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 Post subject: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Mon 06, 2021 2:53 pm 
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Hi guys! I'm new here so please be kind :shock:

I'm trying to understand benefits of spectrum analyzers and should I consider buying one.

While researching these things I ran into this - "Handheld Spectrum analyzer by SAF Tehnika"
Can anyone explain to me please, how serious this equipment is and what is it used for? Also I'm wondering is it really the worlds first handheld spectrum analyzing device?


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Mon 06, 2021 3:50 pm 
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You left out an important word in the product description. They claim to be the first handheld microwave spectrum analyzer. That word ups the price an order of magnitude and some of those models go above 80GHz. Lots of cheap handheld SAs available on ebay, banggood or alibaba but they typically only go up to 1GHz, more or less.

If you have to ask why you would need such a tool, you probably don't :D


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Mon 06, 2021 4:06 pm 
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Not to be snarky or mean, but if you don't know what you would use it for, you probably don't need it. (Sorry, I was composing this as Paul posted his reply). A spectrum analyzer is a device that gives a graphical representation of frequency on the X-axis versus signal amplitude on its Y-axis. Basically a sweep oscillator and a mixer combined to show you the spectrum of a particular signal or range of signals. Of course this can be very useful in some fields; communications services like cellular providers, satellite services, broadcasters, two-way radio companies, and even some amateur radio operators use them to check on their signals. They figure prominently in research labs and even some advanced experimenters and hobbyists use them. But do you need one to fix an antique radio? Most emphatically not!

SAF Technika did not claim to be the first handheld spectrum analyzer, BTW. There have been many others going back at least 20 years. What they are claiming is the first handheld spectrum analyzers to cover the V and E microwave bands (56-67 GHz and 70-87 GHz respectively). These frequencies are a "brave new world" just now being opened up for short range communications. The company does make some models which will work as low as 300 MHz, but it appears their main business is in microwave technology.

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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Mon 06, 2021 6:42 pm 
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Just to expand on Chris's point a bit

A spectrum analyzer is basically a sensitive calibrated wide band receiver that will show you the presence, frequency and strength of signals (usually RF, but available for audio frequencies as well) across a band of interest. You can use a sound card in a PC along with some software for an audio spectrum analyzer. Generally, the higher in frequency you go the more it's going to cost you. A decent SA coupled to your TV antenna along with a chart of channels could give you an idea of what TV stations are available in your area (although in the digital age this is not as easy as you would think).

There are software defined radios (SDRs) that can be used with a PC for use as a basic spectrum analyzer. I used one to build a TV spectrum analyzer but because of the way they are built, signal amplitude values are not really calibrated relative to anything you can use. Still, pretty cheap, you can get one for around $20 and there are a lot of different software packages freely available. Fun to play with.

A more useful instrument for the RF hobbiest is a VNA which is essentially a spectrum analyzer coupled to a swept RF source. You can use a VNA to develop RF amps, filter networks, antenna matching and numerous other RF tasks that are nearly impossible otherwise. Some of this can be accomplished with an SA coupled to tracking generator, but a full VNA is more useful. These are absolutely required for doing microwave development. These are usually pricey, but there's a micro VNA floating around that gives you a lot of bang for the buck.

And these have nearly zero application for antique radios (I would say zero, but if you have one of these you tend to come up with creative uses for them)


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Mon 06, 2021 8:57 pm 
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To overly simplify it for the novice.... an oscilloscope gives you a visual display plotted as amplitude vs time. The spectrum analyzer gives you a display of amplitude vs frequency.

Both instruments are powerful tools that do completely different things.

You really don't need either for working on radios, although a scope can assist a technician that knows how to use it, and in combination with a sweep generator can be used for tuning the various stages.

Using a spectrum analyzer to work on radios is something like using an A-bomb to dig a fence post hole ;-)

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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Mon 06, 2021 9:23 pm 
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This is the original poster's first post. Hence I suspect the question is about spectrum analyzers, not antique radio.

Spectrum analyzers were traditionally very expensive. But for almost fifty years there have been projects under that title, of varying performance. Lots built with tv cable tuners, some not amou ting to more than a scanner radio with a visual output. Some more serious, with good IF filtering, and anattempt at logarithmic display, but those tended to have limited range.

Now we have cheap pocket spectrum analyzers, that have limitations. Since they are cheap, they suddenly "make everyone an expert".

One of the better articles I ever saw was a project by Wayne Ryder in Ham Radio, I think 1977, in Oct or Nov (the annual receiver issue). It's a project, but he goes into some of the tradeoffs. I can't help but feel that some buying those tiny and cheap spectrum analyzers have bypassed such articles.


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Tue 07, 2021 7:45 am 
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Barry H Bennett wrote:
Using a spectrum analyzer to work on radios is something like using an A-bomb to dig a fence post hole ;-)


Well said, I see now.


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Tue 07, 2021 3:23 pm 
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I had, before I retired, been in the radar maintenance business for about 40 years. I have needed a spectrum analyzer about a dozen times. Been about a dozen more when they have come in handy. However, when you need one, you really need one and nothing else will do.

John


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Tue 07, 2021 9:54 pm 
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"Handheld Spectrum analyzer by SAF Tehnika"

Definitely not a spec/an that I'd use for broadcast radio work. I wouldn't even use for the RF stuff I do work on.

RBW and VBW suck on that thing for the price.


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Wed 08, 2021 1:07 am 
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xwarp wrote:
"Handheld Spectrum analyzer by SAF Tehnika"

Definitely not a spec/an that I'd use for broadcast radio work. I wouldn't even use for the RF stuff I do work on.

RBW and VBW suck on that thing for the price.


Good call on the value equation of that particular spec an. They aren't necessary, but they are fun. This forum topic is defined as being for things that could be used to work on antique radios.


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Wed 08, 2021 2:18 pm 
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How serious is this equipment? I would rate it as above undergraduate level in the hobby category. But as they have become much more affordable to the working man, more are experimenting with them and exploring their uses in the electronics shop and ham shack. Like a lot of tools, they have many uses and there are many different types of SA's.

I never really know what I save these pictures for, now I guess I know why ;)

Here is more or less a standard RF spectrum spectrum analyzer looking at a transmitter's carrier and sideband signals. This was done in a hold mode to see all three signals together.

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Here is an RF spectrum analyzer in scalar network analyzer mode, using its tracking generator to look at the swept response of a filter.

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Here is a specialized spectrum/network antenna analyzer being used to look at antenna return loss in the 40m ham band.

Hope this gives you a clearer idea of the practical hobby uses.

-Mark-


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Wed 08, 2021 6:37 pm 
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A cheapy is also good for finding RFI in or around the ham shack.

John


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Thu 09, 2021 7:01 pm 
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Barry H Bennett wrote:
Using a spectrum analyzer to work on radios is something like using an A-bomb to dig a fence post hole ;-)


And just what do you imagine the spectrum analyzers were invented to work on then? I have been working on radios for over 45 years. Within one week of hiring on at Motorola I was taught to use a spectrum analyzer. I have been using them ever since and have lost count of the number of times they proved to be indispensable. The one on my bench at work right now is the most used instrument that I have other than a power supply.

No, you don't need one for this hobby but even here the difference is not akin to that between an A-bomb and a post hole digger. It is much more like the difference between a Model-T and a Tesla. Both will get you there, both have their charms, and the Model-T may even be more in the spirit of things. The Tesla is very nice too however and it is hardly overkill.

If you want to play with one you can get a TinySA for $55 (and probably sell it for $30 if you decide it is not for you):

http://www.randl.com/shop/catalog/product_info.php?products_id=75243&osCsid=ha9cd162ojp4v041la6a18bv47

I don't have one, in fact I just bought a new Siglent SA but this should do enough for you to tell you if you want a better one or want one at all. You don't have to have one for this hobby but that does not mean they are useless to have.


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Mon 13, 2021 2:58 am 
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Greetings to Robb and the Forum:

I'll put my $.02 worth in just to muddy the waters.

Spectrum analyzers are just what the name implies.... gadgets that allow one to look at a spectrum of frequencies to see if there is anything there that should not be or if there is anything missing that should be there.

For the antique radio hobby, a spectrum analyzer is of limited utility. It can be used to look at a local oscillator in a superheterodyne receiver to see if the oscillator is running where it should be and not oscillating on more than one frequency at a time. It can also be used to perform IF alignment, provided that it is equipped with a tracking generator. There are lots of less expensive ways to do IF alignment, however, so a spectrum analyzer is overkill for that application. However, if you have one that covers the IF frequencies you are working with, then it is quite convenient and simpler to set up than a sweep generator and oscilloscope combination.

Spectrum analyzers really come into their own when working on transmitters. Before I retired, I was a broadcast engineer and I used spectrum analyzers almost daily. Now that I am retired, I still work on ham transmitters and take care of a low power FM radio station, so my spectrum analyzer sees frequent use.

For transmitters, some of the things that you need a spectrum analyzer for are:

1. Setting FM deviation using the Bessel null method.

2. Looking for spurious emissions and harmonics in a transmitter output and verifying that the transmitter meets specs and is legal.

3. Examining transmitter frequency response using an additional gadget known as a "Sideband Analyzer". This is an absolutely necessary technique for aligning NTSC transmitters, which have to be aligned much the same as TV receivers do. A lost art now, but I did a lot of it in times gone by. I built my own sideband analyzer for examining frequency response of ham radio SSB transmitters... a very handy measure of microphone to antenna performance.

4. With a return loss bridge, antenna performance can be examined (turns the spectrum analyzer into a scalar network analyzer as mentioned in a previous post).

5. Filter response can be examined (assuming you have a tracking generator) and tunable filters including diplexers and signal rejection cavities can be adjusted for correct operation.

Since I do a lot of this stuff, I wouldn't be without one.... but whether or not you need one is, like most engineering problems, is a cost vs. benefit trade-off. If you plan to do some of the things I mentioned, then you definitely need one. If you have never heard of these applications, then you probably don't.

Good Luck,

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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Mon 13, 2021 4:20 am 
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I couldn't resist putting in my opinion. I own two and a half spectrum analyzers. (One is a digital scope with FFT.)

As far as I am concerned, a spectrum analyzer is one of the most fun pieces of equipment. I play with mine all the time because it's fun to look at modulated signals, to see distortion products, to measure frequencies, and more. Now that makes me a true nerd I guess but I do get a great kick out of seeing spectra and the like. Measuring modulation, AM or FM, is fun. I even used it yesterday to troubleshoot a garage door opener, which turned out to need a new battery. If I can set up an SSB transmitter with tone modulation I can measure unwanted sideband and carrier suppression. I see how much distortion my fancy signal generator has. (I got rid of all my low grade sig gens so I got myself out of having to see how poor they are. Well I still have one but it's in the garage so I don't play with it.)

I remember when a ham visited and I showed him spectra of various modulated waves and he was dumbfounded to see on the screen exactly what the books showed.

No, I don't need a spectrum analyzer, but I certainly am happy to have them.


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Wed 15, 2021 12:38 am 
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bob91343 wrote:
I couldn't resist putting in my opinion. I own two and a half spectrum analyzers. (One is a digital scope with FFT.)

No, I don't need a spectrum analyzer, but I certainly am happy to have them.


Well said, I couldn't agree more.

Erik K


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Wed 15, 2021 9:11 pm 
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Location: Oklahoma
Greetings all,

A bit late to the post... we have a pair of "SAF Tehnika handheld spectrum analyzers" that we use at work. They are designed for aligning microwave dishes on tall towers.

A climber/technician can climb up on both ends of a microwave shot (dishes installed) and align the dishes exactly (without radios), and measure the link (air) loss, to see if we are getting design spec's. They really are a time saver.. before these, we would align dishes to the best of our ability, and they still would not perform to spec.. apparently we were aiming one or both ends to a side lobe or reflection. We have spent days trying to align dishes, with no luck.. 5ghz, 11ghz, and 18ghz are our most common. Additionally, the larger and higher gain, better spec the dish, the harder that it is to aim. Short shots may use 2ft dishes.. longer shots 4ft, 6ft etc.

Imagine aiming a laser at a dish, and you have to hit it exactly.. a bull's eye (at 5 to 20 miles). That's what it takes... if off, even the least little bit, you will not get full modulation thru the link, and will also be more susceptible to rain/snow/fog fade. The SAF radios are amazing.. I'm not sure what the bandwidth is on the latest models... but we have links that push around 2Gb of bandwidth thru the air, with latency of less than 1ms.

These analyzers come with adapters and cables to connect to most major manufacture's antennas. The radios mount directly to the antenna.. then are fed with fiber for data and copper for power.

If you want to get your heart rate up... google "SAF Tehnika handheld spectrum analyzer", the hit the "shopping" tab. Our guys climb with these... needless to say, they have lanyards on them and are rigged where they will not drop them!

I'm no expert.. just my experience with OP's posted subject.

73's
Robert


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 Post subject: Re: SAF Tehnika handheld spectrum analyzer
PostPosted: Sep Wed 15, 2021 10:51 pm 
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Somehow the idea of lugging an HP 141T up a tower brings up all kinds of mental images...let alone a 300' extension cord lol. I don't know how we ever made do without modern electronics :) Ahhh t he good old days. When a lab grade signal generator took up half the bench and weighed 75 lbs....

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