[R-390] Spectrum Analyzer

[Shoppa, Tim]

At the very low end of sweep generators, anything from a TV/radio service shop disposal sale will be cheap and servicable.

Brand names may go from Eico to Heathkit to RCA to Sencore to B&K. You should not have to pay more than $10-$30.

These are not fundamentally hi-precision lab instruments but will be great for alignments etc. And the fact that they are not hi-precision lab instruments means that you can go inside and fix them without any fear.

There are better ones that show up on the surplus market, surplus from VHF/UHF mobile radio servicing, that are approachable too.

I also recommend any of the very low end benchtop HP Wien bridge oscillators (200CD, 202C, etc.) from either the tube or solid-state era. They all cover 455kHz and have very nice verniers and are very very cheap but simple and solid instruments. E.g. I know how to repair one of those but do not know how to repair a fancy-pants HP spectrum analyzer ☺

I am of a mind, when it comes to test instruments, that I should never have to worry about having to fix them. They should all be so solid and easy to repair that they should last forever. I would rather use reliable and simple stuff to repair radios, then worry about repairing lab quality instruments that are way more complicated than my radios.

Tim.

From: Ben Loper [mailto:brloper at gmail.com]
Sent: Monday, March 14, 2011 10:17 AM
To: Mark Johnson
Cc: Shoppa, Tim; r-390 at mailman.qth.net
Subject: Re: [R-390] Spectrum Analyzer

I wanted a sweep generator because I thought it would be more useful, this thing just happened along.  Any recommendations on a good inexpensive sweep generator?
On Mon, Mar 14, 2011 at 9:03 AM, Mark Johnson <mvjohn at sympatico.ca<mailto:mvjohn at sympatico.ca>> wrote:
I have an older HP spectrum analyzer; got it cheap, and use it for looking at transmitter outputs - harmonics etc.

I bought some good quality RF attenuators; expensive little beastie's, that allow me to reduce a typical 100 watt transmitter down to a few milliwatts, then feed directly into the spectrum analyzer. Gives a nice view of the signal output. I agree with the previouse posting - if i had to prioritze, I'd keep my O'scope and sweep generator before the Spectrum analyzer....

Mark V Johnson VE3DJU/VE3LU

> From: tshoppa at wmata.com<mailto:tshoppa at wmata.com>
> To: brloper at gmail.com<mailto:brloper at gmail.com>; r-390 at mailman.qth.net<mailto:r-390 at mailman.qth.net>
> Date: Mon, 14 Mar 2011 09:23:51 -0400
> Subject: Re: [R-390] Spectrum Analyzer

>
> Many surplus spectrum analyzers are not (by nature) HF spectrum. Many of the ones you'll see on the surplus market are VHF/UHF range. They can be adapted to HF with an upconverter.
>
> If you want to see how squirrely a typical 40's/50's/60's/70's ham transmitter looks during keying it might be of some use :-). Most likely, you do not want to know! Almost all screen tube PA's and drivers of that era will show some parasitic oscillation during keying.
>
> For receiver alignment etc. a sweep generator is far more useful than a spectrum analyzer. Here on this list we tend to focus on the lab-type HP equipment but realistically a Sencore-type TV/Radio service shop-oriented unit will do fine.
>
> Tim.
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net<mailto:r-390-bounces at mailman.qth.net> [mailto:r-390-bounces at mailman.qth.net<mailto:r-390-bounces at mailman.qth.net>] On Behalf Of Ben Loper
> Sent: Monday, March 14, 2011 9:15 AM
> To: r-390 at mailman.qth.net<mailto:r-390 at mailman.qth.net>
> Subject: [R-390] Spectrum Analyzer
>
> I found a good deal on a spectrum analyzer, but I'm wondering how much use
> it will be working on boat anchors. Are there many alignment procedures
> that would benefit from a spec analyzer or should I pass on it.
>
>
>
> “A fire has burned my hut to the ground -- how much better to see the moon!"
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“A fire has burned my hut to the ground -- how much better to see the moon!"