Don't know. Never had occasion to use or look inside a SM-230. My experience is limited to the SM-220. Perhaps someone else on this list has the info you need. However, all that being said, it would not surprise me if the band-scope option used the same module for both units. If the SM-230 used a module called the BS-8, it is possibly the same unit. If the part number is different, then some more examination would be needed.
Keep in mind, however, how the band scope works. It is basically an electronically tuned receiver that derives its tuning voltage from the horizontal sweep oscillator in the band scope - which at root is basically an oscilloscope. The sawtooth signal from the sweep oscillator drives a varactor (voltage variable capacitor) diode connected to the tank circuit of the BS-8 oscillator. The oscillator then sweeps back and forth around the 8.83 MHz IF, either plus or minus 20 kHz or plus or minus 100 kHz, depending on the bandwidth selected. The BS-8 oscillator signal is mixed with the 8.83 MHz IF signal from the radio, resulting in a new IF (for the band scope only) that is amplified and detected, then sent to the SM-220 (or SM-230) vertical amplifier. The resulting varying amplitude signal then corresponds approximately to the level of any signals present , which then appear as "pips" on the spectrum-display screen. Most all spectrum analyzers work this way, at least the "conventional" analog types. The Elecraft P3 is probably rather different in how the detection and display process is implemented, but remember it has access to a whole box full of software tools that the older SM-220 and SM-230 do not have. In order for the SM-220 or SM-230 to display signals from the K3, or any other transceiver, all that is needed is for the band-scope oscillator to be able to sweep back and forth within the desired offset from the transceiver IF, and for the band-scope unit's "front end" to be able to tune to the desired transceiver IF. Everything else from that point on is pretty much independent of what radio it is connected to . Some band-scope adaptors don't even have a tunable RF front end, instead they rely on the transceiver's signal processing circuits to provide the needed selectivity. Spectrum analyzers and band scopes are essentially the same animal. A basic display is easy. The hard part comes when you want precise sweep linearity, exact amplitude calibration, and the ability to separate and measure "close in" components of modulation products. Those last items are the reason that -hp- (Agilent), and other high end test equipment manufacturers can command prices of $15K to $50K for their instruments. For example, consider the measurement of a 1.2 GHz FM signal from a data transceiver that I work on from time to time. I happen to have a Tektronix spectrum analyzer that will display discrete modulation sidebands that are only 50 Hz apart, and measure their exact amplitude and frequency offset from the main carrier. It is however, rather bigger than a breadbox, and it costs a bit more than the SM-220. - Jim, KL7CC Radio Amateur N5GE wrote: > On Sun, 10 Oct 2010 13:58:20 -0800, Jim Wiley <[email protected]> > wrote: > > Hello Jim. > > I have a Kenwood SM-230. I wonder if the same holds true for that > model? > > Tom Childers, N5GE > Licensed since 1976 > QCWA Life Member 35102 > > [email protected] > http://www.n5ge.com > http://www.swotrc.net > > >> Open up he SM-220. The band-scope option is in a small metal box toward >> the rear of the scope. It will be marked either BS-8 or BS-5, for 8 >> MHz or 5 MHz respectively. It may be possible to retune the unit to the >> desired operating range, although it may be necessary to juggle some >> component sizes. A schematic can be obtained on line I think. Note: if >> it is a BS-5, the only difference between the units is the oscillator >> coil and a few components. Replacing the appropriate parts with those >> for the alternate frequency range will make the switch. Since these are >> "discrete" parts, the swap should be straightforward. The 8 MHz version >> may have enough tuning range to shift over the K3 IF without changing >> parts. As supplied, the BS-8 is set for use with an 8.83 MHz IF, if I >> remember correctly. The band-scope print is part of the main SM-220 >> manual. . >> >> >> - Jim, KL7CC >> >> >> DM4iM wrote: >> >>> Elecrafters, >>> i like to interface a Kenwood SM220 Scope to a K3. >>> There is a Pan Display Option installed, but there is no hint >>> if it is the BS-5 (3.3Mhz IF) or BS-8 (8.83Mhz IF). >>> How can i determine which Pan Display i have? >>> I got this scope from a SK w/o any manuals. >>> If it is the 8Mhz IF, can i retune it AND will it work with a K3 / >>> KXV3A ? >>> >>> >>> >>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
