On Sun, 10 Oct 2010 15:02:10 -0800, Jim Wiley <[email protected]> wrote:
Thanks, Jim. I suspect the SM-220 and SM-230 are pretty much the same. I've had this SM-230 since I bought a TS-950s in the mid 80s and have used Panadapters of one kind or another since then. I went to the Belton, TX ham fest last weekend and saw an SM-230 for sale. It was mint and the guy wanted $600 for it. Now if I can sell mine for that I can get a P3 ;o) Once again, thanks for the comments. 73, Tom, N5GE K3 #806 with SUB RX, PR6, KRC2 and K144XV K3 #1055 with PR6 and XV432 W1, 2 W2's and other small kits QCWA Life Member 35102 [email protected] http://www.n5ge.com http://www.swotrc.net >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
