Service Monitor Recommendations

This forum exists for the purposes for discussing service monitors (This includes but is not limited to Motorola, HP, Aeroflex, GD, etc). Additional topics allowed include test procedures, interpretation of test results, where to find information about specific tests, antenna VSWR, return loss testing, duplexer and filter alignment, etc.

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iamspt
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Service Monitor Recommendations

Post by iamspt »

Hi all. Thanks to everyone for sharing knowledge here. I often spend many hours a week researching and reading the wealth of information. over the years i have learned a ton.

I finally graduated from school (electronics engineering) and gainfully employed in the field. I am a ham radio operator and LOVE 2 way radio.

From a hobbyist perspective, I would like to delve into transmitter/receiver alignment, repeaters, tuning duplexers, perhaps sweeping antennas and feedlines. My interest lies in 440 and 900 at this time. Although i have a steady check, i dont have a whole let to spend so would like to spend wisely.

There are many ways to skin a cat...having said that im thinking i'd like to get a service monitor. obviously some like the IFR 1200/1500 has many built in features but come at a cost vs some of the service monitors that cover 1K to 1G + with spectrum analyzer but are meant for cell systems and are much less expensive.

If it were you, which route would you go? how can I achieve my goal the most cost effective way possible? What features are important to you when thinking about what Id like to use it for? Are there specific models you would recommend?

I look forward to everyones input. THanks!
Jim202
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Re: Service Monitor Recommendations

Post by Jim202 »

I don't have a straight answer for you, but will pass along my personal use of a number of different service monitors. On point I will give you is to shy away from the HP units. They tend to be an over kill and takes an engineering course to make them play correctly. If you don't get all the filters and other selections set correctly, you modulation readings will be wrong. I use to have a cheat sheet with the service monitor just to make sure it was set up properly. Without the sheet, I would always miss one of the settings and when trying to measure deviation, would get an incorrect reading.

The IFR 1200 and 1500 are good boxes. Just remember that there is little repair service available for them. I own a 1200 and the high voltage supply died many years ago. No replacement transformers available, so I lost the use of anything on the CRT.

You might even consider an IFR model 500 if all you want is frequency and deviation measurements. They are small and low cost.

Jim
GlennD
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Re: Service Monitor Recommendations

Post by GlennD »

I own and have intensively used an HP but I have switched to a Motorola 2001D. The HP is a great box but the 2001 is much more 2 way service orientated. I also have an IFR 1500. They all do the job and except for tracking I like the Motorola best. I have a Tek 495P and a matching TR503. It is far superior to any service monitor for tracking. I also have had two IFR 1600s. They are fine but very heavy.

What can I say, I am a service monitor freak!
GlennD
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Re: Service Monitor Recommendations

Post by GlennD »

The nice thing about the 2001D is that they are available on Ebay for under $1000. Only get the D model. It is a bug fixed unit and very different than the A-C units. There is a whole series of units with different options. For example the 2008D has analog cellular built in.
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fineshot1
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Re: Service Monitor Recommendations

Post by fineshot1 »

Yes - i am a ham fella also and because of my needs right up into the 1.2ghz band there was no other option that i could afford so i picked up a IFR 1900csa from a local reputable seller with a limited warranty.
fineshot1
NJ USA
iamspt
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Re: Service Monitor Recommendations

Post by iamspt »

Anyone else want to offer a suggestion of what models are good and maybe ones to stay away from?

Can the models made for cell service work on for what I'm looking to do or do they not okay well on fm?

What features are must have? What features are better to have in a stand alone unit rather than wrapped up in a huge bundle?

Thanks for everyone's input thus far
jry
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Joined: Fri Feb 06, 2004 3:14 pm

Re: Service Monitor Recommendations

Post by jry »

Picking this type of test equipment is really dependent on your requirements and figuring that out is what you really need first. One of the first items is your price range since you can really find units from a few hundred to 10's of thousands of dollars

Often times you may be better served by acquiring discreet pieces of equipment vs. one service monitor which is really intended for field technicians or at best bench production technicians servicing just two way equipment.

The HP models ( HP made a lot of stuff ) used as Service Monitors were targeted toward a more engineering or manufacturing environments and are very accurate, easier to automate and flexible but not as easy to use as some of the less sophisticated less capable monitors. Good news was that the core design was leveraged in a number of products and there are literally tons of parts and information to support these.

Some of the service monitors referenced only had bandwidth switching to allow for low,medium and high levels of modulation measurement and came from the era of analog only and crystal controlled radio sets. The ones referenced were really designed for the radio systems in the 80's at best and the requirements were pretty simple but still work for analog radio systems today

in later versions even the Motorola 2001D and IFR 1200 Super S included audio filtering and bandwidth to provide higher accuracy and also eliminate some of the higher frequency synthesizer noise/ jitter in later radios. Not sure that many people still using these units even use these filters since it requires going into menus that are not all that obvious.

For later service monitors this type of audio filtering and bandwidth for modulation control is standard ..the IFR COM-120 added a whole screen for configuring filters and was the next generation after the 1200 1500 and Motorola R2001D

For aligning later digital radios these early service monitors would not be accurate enough and you do have to have the correct audio ranges to do this correctly , These alignments also referenced using an HP modulation analyzer with correct audio filters as one of the primary tools.

One of the distinct advantages of using the HP type test equipment is that it automatically finds the TX frequency which is extremely useful when aligning the radios which have at least 6 alignment points and often more. The only thing better is to have a later service monitor with and AutoTest capability which automates the entire process ( well beyond what you need though )
The other service monitors will often use a scan like functionality to emulate this but its usually pretty slow in comparison.
iamspt
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Re: Service Monitor Recommendations

Post by iamspt »

Jry, thanks for your thoughts...

Keeping in mind what I plan to do as outlined in my original post, what individual components would you purchase?

A genuine thank you to everyone. I really do appreciate y'all...
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Wowbagger
Aeroflex
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Re: Service Monitor Recommendations

Post by Wowbagger »

The COM-120B can also do a TX frequency search (it's under the Spectrum Analyzer screen). It also supports automation - there are applications for it that will automate testing a radio across multiple TX and RX frequencies.

One key feature to look for is a tracking generator (if the unit has a spectrum analyzer) - without that you cannot easily tune filter cavities. Having the ability to offset the tracking generator from the analyzer center frequency allows checking IF mixers.

Also, look at the power handling - some units cannot handle more than a watt of input power, while others can handle significant power (albeit for short durations).
This is my opinion, not Aeroflex's.

I WILL NOT give you proprietary information. I make too much money to jeopardize my job.

I AM NOT the Service department: You want official info, manuals, service info, parts, calibration, etc., contact Aeroflex directly, please.
jry
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Re: Service Monitor Recommendations

Post by jry »

SO the discreet test equipment would be
1. signal generator to at least 1Gz ...needs to have the modulation that you want but AM/FM is typical
2. Spectrum Analyzer ....tracking gen option would be great but at least 1Ghz if not more
3. Modulation Analayzer - may need an external high power attenuator ...usually not a bad idea for any service monitor for extended high power transmit. The 8901B can adjust for external gain or loss with a couple of buttons. Automatically tunes to TX ...8901A is close but the 8901B is a more improved and has additional functionality.
That would be a start ...what you are trading off is having a far more accurate set test equipment vs one service monitor that is reasonably accurate but more focused on two testing so you have things like built in paging ,DTMFand DPL signalling along with SINAD and in a single potentially very portable instrument.
I use both discreet instruments for the bench and a service monitor in the field primarily but for some bench two work as needed.
One other quick note is the HP stuff is built like a tank . I have an 8901B that is still in fantastic shape ...everything does wear out and fail overtime but HP will last longer than most. I do own a pretty diverse set of instruments so I am no where near exclusive to just HP/Agilent/Keysight.
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