Oscilloscope for 26Mhz to 500Mhz

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SpugEddy

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Why do you have to complicate things with a "reasonable question"?
The main thing I want to do is be able to test UHF and VHF
duplexers for repeaters. But since I have 10 and 11 meter radios
also, I just figured I'd get something to do the whole spread
 

N9PBD

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Because what you need is a spectrum analyzer, not an o'scope, although there are o'scopes that will function in the frequency domain, most o'scopes are time and amplitude only. Spectrum analyzers are frequency and amplitude displays.

I've got a Rigol DSA815-TG that's good from 9kHz to 1.5 GHz, with excellent specs, and it has a built in tracking generator that you can sweep diplexers with. It runs for about $1300 new, but if you look around, you can find one used for hundreds less.
 

mmckenna

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Yeah, you want a spectrum analyzer with a tracking generator.

Last one I bought was in the $17,000 range. You are probably looking for something cheaper.
 

RFI-EMI-GUY

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Looking for an O-scope to cover everything
from CB to 500Mhz, but don't know what to look
for.
Any suggestions?
Used will do just fine for me

You need a service analyzer AKA Service Monitor.

I use an HP8920B service analyzer for my radio work. It has a low frequency O'scope for audio, deviation and such, but also a tracking spectrum analyzer (Option 102) that spans up to 1 GHz. These units will do AM/FM and have a BFO for SSB demod (actually simply a BFO).

There is a Yahoo Group called HP8924 which was set up for the HP8924 model which is a larger unit and fitted for various cellular technologies. These became obsolete as Cellular technologies changed, however some models have most of the analog radio capabilities as well as Option 102 tracking/spectrum analyzer. You can pick one of these up rather cheaply, $400 to $800 or so. I would suggest reviewing the posts on the yahoo group to get a feel for the various models of Agilent/HP 8920/8924 and 8935 as well as options and service related discussions. The major issue of these are power supply capacitors that might need changing.

There are other service analyzers available cheaply, IFR Motorola, General Dynamics, Marconi, but the HP was well documented and prolific so chances of getting a good one and keeping it running are most promising.
 

RFI-EMI-GUY

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You need a service analyzer AKA Service Monitor.

I use an HP8920B service analyzer for my radio work. It has a low frequency O'scope for audio, deviation and such, but also a tracking spectrum analyzer (Option 102) that spans up to 1 GHz. These units will do AM/FM and have a BFO for SSB demod (actually simply a BFO).

There is a Yahoo Group called HP8924 which was set up for the HP8924 model which is a larger unit and fitted for various cellular technologies. These became obsolete as Cellular technologies changed, however some models have most of the analog radio capabilities as well as Option 102 tracking/spectrum analyzer. You can pick one of these up rather cheaply, $400 to $800 or so. I would suggest reviewing the posts on the yahoo group to get a feel for the various models of Agilent/HP 8920/8924 and 8935 as well as options and service related discussions. The major issue of these are power supply capacitors that might need changing.

There are other service analyzers available cheaply, IFR Motorola, General Dynamics, Marconi, but the HP was well documented and prolific so chances of getting a good one and keeping it running are most promising.

This excellent site describes the various models. And should it concern you, they do operate well below 30 MHz with some slight degradation. They will work fine for CB and Ham HF radio work.

Differences between the HP 8920A, 8920B, 8924C, E6380A, E8285A

http://www.amtronix.com/e6380a.htm
 
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RFI-EMI-GUY

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Thank you Guys. I appreciate the help.
At least now I'm on the right path.

1 more question, will I also need a frequency generator?

To test and tune receivers yes. To test and tune duplexers yes!

If you buy a system analyzer / Service Monitor it is built in. The HP's have ability to generate test tones, AM and FM deviation, a variable attenuator for receiver sensitivity and a SINAD meter for qualitative measurements. In the tracking mode , for sweeping filters and duplexers, the generator tracks right along with the spectrum analyzer or can be set to an offset if sweeping receiver mixers, frequency translators and such.

Here is a comprehensive operators manual:

https://literature.cdn.keysight.com/litweb/pdf/08920-90126.pdf?id=1000001759-1:epsg:man
 
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mmckenna

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Thank you Guys. I appreciate the help.
At least now I'm on the right path.

1 more question, will I also need a frequency generator?

A service monitor will have one built in. A spectrum analyzer often will need to have it ordered as an option, usually referred to as a "tracking generator", as it can be set up to track the input frequency settings of the spectrum analyzer.

A service monitor, if you can get one at a good price, is a useful tool.
A spectrum analyzer with a tracking generator might be cheaper, and will give you what you need to set up duplexers, but the service monitor will let you do more.

If you are buying a used one, try to find one with a recent calibration date.

Make sure you get a good set of test cables for whatever you choose.
 

AK9R

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I would suggest reviewing the posts on the yahoo group to get a feel for the various models of Agilent/HP 8920/8924 and 8935 as well as options and service related discussions.
I have an HP 8920A which is what gets lugged along when I visit a repeater site for maintenance. It does everything that I need to do: transmitter frequency error, transmitter power output (up to the input limits), transmitter deviation, receiver sensitivity, duplexer tuning, and system desense.

That said, I also bought a Rigol DSA815TG. It is much easier to use, in my opinion, for duplexer tuning and it has more measurement and display features. I also use the Rigol in demonstrations of transmitter spurious emissions. The big advantage to the Rigol over the HP 8920 is that it is lighter (9 lbs vs 38 lbs).

In my opinion, it all depends on what the OP wants to do. If he's just tuning duplexers, a spectrum analyzer with tracking generator is the tool to use. If he wants an all around two-way radio service instrument, a service monitor is the answer.
 

prcguy

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A service monitor with tracking generator will help you align a duplexer but its fairly crude compared to an actual spectrum analyzer with tracking generator. With an HP or similar spectrum analyzer I can tell you within a tenth of a dB or better how a duplexer is performing and with most spectrum analyzers built into a service monitor you are lucky to know within several dB at best.

But, a service monitor with spectrum analyzer is a really handy tool and hard to beat for all around radio tinkering and repair.
 

RFI-EMI-GUY

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At the end of the day, once you have tuned the duplexer, you still need the system analyzer (aka service monitor) to perform repeater desense testing and noise floor testing.

The 8920, does have A/B settings to normalize the tracking baseline and you can expand the vertical resolution to get the last dB from the bandpass or notch. But admittedly It is fiddly compared to a dedicated spectrum analyzer with tracking.

What I have done is used the presets extensively so I can recall various modes of operation in the manner that I am familiar with. Reading the manual is very important with the 8920. Coming from using Motorola R2008D , which was a very simple device (now functionally obsolete) to using the 8920B was a big learning curve because the 8920B is so much more versatile. It is really a back end for computer automated radio testing that happens to have a man machine interface.

With the presets, I can go from tracking generator to receiver testing, to transmitter testing with a button press, knob twist and knob push.

For a bench instrument, it really simplifies the amount of gear needed.

Sent from my SM-T350 using Tapatalk
 
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SpugEddy

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So after looking and searching for a used Spec Analyzer
the first question that comes to my mind is, "What the hell
do you guys do for a living that you can afford one of these?"

I'm actually seeing used ones for $99k. Just a shot in the dark
here, but I'm assuming there is no such thing as the Dollar General
model. What is the average used price of a lower end that will do
what I'm looking for? Remember, this is just a hobby for me, not a
profession.
Suggestions please
 

AK9R

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As previously mentioned, the Rigol DSA815-TG is a decent spectrum analyzer with included tracking generator at an affordable price. It's not a $50,000 HP/Agilent/Keysight unit, but, for tuning duplexers, it's very easy to use and does a good job, in my opinion.

https://www.rigolna.com/products/spectrum-analyzers/dsa800/

The new price direct from Rigol is $1300 right now.

Finding a service monitor, like an HP 8920, HP 8924, IFR 1200, IFR COM 120, Motorola R200?, etc., at a reasonable price means that you are going to be looking at the used market because none of those have been made in a while. Amtronix has some used but working and calibrated HP 8920Bs for $3900-4500. I got a great deal on my 8920A by taking a chance on an online seller who looked a little shady, but I got a working unit with an out of date calibration for $1500 plus shipping.
 

RFI-EMI-GUY

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As previously mentioned, the Rigol DSA815-TG is a decent spectrum analyzer with included tracking generator at an affordable price. It's not a $50,000 HP/Agilent/Keysight unit, but, for tuning duplexers, it's very easy to use and does a good job, in my opinion.

https://www.rigolna.com/products/spectrum-analyzers/dsa800/

The new price direct from Rigol is $1300 right now.

Finding a service monitor, like an HP 8920, HP 8924, IFR 1200, IFR COM 120, Motorola R200?, etc., at a reasonable price means that you are going to be looking at the used market because none of those have been made in a while. Amtronix has some HP 8920Bs for $3900-4500. I got a great deal on my 8920A by taking a chance on an online seller who looked a little shady, but I got a working unit with an out of date calibration for $1500 plus shipping.

Nobody is paying $99K for hobby equipment!

I got my 8920B ~14 years ago, from a comm company in Lynchburg. Mine was surplused from the Ericsson factory when they closed up some cellular manufacturing and had spent its life in a clean test lab, installed in a rack. I paid over $4,000 with a 5 day return option. I am happy with it. That unit new was around $25K.

Around the same time, the company I worked for was seeking one with a warranty and they were over $10,000 from one of the famous test equipment companies. The one that persistently sent out green colored mailers. That vendor could not provide a working unit and the calibration certificate was apparently bogus as it would not accept high power without going into alarm. My employer ended up with a low end Motorola - General Dynamics monitor R2590 that was brand new but very buggy.

Fast forward several years and the market flooded with HP8924's going for a few hundred dollars.
 
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