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Reviews Categories | Transceivers: HF Amateur (inc. HF+6M+VHF models) | Collins KWM-380 Help


Reviews Summary for Collins KWM-380
Collins KWM-380 Reviews: 15 Average rating: 4.3/5 MSRP: $6500
Description:
Product is not in production.
More info: http://www.collinsradio.org/html/kwm-380.html
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AC5XP Rating: 4/5 Jan 27, 2002 22:24 Send this review to a friend
Good but unworthy to the Collins heritage  Time owned: 6 to 12 months
I had a KWM-380 5 years ago, bought it on rec.radio.swap . My expectations where quite high so when I finally got it it was somewhat of a disappointment, I expected more from Rockwell-Collins. My conclusion is that it is indeed a ham radio, NOT a professional/military grade radio like I originally believed (Yes I know there is an HF-380 as well but it is practically the same radio)
What I did not like: The synthesizer uses two frequency sources instead of one. Very "un-Collins" like. It would have been simple for Collins to design the synthesizer with only one master oscillator, like the 651S-1 receiver had (and the latter is MUCH older, from 1971!)
The synthesizer also is quite phase-noisy, but all radios of those pre-DDS days had that problem.
Also, the variable IF shift does not have a pre-fixed position for USB and LSB. This I really disliked. In fact, Collins should not have given in to this "fashion" IF-shift feature, they should have designed the KWM-380 with one of their superb 500 KHz mechanical filters (or three, one for LSB, one for USB and one for AM like the 651S-1) instead of using a much higher (in frequency) crystal filter which they had to revert to for facilitating this weird and unnecessary IF shift feature.
Also, the pushbuttons on the front-panel were too close together to be comfortable.
What I also disliked was the fact that the circuit cards were not done like plug-in cards on a motherboard. The manual tries to give this a positive spin by stating that this makes service easier. But I feel this to be very un-Collins like (Cost reduction enforced by the new owner in those days, Rockwell?)
What I also disliked is that costs were saved by using those cheap connectors on the internal coax connections. Only for the PA connectors are real SMA connectors used, too bad this is not the case throughout the whole radio.
Also the used ribbon cables are un-Collins; why they used teflon cables throughout most of the radio but then stopped by using cheap ribbon cable we will never know.
The receiver performance was in fact worse than the earlier KWM2(A) radios. I actually considered to design a complete DDS synthesizer for this radio once, that really would have improved receiver performance due to phase-noise reduction. But I figured it would only lower the radio's value so I never did this. Actually, when a good bid came along I sold it again.
There were good points: On the majority it was built well, with high-quality components with the exception of the above cable and connectors.
Last but not least, it holds its value very well especially if it is in mint condition (like mine was)
But I always believed that this radio was unworthy to the Collins heritage, in both concept, over-all construction and performance.
But then, I am a perfectionist. I cannot deny that it is still an impressive radio.

 
KE9OA Rating: 5/5 Jan 9, 2000 10:33 Send this review to a friend
A very good radio, with high potential  Time owned: unknown months
The KWM-380 is a good performer, but there are a couple of improvements that can be made, for those who are brave enough. The first thing one can do is replace the first mixer with a better one. As shipped from the factory, the unit uses a Mini-Circuits SRA-1H mixer. This mixer has a midband SSB conversion loss of around 6.2dB, a 1dB compression point of +10dBm, and a lower cutoff of 500KHz. The MDS of the KWM-380 is .15uV, when using this mixer.
Replacing the first mixer with a Mini-Circuits TAK-3H improves the MDS to .07uV. The TAK-3H has a midband SSB conversion loss or around 4.7dB, a 1dB compression point of +14dBm, and a lower cutoff of 40KHz. It is pin for pin compatable with the SRA-1H, and it is also a Level 17 mixer, which means that it also requires +17dBm, or 50mW of LO drive.
The second modification that one can perform it to bypass the receive high-pass filter. After performing this modification, receiver performance is maintained all the way down to 40KHz.
If you do these mods, make sure you label all of the cables that plug into the main board, since you need to remove the main board in order to do the changes. Also, you need to remove the cover from the first mixer area; this in itself isn't bad, but you do need a good soldering iron with plenty of reserve to remove the shield plate from under the mixer area.
If anybody has any question, feel free to e-mail me at n.gianakopoulos@worldnet.att.net, or pjgianak@collins.rockwell.com, and I can walk you through the particulars.

Pete Gianakopoulos
Cedar Rapids, Iowa
 
W7AX Rating: 5/5 Dec 22, 1999 22:37 Send this review to a friend
KWM380 echo  Time owned: unknown months
I have used several of these KWM380's through the years. I still have one with all the upgrades and keypad entry system and all filters. Of the collection of over 100 radios here, (mostly Collins) it is certainly the most often used and for a lot of reasons, most of which are related in the two preceding posts. Just wish they would make a KWM-2000! Not that I need one. I might just take this one with me when I go away!
 
AD6W Rating: 4/5 Sep 22, 1999 13:08 Send this review to a friend
Simple, stable, reliable, great CW features  Time owned: unknown months
I hesitated to initiate a review of the KWM-380 because it is a collector's item, but after seeing the first post I just had to comment. My 380 was purchased new for $2900 in 1979. It has been on the air daily ever since and has worked many contests, 8BDXCC, Honor Roll, 5BWAS, WAZ, traffic handling, everything you can think of. To say I got my money's worth is an understatement. In 20 years the rig has had 2 failures, at 5 and 13 years. Both times the fault was the 2N2219 in the 24 volt ps inverter. This 50 cent part is easy to replace, so total cost of maintenance has been a buck with 30 minutes of downtime. In 1995 we had a house fire and all my equipment got drenched by the fire hose. I bought the 380 back from the insurance company, cleaned it up, and put it right back on the air. The 380 is very easy to work on if need be and nearly every part is standard. The inside is a work of industrial art. Everything is laid out well and most of the cabling is teflon with gold plated connectors. The final amp heatsink is massive. All boards have enough service loop to be extended while still connected in the radio. Every couple of years I get a hankering to try something new and have bought other transcievers, but they have gone and the 380 soldiers on. It is very stable. Mine has never been aligned since leaving the factory and is still within 10Hz of WWV on all freqs. The stability, look, and feel remind me of the quality test equipment I use at work. The 140Hz and 360Hz CW filters are a delight, and the CW spot button is right next to and below the main tuning knob so I can press the button with my thumb and tune with my fingers to spot a station with one hand! No other rig I know of is laid out like this. Heck, some rigs don't even have a spot function, much less one this well thought out. You get the feeling this rig was designed by someone who actually did some operating. The receiver is a little noisy and mushy when pushed to the limit due to phase noise from its early synthesizer, but cranking in some attenuation solves that. With a good outboard DSP filter to take care of hetrodynes the 380 holds its own with nearly anything I have tried. I just love this rig for the reliability, simplicity and simple human interface. But the real kicker came last year when a friend offered to trade me his brand new ($4000) rig for the old 380. I had to turn him down.
 
KT5X Rating: 3/5 Sep 17, 1999 20:20 Send this review to a friend
standard setter  Time owned: unknown months
This is a Mil-spec radio made by Rockwell when they bought Coolins. Collins required that 3,000 be made for the ham-radio community. It sold for $6,500 which was on third what the same radio sold for to the military. This radio is so stable, less than ten cycles per hour, that it put the old Frequency measuring contest out of business. It has a 140 cycle mechanical filter, and over-rated everything. It benefits from PIN diode modification, and lacks full break-in on CW. Recognize this is a twenty year old radio, yet set side by side with new ones, it may often hear better. It ALWAYS looks better! Just don't try to put it in your suitcase. ;-)
 
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