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 Post subject: Re: Using a Spectum Analyzer to do a visual alignment
PostPosted: Dec Sun 13, 2020 5:26 am 
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The 3336 and log amp is how I usually do filters and IF strips too. The 3336 is so easy to set up and you don't need markers.

Just for grins I looked in the XL spread sheet and as of last May I've had mine for 10 years now. That's a shocker! Pete I think you got yours about the same time didn't you?

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 Post subject: Re: Using a Spectum Analyzer to do a visual alignment
PostPosted: Dec Mon 14, 2020 8:08 pm 
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Mikeinkcmo wrote:
The 3336 and log amp is how I usually do filters and IF strips too. The 3336 is so easy to set up and you don't need markers.

Just for grins I looked in the XL spread sheet and as of last May I've had mine for 10 years now. That's a shocker! Pete I think you got yours about the same time didn't you?



Hi Mike... I am not sure when I bought it?? It was sometime after I discovered the 8165A was not what I was hoping for...
It does work amazingly well when paired with a Tek 603 display and a cheap AD device Chinese log board! Easier to setup than the Tek 497P and Tek tracking generator and a lot less risk of blowing something up! BTW, I did roach one of my AD log detector boards the other day, and I have no idea how I did it? Even a DC blocking cap didn't save the chip, but I have two new boards coming in from Amazon today. And four more from eBay but I won't see those until late January.

BTW, regarding the 8660D: yes, does get a bit of use, its frequency agility is a nice feature--I can see why Leigh raved about his unit. The HP-8665A gets turned once a month to keeps it memory battery charged, LOL!!!

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 Post subject: Re: Using a Spectum Analyzer to do a visual alignment
PostPosted: Jan Wed 06, 2021 5:34 pm 
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Joined: Oct Tue 30, 2012 12:51 am
Posts: 7
Hello
using an SA+TG for the IF chain alignment is certainly on my wish list. But I should mention that one easier application of the SA in FM alignments is to minimize the 19 Khz pilot leaking out through the outputs of most receivers and tuners. Many have pilot cancellations circuits or pilot filters with tunable coils or variable caps/trimmers with the SA you can easily tune those filters to reduce the 19 Khz present at the output.

Just FYI, I'm still trying to setup what Mike has on his website. That is a probe that has the AD8307 inside going to a my scope in X-Y mode and lightly coupling the swept input signal (10.6 to 10.8 Mhz) at different points in the IF chains.

I did buy a TinySA for 50$ but don't have any SMA connectors or attenuators to start using it in powered DUTs.

Also for those of you interested in how your FM sounds not just receives .You can also use the SA's TG to be the "audio" signal into a RF signal generator that excepts external modulation sources. Then you can see a 20hz to 20Khz sweep comes out as from your tuner. The frequency response.
Another one is to just send 1Khz tone from the TG again as the modulation source. Then see on the SA the 2nd and 3rd harmonics of that 1 Khz tone that comes out of the DUT then you can adjust your alignment to minimize odd harmonics and maximize even harmonics.
Ok ok don't flame me please, just saying what visual alignments can be done with SA and TG.

Thanks
Paba


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 Post subject: Re: Using a Spectum Analyzer to do a visual alignment
PostPosted: Jan Thu 07, 2021 5:06 am 
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Location: St. Paul, Minnesota
You can tune/align radios and antennas to an amazing degree with a spectrum analyzer, far more than is necessary, but fun to do.

The key, apart from the amply-discussed ways to protect the analyzer's input discussed above, is RBW, both capabilities (of the analyzer) and proper settings.


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 Post subject: Re: Using a Spectum Analyzer to do a visual alignment
PostPosted: Jan Thu 07, 2021 9:33 pm 
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What is RBW?


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 Post subject: Re: Using a Spectum Analyzer to do a visual alignment
PostPosted: Jan Fri 08, 2021 1:32 pm 
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(As I understand it, and I'm no expert)

Resolution Bandwidth

Think of it as the zoom control. A smaller RBW allow you to zoom in more, and see smaller spurs. (eg: 1Khz, is (probably) better than 30Khz.)


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 Post subject: Re: Using a Spectum Analyzer to do a visual alignment
PostPosted: Jan Fri 08, 2021 3:49 pm 
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Lou deGonzague wrote:
What is RBW?



Resolution Band Width determines the bandwidth, which is the ability to separate signals that are closer together.
Same as IF selectivity options in a receiver, the narrower the filter, the better the resolution of signals that are closer together.

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