Neat Benchtop Tool - Ramsey COM3 Service Monitor

[spongella]

While the term "Service Monitor" is sort of vague and non-descriptive, a service monitor is a very handy tool. I got one of these for work recently, made by Ramsey Electronics from 1987 - 2003 for routine AM/FM radio servicing. Originally selling for about $3K back in their heyday, you can get these on Ebay for a fraction of the original price. Covers 100KHz - 999.9MHz, receives/transmits AM and NBFM, counts frequency and PL tone, and has built-in 1KHz tone modulator. You can even hook up a scope for viewing of modulated signal or checking tone output. The COM3 was touted as a workhorse for the radio tech. It's bigger brother, the COM3010 has lots more options but a higher selling price.

Wondering if anyone out there has used a service monitor, what type did they use, how they used it? Want to eventually move up to the IFR/Aerotek 1200 SS after a year or two. Thanks!

 

[KE4EST]

Wow I may have to get one now. I have an old tube type that quit and never re-tubed it.
Probably a new tube or two and new caps in it and it will work again, but no freq counter and such.
Never used it for work, just for my ham radio and experimenting.

 

[lost_mesa]

An IFR use to be my daily (and favorite) service monitor, but we also had a few Cushmans and a Motorola in the shop.

The IFR had a built in scope for a spectrum analyzer display, measuring modulation, or general trouble shooting using the external probe input. A meter showed the frequency error of a transmitter, or peak modulation. It also had a tone generator for 1 kHz and PL.

While functioning as a signal generator, you could key into it and it would immediately switch to receive mode and display the power output, up to 100 watts. Unlike the Cushmans, which just blew a fuse.

Sensitivity was pretty good, maybe 1 uV. We could monitor mountain top repeaters from the shop with it, checking the frequency and modulation. Hooking a long wire to it, we could pick up WWV and zero beat the internal TXCO. The internal battery made it very portable.

This was all 30+ years ago. I imagine things have changed a little bit since then.

https://www.custom-cal.com/ModelInfo.aspx?kn=10669&m=AEROFLEX-IFR_FM/AM-1000S&srv=Calibration

 

[spongella]

The IFRs are a work of art. They come up for auction pretty regularly. Thanks for the feedback gents.