[Andy]

Hello Cristian
I don’t want to interrupt, but I have the SA44b running on 3.1.8 software and I see no such error. The centre frequencies and the associated errors would seem to indicate a reference frequency error.
Attached is my screen grab. Signal source is HP 8648b.
Good luck.

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[Andy]

Thanks Andrew. Yes, I can re-size the recorder window to make it (almost) disappear off the bottom of the screen and it remembers this setting. Thanks.

[Andy]

Hi all,
Just installed Spike 3.1.8 and I see the recorder is intruding in the bottom of the screen again! Thanks.

[Andy]

Hi Ron,
I’ve had the SA44b/TG44 combo for a few years and it has revolutionised my homebrewing activities. Tuning for ‘maximum smoke’ is now consigned to history and I really enjoy spur-hunting and harmonic measuring when I’m setting up a new rig. The small bandwidths available on the SA44b come in handy for sweeping filters too.
It’s amazing to see how a small tweak of (say) the post TX mixer filter or the LO injection can cause the spurs to change in amplitude over the spectrum and it’s easy to set up a rig for best cleanliness rather than ‘max out’.
I usually set myself a target of -60dBc or better for all unwanted outputs and it can sometimes be a (rather pleasurable) struggle to achieve the last few dB.
Computer here is a Win10 i5 laptop clocked at 2.8 GHz with 8 GB of RAM, but it runs almost as well on my old W7 P6200 laptop @2.1 GHz with 1GB ram.
Hope this helps. I’m sure you’ll find the SA44b very useful – and the price is right!

Andy G1HBE.

[Andy]

Ha! I never thought of pressing the same button again…must be my age. Thanks.

[Andy]

Daniel – The standalone TG is normally not something I use, but I’ve just tried it and all I did was scrub the 915 MHz out and enter 110.4 followed by ENTER. Works fine.

[Andy]

Have you tried turning off the image rejection feature in Spike? I’m assuming Bluetooth transmissions are pulsed, and that the image rejection feature is declaring the pulses as non-legit and blanking them.
That’s all I can think of!

[Andy]

Oops, forgot to say you need to engage ‘max hold’ to do this. Obvious really!

[Andy]

Catshot – before I got the tracking generator, I had some good results using manual sweeping. I used the SA44b with a Marconi 2024 sig gen, letting the analyser run at whatever rate it chose and manually stepping the generator. Sometimes I had to go over the sweep again with a smaller step size to fill in a few ‘holes’.
With careful choice of RBW and step size it is possible to get good results, but it is s-l-o-w!

[Andy]

Hi AJ.
Here’s the setup, but it happens in any setup:

CF: 401 MHz
Span: 2 MHz
RBW: 30 KHz
VBW: 30 KHz
REF: -10dBm

Input level from signal generator: -40 dBm, also at all other levels.
It’s late here, so I’ll try the 21 software tomorrow. Many thanks for the prompt attention.
Andy.

[Andy]

Looks like the supply voltage from the affected PC is too low, Bernhard.
Andy G1HBE

[Andy]

All fixed in 18, many thanks.

[Andy]

Many thanks for re-instating the 5 MHz RBW. It’s really handy for taking a quick look at what’s going on. The 250 KHz RBW caused the sweep to be too slow. Shame it’s limited to >200MHz, but it’s great anyway.

[Andy]

I may be wrong, but any version of Spike older than 3.0.12 will not work properly with Win 10. What version have you got on your laptop?
I’m sure the guys will be along later, they’ll know what’s going on.

[Andy]

Thanks for the information AJ. I doubt I’d ever use the SH as a ‘radio set’ but as usual curiosity gets the better of me.
My usual ‘quick test’ of a receiver’s VHF performance is to tune to Manchester Airport’s recorded information service on 128.175MHz AM. This is fairly weak but readable here. Here is the situation as found this morning on my various receivers:

AR5001d: indicated signal -99dBm, readable..
SDRPlay/HDSDR: indicated -60dBm (don’t know how it gets this figure), readable..
Signal Hound using Audio Player utility*: indicated -110 dBm, readable but not as clearly as the previous receivers..
Signal Hound/HDSDR: indicated -113 dBm, carrier visible but unreadable almost no audio recovered. This with RF gain at various settings..

*Set for AM, BW 8KHz

[Andy]

I use SDR# and HDSDR with the SDRPlay receiver and both give good results, so I thought I’d try the Signal Hound application. I know the SA44 was designed as a spectrum analyser (as opposed to a radio receiver) but I’m afraid I’m not impressed so far. Gain seems very low and operating the gain slider (with AGC on or off) seems to have little or no effect.
Clicking the EXT-IO button does nothing – is this correct?

• This reply was modified 11 years ago by Andy.

[Andy]

That’s great, Bruce. Please don’t forget the -ndB markers either!

[Andy]

I’d like to support Tom in his request. As a ‘quick signal finder’ the 5 MHz RBW was very handy and I too miss it. Thanks.

Andy

[Andy]

Thanks Justin.
Another question (sorry!). Over on another site, were were comparing TG crosstalk levels on another well-known analyser (Rigol). Once we’d done that, I thought I’d see what result the SH returned (should be very low level). I set up a sweep from DC to 1.5 GHz and noted the baseline noise level, but just by chance I then raised the start freq to 300 KHz and the niose level dropped by several dB. Is this anything to do with the auto-settings reducing the DC spike? Or is something odd going on?

[Andy]

Just curiosity on my part – what are the small steps in measued level at certain frequencies? I guess it’s something in the SA44b hardware, as it has always done this. See attachment. In this case, the freqs are about 80, 140 and 250 MHz.

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