Can a Collins KWM-2A be set up for 60M? - BoatAnchors Forum at eHam.net

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eHam.net Forum : BoatAnchors : Can a Collins KWM-2A be set up for 60M?

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Can a Collins KWM-2A be set up for 60M?	Reply
by WW0W on November 10, 2004	Mail this to a friend!
Hi, I'm consdiering a KWM-2A for my 3rd boatanchor, but want to be able to operate on 60M. I read that the 2A model can be extended for MARS, in fact, at the Collins Collecotrs site they say "The KWM-2A has an additional crystal board permitting the operator to add 14 crystals to cover frequencies outside the amateur bands. " Could these crystals be chosen for the 60M "channels"? If so, what would be a good source for them and how would you specify each one for each channel? TNX/dave

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by WW0W on November 10, 2004	Mail this to a friend!
I checked in the online KWM-2A manual, extrapolating from their charts, it appears I would want something equivalent to Collins PNs 290-9018-00 and 290-9019-00, which should give the rig coverage from 5.2MHz to 5.4, and 5.4MHz to 5.6 respectively. This is a wild guess, can anyone confirm that this wold work?

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by AE6RV on November 10, 2004	Mail this to a friend!
The frequencies between 5.0 and 6.5 Mhz present a problem for the KWM-2/2A and S-Line gear. But, according to http://www.collinsradio.com/SIL2-75.pdf, 5.3 to 5.5 is available. You would need to get a 8.455 crystal and put it in an "A" slot, I believe. Or you could split as the other poster suggested. All the major crystal manufacturers know how to make Collins crystals. I do have a KWM-2A, and it has an extra crystal deck on top of the chassis, which makes it convenient to add the WARC bands. Be sure to check out collinsradio.com. Bob

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by K5MYJ on November 22, 2004	Mail this to a friend!
I thought 60M was a low power band? Like 50W PEP! <<In a nutshell, FCC Rule §97.303(s) states that General class and higher licensees may transmit only upper sideband phone on the channels, and the transmission can occupy no more than 2.8 kHz, centered on each of the frequencies. Maximum power allowed is 50 W PEP of effective radiated power, with a half-wave dipole antenna presumed to have no gain. As secondary users of the channels, hams can't cause harmful interference to primary users, such as the US Coast Guard or other government users. >> Bob Macklin K5MYJ/7 Seattle, Wa. "REAL RADIOS GLOW IN THE DARK"

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by AE6RV on November 22, 2004	Mail this to a friend!
"I thought 60M was a low power band? Like 50W PEP!" It is, but the KWM-2A is easy to limit to 50W by simply backing off the loading control. Actually, though, it's 50W compared to a dipole on 60m. So, if you're gonna use a beam with 10db gain over a dipole, you'll need to limit yourself to 5W output from your transmitter. Bob

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by AE6RV on November 23, 2004	Mail this to a friend!
I have a couple of WARC crystals coming in a week or 3 for my KWM-2A. I'll post here when I get them.

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by WD4HXG on November 25, 2004	Mail this to a friend!
The Collins Specifications in Section 5.3 of the KWM-2A manual indicates the rig is limited to operation from 3.5 - 5.0 MHz and 6.5 - 30 MHz. Refer to Section 2.5.1 Selection of Crystal "CAUTION" notice (page 2-8) in the manual. I have heard a few ops comment that it is not a problem to rock the rig for operation on 60 Meters but unless a properly certified radio tech or engineer verified that the spurious products, frequency stability, and spectrum bandwidth utilization met FCC specs my rig would not have the rocks for 60 meters.

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by AE6RV on November 25, 2004	Mail this to a friend!
The Collins Service Information Letter - SIL2-75 has clarified the S-Line and KWM-2/2A operation in the 5-6.5Mhz frequency range. From that document: (quote) "The region between 5.0 and 6.5 MHz has always been defined as unsuitable for operation with the S_Line and KWM-2A equipments due to spurious signals inherent in the equipment. Many requirements for operation in that frequency segment have caused a complete study and resulted in the following list of acceptable operations in that range." <The complete list is given but I'm not going to repeat it here. However, the complete range of 5.3-5.5 is listed as usable. Note the following.> (quote) "The frequency bands of non operation are: 5.970 to 6.0 MHz 6.035 to 6.165 MHz 6.2 to 6.230 MHz" All other frequencies in this range are acceptable for operation. The SIL2-75 document may be viewed in its entirety at: http://www.collinsradio.com/SIL2-75.pdf I hope this puts to rest the doubts concerning 60 meter operation with this equipment. Bob

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by W7DJM on November 26, 2004	Mail this to a friend!
I don't understand, unless you use an outboard digital freq display or freq counter, how you would keep it on frequency? This is the one band where you have to be "on channel" as opposed to all other bands.

RE: Can a Collins KWM-2A be set up for 60M?	Reply
by AE6RV on November 26, 2004	Mail this to a friend!
"This is the one band where you have to be "on channel" as opposed to all other bands." I guess I don't appreciate the problem. The readout has a precision, if not necessarily accuracy, of 1KHz. The accuracy isn't generally off by more than 200Hz or so. There is about 1/8" between each KHz marker, giving me the ability to make a very good guess as to where I am within that 200Hz error factor. The allowable bandwidth on 60M is 2.8KHz, whereas the bandwidth of the output of a KWM-2A is around 2.1KHz. that leaves 700Hz to play with, or about 350Hz guard on each side. I'd say it wouldn't be that hard to stay on frequency. These things don't drift that much after 15 minutes of warmup. As an aside, I have noticed someone on 75 meters who says he's transmitting on 3.8777. According to my dial, he's on about 3.882. That's a long way off. It makes me wonder if he's ever bothered to check his frequency against WWV. Fancy digital readouts can be deceiving. The most I've seen this dial off so far against know accurate sources is a couple hundred Hz. But, I suppose there MIGHT be a glitch at that point of the dial. It's not too likely, though. OTOH, I wouldn't even consider putting my Atlas 210X on 60, even though I could probably retune it there. Precision and accuracy aren't necessary correlated. Bob

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