image and spur rejection is on by default, and this can cause inaccuracies if the signal changes rapidly. The BB60C defaults to using only hardware image and spur rejection, so it is immune from this added measurement error, and will be more accurate for dynamic, real-world signals.

[Justin Crooks]

You’ll need to download FT_PROG from FTDI. Email Justin at signal hound dot com for the xml file since I can’t upload it.

• This reply was modified 9 years, 2 months ago by Justin Crooks.
• This reply was modified 9 years, 2 months ago by Justin Crooks.

I assume you mean the FT2232H’s EEPROM?
Here is the XML file we use. Change the serial number and serial number prefix (first 2 digits of serial number) in this file, then use it to program the SA44B.

They are 50 ohms nominal impedance, but their VSWR tends to be higher than a typical spectrum analyzer. Let’s say the VSWR of your SA44B had a typical return loss of 16 dB (probably even worse than this at high frequencies). If you add a 3 dB pad to this, it increases to 22 dB, assuming it’s a good pad with excellent return loss (signal goes through pad, reflects, then through pad again). Add a good 6 dB pad, and return loss would be 28 dB. You could even try 10 dB pads, which would give you maybe 36 dB return loss, but then your signal might be noisy enough that the extra return loss isn’t worth it…

Flysight,

You can see the “typical” directivity of the ZFDC-10 rolls off to about 20 dB at around 1900 MHz, and from personal experience I can tell you it is horrible above 2 GHz. We do offer a better directional coupler that goes to 6 GHz.

That being said, there is additional impedance mismatch from the SA44B and TG44A. Adding a 3 to 6 dB pad (SMA fixed attenuator) to the SMA port of each can improve your return loss a great deal, and should get you very close to the performance of the directional coupler.

Since we do not have phase data, we cannot do an open-short-load calibration, but a good directional coupler and a couple of 3-6 dB pads should yield 25-30 dB of directivity.

tzanetos,

Thank you for contributing to the open source community. I am sure many Signal Hound users will find this useful.

That sounds like a nice solution. What voltage does your BB60C see? (available in status bar near bottom of user interface); if it’s above 4.55 volts you should be good to go.

[Justin Crooks]

Facotl,
I agree with KBONE. The frequency accuracy is 1 ppm. However, the antenna grounding, and any objects near the antenna, interact very strongly with your antenna, and can easily shift the center frequency 10% or more. By moving the antenna and changing the grounding, you can probably achieve your 433 MHz goal.

• This reply was modified 9 years, 3 months ago by Justin Crooks.

If it helps, at the most sensitive setting (-50 dBm reference level), as long as the BB60C is powered on, +20 dBm peak puts the RF power at the preamp right at its absolute maximum, and should not cause damage unless operated in this state for extended periods.
Generally, damage occurs when much larger pulses occur, or when +20 dBm is applied before the device is powered on.

That’s a good idea. A library of .csv files for the arb would be useful, especially ones that our software can’t directly produce.

Tisha,
I’ll second what AJ said, and add that your post had us all chuckling. Thanks for making our morning tech support fun 🙂

Facotl,
When using the VSG with the SA44B, you will probably want to start in real-time mode, or sweep mode with image / spur reject off (Settings menu). Then you can use a BPSK symbol rate of around 20-50 ksps. You should be able to see the modulation envelope, and measure the signal power using the channel power utility. Then you can go into modulation analysis and capture the symbols.

If you can send a picture, we may be able to help more, or you can email support at signalhound.com for further assistance.

Martin,
Thank you for the pointer. This is a great thing to check when you are having problems, as we use FTDI’s D2XX driver rather than the VCP driver. Usually, the driver installs without a problem, but when there is a problem it can be a real headache.
I’ll add this to the list of things I have customers check.

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