Help with IFR-1500-0102 Service Monitor

Let me make sure I understand this: You have the unit, you have the operator's manual, but you don't understand its applications?

You must not be into radio at all, because that's what a service monitor is designed for: Testing and alignment of radio transmitters, receivers, and transceivers. They most often find use in the world of commercial and amateur FM radio, from 30MHz on up through 800/900.

I've been in the business 26 years, and I've never seen one. Let's see if I can cover some of the basics.

A service monitor can be thought of as several separate instruments in one package, controlled by a common front panel. Most important among those instruments (to radio folk, anyway) are the calibrated RF signal generator and the signal monitoring functions. The generator should allow you to generate AM, FM, unmodulated CW, and possibly SSB signals on any frequency within the instrument's range.

The signal monitor function will make it possible for you to test transmitters, generally up to 100 watts output. You will be able to determine frequency error, modulation level, and an oscilloscope-like representation of whatever audio or data signal is modulating the transmitter under test.

Some service monitors also include an RF spectrum analyzer. If you're really lucky, there will also be a tracking generator to use in conjunction with it. Both features together will allow you to tune filters (bandpass, high-pass, low-pass, notch, etc.) and resonant cavities to the proper point.

There will be other functions: An internal function generator, which will probably be able to put out all kinds of sine-wave and DCS (digital-coded squelch) signals, possibly a DVM, probably a low- bandwidth (just a couple of MHz, most likely) oscilloscope, etc.

I'm speculating here because I've not used an IFR 1500. I have a

1600, it's successor. Your best source of information will be from the operator's manual you already have, and from Aeroflex (they bought IFR). Visit their site at:

...And note the contact information for the location in Wichita, KS. They will be able to provide calibration services (highly recommended, if your unit is beyond its last cal date by more than two years), spare parts, and operational advice.

What I would strongly recommend, since you seem to have an interest in radio experimentation, is to get your amateur radio operator's license. The best way to do this is to locate an amateur radio club in your area, using the resources at this link:

Once you locate a club in your area, contact them to see if they offer introductory classes aimed at getting your license. Most clubs have this at little or no cost to the applicant.

IFR makes a fine instrument, but they are not particularly cheap to repair if problems develop. Learn the capabilities and limits of your unit well, treat it with care, and it will give you many years of good service.

Happy hunting.

--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute.
(Known to some as Bruce Lane, ARS KC7GR, 
kyrrin (a/t) bluefeathertech[d=o=t]calm -- www.bluefeathertech.com
"If Salvador Dali had owned a computer, would it have been equipped
with surreal ports?"

IFR put out a detailed "how to" Application Notes for the 1500. It shows the setups for:

--Checking local oscillators & Xtals

--Measuring audio frequency response with tone sweep

--Measuring 12dB SINAD sensitivity

--Checking receiver IF bandwidth and symmetry

--Receiver RF filter alignment

--High accuracy FM deviation measurements using the Bessel null technique

--Measuring the output of very low power transmitters

--Measuring transmitter harmonics

--Stage gain measurements using the spectrum analyzer

--Analyzing receiver desense caused by intermodulation distortion

--Measuring isolation and insertion loss in Tx-Rx switches

--Synchronizing Simulcast Transmitters

--Measuring antenna isolation

--Tuning antennas for minimum VSWR

--Measuring center frequency insertion loss and 3dB points on cavities

--Transmitter cavity alignment

--Bandpass/band reject duplexer alignment

--Measuring receiver desense in a duplexed system

--Measuring receiver isolation at Tx and Rx frequencies

--Measuring Tx noise suppression at Rx frequency

The IFR part number is 1002-5001-500; it was originally printed in July

1986. I was lucky enough to get a copy from IFR for the $20 cover price but they're much more expensive (if even available) from them now...but well worth the cost. Note that the procedures listed above are not covered either at all or very well in the operator manual.

GL -- Dino KLØS/4