N9EWO Review :
KENWOOD / Trio  R-1000
LW / MW / SW Communications Receiver

Kenwood R-1000 Communications Receiver .
Manufactured in Japan from 1979 to early~mid 1986.
Also was sold as the Trio R-1000 in some parts of the world.
In our view it's the best "Communications Receiver" Kenwood ever made.

  Many used samples around are lacking the locking handle which works well as a tilt bale. Cabinet paint scratches / chips extremely easy and the main receiver PC board came in at least 2 versions. Only Kenwood HF receiver that included 3 "stock" bandwidth filters. SSB (narrow) filter is a 11 element "metal case" Murata CFJ455K5 (2.7 Khz) . The W-I-D-E 12~15 kHz filter allows for excellent audio quality when conditions warrant , and also the WIDE filter selection adds a bass enhancement circuit to the audio amplifier (except very early samples) . The set's excellent non hissy - non distorted audio , good AGC (all modes, see text) , super wide IF filter capability and large internal speaker, all give for the best audio of ANY other set Kenwood receiver EVER made (in our testing and view). No microprocessors and only uses a PLL synthesizer. While fairly stable after a 1 hour warm up , manual ECSS is only OK (poor when cold). One can cheat the sets mode buttons to allow use of the wider bandwidth filters use in SSB modes (even allowing DRM reception without any converter when connected to a computer with the DREAM software). Uses no plastic gears or dial strings in the tuning system . (N9EWO photo)

Country of Origin  : Japan
Approximate "Test Samples" Serial Numbers
(3 samples tested for this review)
1st Sample : (owned mid 1980 , number was not archived)
2nd Sample (Made in Dec 1981): 112017x
3rd Sample (Made in Dec 1981) : 112017x

We have used / owned the Kenwood R-600 , R-2000 and Yaesu FRG-7700 models for reference in this report. 


N9EWO's Review on the Kenwood / Trio  R-1000

Radical Receiver Model for Kenwood in 1979 / Other Competing Models at the Time in the Same Price Point  - "No Match"

Prior to the R-1000 (which was known as Trio / Kenwood at the time), previous "solid state" HF receiver models were the QR-666 and R-300 , both more simple analog designs (not tested and being older designs are ruled out as being worthy in any comparisons here) . Were also sold under the "Trio" name for some markets . In North America were always sold under the Kenwood label. Frequency coverage in the specifications is listed from 200 kHz to 30 MHz. However the sensitivity is pretty dismal (as stock) for Long Wave and Medium Wave uses (more later on this).

The R-1000 was released on the US market in 1979.  It was the first communications receiver (at a reasonable price point) to feature a "locking" Mhz band selector and getting away from tedious preselector and Mhz band tuning which Yaesu and other "Wadley Loop" designed models used at the time (examples : Drake SSR-1, Yaesu FRG-7 and FRG-7000.). The R-1000's design uses PLL circuitry and was already common with JRC receivers of the day before the R-1000 (NRD-505 and 515), but at a much higher price.

Yaesu released the FRG-7700 in 1981 to compete , but is no equal to our ears. Uses the same tuning scheme and basic design and offers similar 3 IF bandwidhs (including a nice W-I-D-E one), but the outcome was not the same in our tests. We detected the FRG-7700's audio loaded with IF hiss and is less dynamic sounding. Yaesu did offer a 12 channel memory unit option for the FRG-7700 which was rare for 1981 , but of course this type of add on can only increase the digital noise/hiss and decrease audio quality even further . But with even without the option installed the audio was no where near as good as the R-1000's.

IF Filters / Early Versions / AGC / Superb Audio Overall

"Out of the Box" R-1000 IF Filter selections (all muRata Ceramic type)
AM WIDE : CFW455F (6 element plastic case , 12 Khz)
AM NARROW : CFW455HT (6 element plastic case , 6 Khz)
SSB : 11 element "metal case" CFJ455K5 (2.7 khz)

In all but very early samples , Kenwood featured a IF "Filter Select" 3 pin plug on the top RF-IF board (located near the 3 IF filters , see photo below). This allowed the owner to choose between using the 6 and 12 Khz filter in AM mode (as it comes stock, and how we like it) or using the 6 Khz filter in WIDE and the 2.7 Khz SSB filter for the AM narrow selection (which we would never do).

Also in all but the very early samples, when in AM Wide IF filter selection , there is a bass boost circuit that is engaged on the audio amplifier. Mind you this boost will not knock you out of the room, but is most noticeable and useful.  No hiss,  not muffled "woolly" , not excessively bassy or overly sharp audio. SSB is near perfect as well. Of course we have proper separate USB and LSB oscillators and is extremely clean and stable. Only one note is with certain speakers (epically ones that have a tweeter) one might hear a touch of SSB clipping distortion on certain signals. But this is being very picky and most will not notice it.

With very early samples there will be no filter plug and no 2 sockets as shown below for the filter change. However there was a modification kit (BWK-1) that accomplished this but with no easy way switch back over. Also early samples had a extremely SLOW AGC decay rate . Our first 1980 sample had this SLOW AGC capacitor and was awful. It too can be modified and improved like later samples (capacitor change) but might require removal of the RF / IF PC board and that is NOT a easy task (with some samples this capacitor is on the rear of the mode switch). Even with the 2 late 1981 test samples with the updated AGC capacitor , the decay rate is still a bit on the slow side, however we find this to be an advantage and not a drawback. We very much love the R-1000's slower lone AGC.

Here is a PDF (Kenwood Service Bulletin) that covers both topics with much more information on this.

Also in all but the very early samples, when in AM Wide IF filter selection only , there is a bass boost circuit that is engaged in the audio amplifier circuit. Mind you this scant boost will not knock you out of the room, but is most noticeable and useful. Depending on the speaker used, one may not here any difference at all here.

The "three" STOCK R-1000's Ceramic IF Bandwidth Filters (left side of photo above).  The R-600 and R-2000 models only included 2 filters and lacked the very desirable 12 kHz CFW455F WIDE filter for fantastic audio when conditions warrant. Both other models used a lesser performing (and cheaper) 6 element SSB filter . But the R-1000's above average audio quality is also because of other factors in the design. The R-600 and R-2000 had much inferior audio quality to our ears (as did the Yaesu FRG-7700) . Lacking electronic switching (say for mode and bandwidth) certainly are pluses to help keep general circuit noises down. The R-2000 in our testing was awash with junk from it's very noisy microprocessor and contributing to the generally raspy , hissy and tiring audio quality. (N9EWO Photo)

Sensitivity / Dirty switches / MW Attenuation

Sensitivity is right up there when I even compare side by side with the best receivers of today. However with any used sample, one MUST CAREFULLY clean 5 switches with a good quality electronic switch cleaner such as Deoxit D5S-6 (only use D100 on dirty variable controls) and once in awhile do general maintenance on these 5 switches to keep full sensitivity (and this is not that often if kept in at least intermittent use) . Be sure and properly clean up the over spray after.

*** These 5 Switches are ***
- MHZ Band Switch : Not so easy to force the spray into this switch however (will take some work to inject spray into it's cracks).
- ATTENUATOR Switch : Located in the right top of the RF / IF board near the rear (follow the long shaft).  If heavily dirty this may take some additional soaking time and multiable treatments as I had to do with one of the our used samples (it was stubborn as it sat for years, before we cleaned this switch one test sample was not receiving anything).
- SW ANT SELECT Switch : Located on the bottom section (rear) near the SO-239 antenna connector. Can get as dirty as the ATTENUATOR switch.
- FUNCTION Switch : (Long switch Top left side front) : Not as problematic as the 3 above.        
- MODE Switches: Actually this is a bank of them. More that are not so easy to get cleaner into. But are not always problem switches.

The R-1000 uses a dual up conversion super heterodyne design, with balanced MOSFET circuits being used in BOTH mixer stages. One may start to compare to the lower cost R-600 which came out in 1982 touting TRIPLE conversion. But the R-600 sold for less dollars and it showed. Hissy and fewer bandwidth selections (with a low cost SSB filter and NO desirable super wide filter offered). Also the main tuning capacitor was of lower quality along with inferior gearing as well as being a much less stable design (so excessively drifty). The R-2000 model while sporting full microprocessor operation, was awash with hash and hiss for not so great audio. They also suffered from the same lousy included IF filters and just a plain disappointment to our ears (including the cheaper plastic SSB filter).

As with many Kenwood and Icom receivers, the R-1000's Medium Wave input circuit (0 and 1 on the BAND selector, so up to 2 Mhz) includes an Attenuator to reduce overloading. This consists of 3 resistors in the case of the R-1000. It is NOT selectable and always active. There is a modification around the internet to remove this attenuator (subscribe to the R-1000 Yahoo Group for this information...see the provided link at the bottom of this page) , but depending where you live this might it not be a good idea. We have NOT tested this modification and can't say one way or the other how well (or not) it works. As stock MW sensitivity is poor. NOTE : It has been said elsewhere that the reason for the MW attenuator to help keep MW signals from ghosting into the SW spectrum. With our unmodified stock samples, he have yet to hear any local MW station intrusion.

         The R-1000's Top RF / IF PC Board. Internal speaker can be unplugged from PC Board (2 pins) The white plastic coupling piece that attaches the long ATTENUATOR shaft can become loose in time. Be careful over tightening it's hex set screws as it can crack very easy and replacements are hard to come by. Same goes for the MHZ BAND knob. The main tuning knob is a push on affair. (N9EWO Photo)

WARNING : I will NOT be held responsible for any information that is listed here.

Power Supply Bug-A-Boo's / Loose Antenna Connector Common / Quite Stable After Warm Up

As with many Kenwood HF receivers, the internal power supply runs on the HOT side. It's not so much the very nice shielded power transformer where the majority of the heat comes from. It's the components on the power supplies PC board "heatsink" that gets near too hot to touch after some time in operation. We have never seen any failures of any the components on this PC Board, however in time the connections in general can become very flaky to non existent. One very common complaint is the receivers frequency counter goes floating all over the place or a fixed 39.545 Mhz display . Also the receiver may experience excessive drift. This is usually because the 5 volt output has failed or near failed on the Power Supply board. Most times this can be totally fixed by just re-soldering all connections on the Power Supply board. Will need to remove the mounting screws on the this Board and at least remove the long white plug. Flip it over and using good old fashioned LEAD type solder (avoid the Lead Free stuff), reflow the connections. Notorious bad connections are on that long connector socket pins closest to the heatsinks (dual 5v + connections). But just re-solder the entire board.

See our PDF Document here for more information

Not saying this might be the only problem that can crop up, but is the most common one. Some have reported the main power supply capacitor has failed, but I have yet to see this with any of my test samples and friends R-1000's.

Loose SO-239 connectors are common on all Kenwood receivers and transceivers that use (what I call) the strange single "wavy mounting nut" . Not so easy to tighten. Just about every used R-600 / R-1000 / R-2000 I have encountered has had a loose SO-239 antenna connector . See photo below for a picture of this.

The R-1000 is quite stable after a warm up period. I would say near an hour for really decent stability. Mind you (manual) ECSS reception which is possible even being very touchy to tune in, still tends to be a little drifty for that use (but still usable). Remember the design is microprocessor free .

Inconsistent Florescent Display Quality

One little quirk that I have observed with the Kenwood R-1000 since day one on various samples , is the brightness / quality of the FUTABA 5-BT-05 florescent display used varies greatly from sample to sample. That is some segments of a digit can be severely diminished , or one side of the display can be brighter than the other.  This quazi defect is more noticed with the "Dimmer" on. Not to say this issue have not inflicted other sets over the years that use florescent displays (it sure has), just that Kenwood did not have much of a rejection curve for semi sour looking displays in production. Some samples look perfect in this regard , while others are not so hot. 

The R-1000's Bottom PLL Synthesizer and Power Supply PC Boards. There are NO microprocessors in this HF receiver. NOTE : The "Service Manual" calls the Power Supply PC Board as part of the PLL Unit. (N9EWO Photo)

Dynamic Range / Image Rejection / Spurious Signals / Noise Blanker

Dynamic range (freedom from overloading) is adequate . Not to say that it cannot happen with powerhouse short wave signals say on 49 meters at night connected to a good outdoor antenna. The first click (20 db) of it's RF Attenuator does the trick to squash this. But not too often that is required (at least with our antenna's). Even by todays standards it's not bad at all. However I do remember our first 1980 sample having more overloading issues ?? So perhaps changes were made with later samples ??

Image rejection is equally decent. No ghost signals appear 910 khz away. However there are strange SW spurious signals that do crop up when signals are the strongest . Signals from VERY STRONG lower frequencies (say at 6 and 7 Mhz) pop up in the 14 and 15 Mhz area. Never grasped what is going on here, but I would not call it overloading . But again the RF Attenuator fixes this and is another one that only rears it's ugly head once in awhile. Perhaps this has something to do with it's limited front end filtering (which it does have) ??

Noise blanker is by late 1970's standards. Not adjustable and it's either on or off. It can be useful for some power line or other electric buzzes. But it will need to be on the stronger side to have any effect. Sometimes it helps, other times it does not.

Cheat The Mode Buttons / DRM Possible Without Mods

You say you wish you could use the AM "NAR" and "WIDE" in SSB modes ? Being the MODE buttons are of a mechanical type, that's no problem . Just push either of the SSB buttons in along with the AM Mode "NAR" or "WIDE" at the same time and that's it. It is a bit tricky to get both buttons to lock into place , but it works. Also comes in handy when I doing ECSS reception. But due to the not so perfect stability, it's of only minor use here .

When SSB is used with the "WIDE" (12 and NOT 6 kHz) AM Filter and plugged into a computer running the DREAM software, we were actually able to get DRM broadcast to decode after some fine tuning. This is without any modifications or other add ons to the receiver. But proper audio connections are required to have any chance for this to work (see the Record Output Jack connections below).

A Real Frequency Counter  /  SSB Readings Will Be Off

The R-1000 uses a real frequency counter LSI  IC (oki MSM5524) . Our first 1980 sample (which was a early manufactured one purchased brand new) suffered from inaccurate counter readings. It was dead on at one end of a MHz band and by the time we tuned to the other end it was a good 5 Khz off (AM Mode). This turned out to be a misalignment at the factory (sample was made during the shake down cruise I guess). Our two current , Dec 1981 samples are dead on anywhere I tune them.

When tuning SSB modes the counter will be off. This is not a fault and totally normal as the counter is only accurate with AM carrier signals (it's in the design). So for a little math and this may vary slightly depending on any given sample. But you get the idea.... :

R-1000 Display Offset When Tuning SSB
USB : Subtract 1 kHz from what the display indicates
LSB : Add 2 kHz from what the display indicates

Record Output Jack - Is at Mic Level (Not Line)

The RECORD jack is mounted on the FRONT of the receiver (1/8 inch mono phone jack) next to the 1/4 phone headphone jack. Is slightly recessed. Has a very clean unbuffered output and is at a low MIC level. That means that it needs to be connected to a MIC input of any recording device or computer (a standard line level connection is too low and will not work). We need all a line level for our audio switching system, so we added a ROLLS MP13 Mini-Mic preamp and this worked perfectly after adjusting the gain with it's level control to match our requirements (this will also work for the Sony ICF2010 / 2001D and other OLDER Sony SW sets as well ).  NOTE : The Bass Boost circuit in the WIDE bandwidth is not seen at the "Record" output .

R-1000's rear panel. The "DCK-1 13.8V DC Input Jack / Cable Kit" was optional and now very rare on the used market.
The 3 spring clips on the far left (MW-GND-SW B) are notorious for not pushing in and breaking.
Best HF Receiver Kenwood Made in Our View  / They Have Held Up Well Over The Years (Properly Treated)

Please Note: We have NOT used the R-5000 model in our testing over the years, but with it's lack of the the WIDE 12 Khz filter , issues with the PLL Potting compound that goes sour (that is almost guaranteed to happen sooner of later and will make the set inoperable). Plus the front panel keys that usually go AWOL. We strongly feel that the R-1000 is the best HF receiver that Kenwood ever produced. It has held up better too with age and not one dial string to break . 

True, it lacks the fancies of a RF Gain control, Pass Band Tuning, Sync Detection,  Notch Filters , Memories (which were very rare in 1979)...etc etc . But the simplicity is another part of the set that made it very special yet still provide performance with excellent audio quality.

As it goes with any vintage receiver, the used market is awash with good samples and also ones that look like they have been through a few dozen wars. There are normally used R-1000's that pop up on the market once in awhile as it was in production for over 6 years. 

Dave N9EWO

c N9EWO, all rights reserved
ver 1.6

LINKS (All Subject To Change Without Notice)

Kenwood R-1000 Yahoo Group

DXing.com R-1000 / R-2000 Page

eham R-1000 User Reviews

R-1000 Service Bulletin , Slow AGC and Filter Switch for very early samples (PDF)

R-1000 Service Manual

R-1000 39.545 Mhz Display Repair (PDF)

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