KW Electronics Ltd - A very British Company
Early in 2016 the nostalgia bug bit again after talking to quite a few chums who had connections with KW Electronics (Dartford UK) or who owned the kit. This Company had a special place in my teenage Ham years as my good friend Paul G4BXT (now sadly SK) lived near the works. On some Saturdays the two teenage hams would go into the showroom to play with the shiny new KW2000B's, KW Atlantas and the separates. I found out later that two friends I met in 80's worked for the Company before it folded in the 70's
KW started life in January 1956, when Roland (Rowley) Shears - G8KW and Ken Ellis -G5KW, began importing Geloso VFO's from Italy and making antennas, dummy loads and accessories for the UK ham market in Rowley's house. This rare ID Plate shows Rowley's house address, its on a TVI filter to notch out UK VHF TV CH1 on 45MHz. Part of my collection and it dates from the late 50's
AM transmitters and receivers quickly followed with the KW Valiant, KW Vanguard - and cute little KW160. SSB equipment appeared in the late 50s but in the 'boat anchor' style - the early Mk1 KW Viceroy SSB transmitter had a huge separate PSU.
KW even managed to get one of their AM Transmitters into a James Bond film - Dr No - all British line up, KW and Eddystone !
The KW 'G LINE'
Early in the 60's Rowley and his small team must have realised that smaller (and lighter) SSB equipment was going to be the future of the hobby on HF. In the US the Collins Radio Company had started the trend with their innovative SSB transceiver - the KWM-1, shortly followed by the legendary KWM -2 - a masterpiece of radio design. The KW team took the basic concept of the Collins equipment and re-designed it so it could be manufactured in the UK and sold far cheaper than any imported US equipment - the team called it 'Project 2000' . This rare picture of the prototype looks really nice and things became a bit more cluttered with the addition of VOX and a IRT in the final radio.
Corners had to be cut however - the Collins permeability tuned VFO (PTO) and pre-selector were abandoned in favour of conventional tuned circuits with variable capacitors - The front end tuned circuits on the higher bands were wound directly around the ferrite slugs and placed in series (makes alignment a bit more tricky!) and construction was simplified. It may be unkind, but compared to the superbly engineered and documented Collins KWM 2/2A the KW2000 was clearly more of an 'amateur radio' product.
The basic radio architecture is the same - 455kHz IF, Kokusai Mechanical filter (instead of Collins), 200kHz band segments, 6146 output tubes, KW also added 160m, IRT and the very nice turned aluminium knobs added a lovely touch. Thus the very British KW2000 series of HF radio transceivers were born. The earliest model released in 1963 had one 6146 and was crammed onto a chassis that was little too small, it also drifted if used mobile as the vehicle battery voltage and the VFO heater supply changed - pull away from the lights and move up the band!. But it was far cheaper then the competition and sold well, although clearly some improvements were needed. They first came in the form of the KW2000A model from around 1966, two 6146 tubes were fitted and the VFO and premix valve heaters were run from a separate 6V supply to cut down the drift when used mobile, the case was made a bit bigger and KW called it the 'G line'...hmmm Collins influence again
On the left is one of the early KW2000 models (although there were some changes as KW fiddled with the design - very early ones were not in a 'G Line' case). On the right is the authors KW2000A. The dial only has a readout to 2kHz, and has a tendency to wear so that you set a frequency and then the dial moves a little..called 'KW lumpy VFO syndrome'. There aren't enough 200kHz segments to cover 15m and 10m - another compromise
By 1969 the storm clouds were gathering for UK and US Ham Radio manufacturers, but KW managed to upgrade the 2000A to the 2000B and found a real winner in the UK market, The big improvement was a 2 speed dial mechanism with better readout and the rig sold like hot cakes for a few years. The last gasp for the 2000 was the 2000E from 1973 until around 1976 (its missing from the 1977 KW catalogue). Although it had an improved receiver front end and 500kHz band segments, it suffered from further cost cutting, strong competition and limited development - and there was no denying that by the time of is introduction all valve HF SSB transceivers were a dying breed (it turned out to be a slow and painful death for Drake, KW and Swan amongst others). The commercial variant - the KW2000CAT - channelised radio telephone sold well into the 70's and in its last incarnation used solid state Plessey devices for the low level signal generation.
KW tried to break into the US ham market in 1969 with the KW Atlanta (more on that further down this page). The Company was sold to Decca in 1974 (Decca were more interested in the profitable commercial arm of KW than developing the ham radio line), but by then sales of Yaesu, Icom and Kenwood had grown rapidly in the UK, and - shock horror! - they used extensive solid state circuitry. The Yaesu FT101 was the epitome of Japanese design and innovation - it was the next generation. The last catalogue of KW ham equipment is from 1977, Decca then ran into financial difficulties and were absorbed into the Racal Group in 1980. Rowley bought the rights to the KW name back along with quite a lot of assets and carried on trading as a ham radio supplier selling KW ancillaries and TEN TEC rigs until he retired in 1989.
Peter Chadwick G3RZP worked for KW for a few years and wrote an excellent article in 2010 on the KW2000 series, I have linked it here. The inspirational founder of KW - Rowley Shears died in 2009 - and only after his death did his amazing wartime radio exploits come to light - but that is another story!. There is also an avid group of KW collectors and restorers on the KW Yahoo Group. Every January a group of KW enthusiasts get together on the HF bands and celebrate the founding of the Company in 1956..look out for us as GB8KW, GB2KW and even G8KW now issued to to Rowley's son Richard
KEEPING THEM GOING
I have had no real problems in getting any KW gear back on the air - the simplicity of the design means that there is little to go wrong. This valve gear is best looked after by those who really know what they are doing, you need to get inside and be aware of the danger of high voltages. I have seen some really daft questions on the forums like - ' my Drake TR4 has stopped transmitting..any ideas?' . All the valves used in KW kit are available, passive components are easy to replace and even the mechanical IF filters can be replaced with more modern Murata CFJ455K variants (although these are also getting harder to get). Resistors go high and are easy to check, Hunts caps are awful (but not in every KW), the resistor trimpots used in the RIT and S meter circuitry get dirty and cause problems (erratic S meter, different TX and RX frequencies) and I change them. Relays can be problematic, clean the plug in pins with metal polish and the contacts with non abrasive cleaner. Disc Ceramic caps are pretty reliable. I have built up a stock of parts that should last me out.
G3ZPS LATEST - FEBRUARY 2017 - KW2000E
Never expected to find a rare super clean KW2000E, but I did. At one of my radio clubs a local ham heard me talking about KW equipment..he offered me his KW2000E at no cost as he was preparing to move house..would not take a cent for it..so I made a charity donation for my conscience. I got lucky yet again with a radio that had hardly any marks and had been properly stored for over 20 years. Came complete with PSU and manuals. One day of cleaning pots, switches, valve holders and 'soft start' power up saw it come to life without a hitch.
Initial under chassis inspection revealed a new RS O/P transformer and some obvious resistor changes where the mechanical filter connects to the first RX IF amp (6BA6). I am reluctant to put all the values back to stock in case there are other mods that I have not noticed. The VFO stability is better than my KW2000B (the E takes less time to settle down). Uses a couple of rare tubes that I did not have in stock - 12BZ6 RF amplifier, and ECC85 first RX mixer.
Its a strange radio with a mixture of improvements, poor design choices and cost cutting over the earlier 'B' model - much better front end on RX, 500kHz band sections but the proper tube S meter amplifier of the A and B was left out (although a spare relay cutout can be used to put it back in ). The rear octal connector for an external VFO (as on the 2000B) is also missing and blanked off. As the E has 500kHz band segments KW could no longer use the broadband first IF of earlier models and had to tune this IF in parallel with the VFO. This meant adding extra gangs to the VFO capacitor which would no longer fit inside the existing box..so the capacitor sticks out the back of the now open VFO in what looks like a horrible bodge. KW had the same issue with the KW202 receiver.
KW never got to grips with a decent 1kHz dial readout either, the 2000E was a step back from the 2000B, and was only graduated every 5kHz. This is a legacy of using a Jackson slow motion drive, Drake and Yaesu sorted this years before by using a bespoke assembly for their VFOs. Quite why KW bothered with a WWV band position is also beyond me..it has a 100kHz calibrator, and with 5kHz readout - its a pointless addition. I have also noticed some spurious signals on receive that are hard to pin down..odd as the mixing scheme is the same as other KWs and they don't have them.
The 'RF Gain' control is another odd part of the design. KW had a lot of overload problems (probably on 40m) on their earlier rigs and to get round it just stuck a 5K pot across the antenna where it goes into the receiver..so not a gain control at all, just a crude variable front end attenuator (the KW202 Receiver has one). Unlike the AGC gain control of the A and B models, on the 2000E there is no way to manually adjust the RF and IF gain of the receiver at all...although I understand things may have got so bad that KW offered a 'kit' to replace the RF gain control of the 2000B with this front end attenuator. Its a real pity that KW couldn't deliver with the E, it was probably conceived as a stop gap until the doomed KW2000D was developed (only prototypes made)... but unfortunately it was too little and too late and signaled the end of all development on KW ham radio gear.
I had trouble with the main switching 12V 4 Pole Relay on this rig..didn't take long to spot part of the problem..when I removed the cover to clean the contacts the base of the relay had cracked so much it literally fell apart !. The culprit appears to be excessive heat as the relay is close to two very hot parts of the radio..the audio output valve on one side and a large wirewound resistor on the other. It was almost too hot to remove with bare fingers. I had a spare but have since located a supplier of modern plug in replacements from UK supplier RAPID
Plenty of contacts on 40 and 80 but may need alignment on 20 / 15 / 10m
OCTOBER 2016 - KW 2000B
It took me many months to find a really clean KW 2000B, but one turned up on eBay in October 2016 just a few miles away. The key for me was that the front panel was unmarked and it looked like it had been owned by a lab. It had BT (UK telephone) stickers on it and had not been bodged, abused or dented..in fact very few marks. It was bought at an auction a few months before as it looked nice, but its owner couldn't get a sound out of it and asked his mate to sell it. The PSU was also very clean and he said the radio lit up. The main cosmetic damage was to the radio bezel which had been covered with sticky tape to protect it - although it still had some marks. Year unknown...sometime between 1969 and 1973
Once home it was obvious in minutes why the radio made no sound when he plugged it in..The headphone socket had failed internally and left the loudspeaker permanently disconnected...fixed that it came back to life on RX. All relays came out for cleaning of both the sockets and the actual contacts, bandswitch was cleaned and we held our breath for TX..again no problem and contacts made straight away. VFO drift is quite bad on this radio even after an hour warmup and I have bought a Cumbria Designs X lock 'Huff n Puff' VFO stabiliser to make this 2000B usable without constant tweaking of the VFO. This is an easy fit as the 'Cal' control can be used to feed the correction voltage into the VFO.
The X Lock is now fitted to the KW2000B and has stopped the drift in its tracks. The X Lock needs to voltage control the VFO and there are a number of ways this can be achieved. In the 2000B I decided to use one that was already fitted inside the VFO - the one that allows the VFO to be moved a few kHz to get the dial calibration correct. My initial implementation meant the disconnection of the calibrate input to the VFO (purple wire), disconnect this wire and connect the X Lock directly to this pin - re-adjust the VFO coil to bring the 100kHz calibrator back to the nearest 100kHz point. There is a slightly better option which I may move to that would allow the CAL control to have small effect, this sums the 2 DC voltages together with a couple of opamps. I have been careful to ensure the mod can be reversed without any changes to the radio..should a purist own it in the future. I powered the board from the 12V AC heaters with a single diode and cap to get 14V DC. Look at my video here - Steve's X Lock.
Some FM on the VFO on speech peaks caused the X Lock to drop out on TX. Dale W4OP fitted an X Lock to a 2000B a few years ago and mailed me a couple of mods he carried out. A solid state stabiliser for the 150V to the VFO (using the amazing LR8N3 chip and a TIP50) and simple FET buffer on the VFO output. The FET Buffer cured the FM, but I put the 150V regulator in as well.
The dreaded Kokusai 455KHz mechanical filter is pretty good, but as with my other KW gear the filter 'drifts' towards the LSB carrier crystal making USB a bit thin sounding. I have some ceramic resonators which make good carrier oscillators than can be moved slightly to solve this issue...The filter drifts because the mechanical element gets clogged with the deteriorating packing foam inside the can (over a period of 45 years it turns to a brown goo!). Cleaning the internal element of these filters is difficult (but not impossible) and normally brings them back to the correct frequency. All in all this radio appears in very good order.
CABINET / BEZEL RE -PAINT
Re-painting can be very daunting, but I enjoy it. For Drake and Heathkit I always use Hammerite - Drake is black and Heathkit is dark green. I am not too much of a purest for the exact colour - you'll never get a perfect match. All my Drakes look as new in satin black, and my little Heathkit looks great in satin dark green. Scratched cases and damaged bezels look dreadful and are easy to bring back to life, only a few days work...come on guys tatty radios look...tatty, give them a proper new life !
KW gear is a little harder as the cabinet and bezel are different colours (like Collins) - the main case colour is close to Ford Polar Grey, the bezel is lighter and Rover Tempest Grey is close. I rub down with a light emery paper block soaked in water...and then use 2 coats of car (automobile) paint primer and then 2 coats of the top colour..always looks fantastic...here is the KW bezel primed and right finished on the rig..far better.
On both my 2000A and 2000B I have inserted an inline phono plug and socket in the speaker lead to the PSU. This allows the use of other speakers with the radio, or in the case of my 2000B cured a ground loop hum by plugging the speaker into the headphone socket rather than going through the rear multiway plug - strange but true!
KW 2000A AND KW VESPA MK1
Ebay purchase delivered in Jan 2016 and I was more excited than a kid at Christmas. Opening the boxes revealed a near mint KW2000A with hardly any marks to show its age and the same with the Vespa, The 2000 had been well looked after and had been the subject of a part restoration. I sat stunned in front of them on the kitchen table. Now the hard part. The KW2000A PSU looked correct but did not appear to match the transceiver - on power up all the voltages checked out, but the radio just gently hissed. On close inspection two tubes appeared to have no heaters, the VFO and Premix..how could this be?, surely all the heaters were wired together. Emails to KW collector and guru Guy G0UKN followed..he told me those two tubes have a separate heater supply...what??. I had been fault finding with an early Schematic for the KW2000 (not the A,B or E) and this didn't show it. Then the penny started to drop - the Power Supply was for the earlier version of the radio and it didn't have the separate heater supply for the VFO. I traced the wiring and sure enough that was the problem, KW used a 9R dropper resistor in the PSU to get the 12V down to 6v for these two valves. A rummage in the junk box and the radio woke up!
Why the earlier restorer (who had done so much to the radio) missed this, I will never know. Perhaps he too was working from the wrong schematic and just couldn't work it out. Any how back to life and good power out on 40m, 80m amazing !!
Next I turned my attention to the KW Vespa Transmitter and its obviously re-built power supply, oh dear, what a mess. No way was I turning it on in this state - even more dangerous than when it came out of the factory in its odd cardboard cover, re build required. I changed caps, fixed awful dry joints, corroded fuse holders and put decent HV diodes in for the 750v HT..the ones in there did not look all that great.
After a 2 day total rebuild and test, the PSU was in good working order. Firing up the radio was met with ZERO output..not a milliwatt. Out with the scope and it soon became clear that the dreaded 455KHz Kokusai mechanical filter was as dead as a dodo, 455KHz carrier went in and nothing came out on the scope As a quick and dirty check I bypassed the filter with 1000pf...Bingo !!! Double Sideband and loads of drive. In the box of bits that came with my purchase there was 2 other filters one opened and one sealed..On a whim I put the sealed one in the VESPA and it came to life again...super reports on 40m with a Shure 444. Later I found some resistors had gone high, and the curse of the KW Owners manual caught me out several times. Its one area where they really cut corners - the manuals are awful, child like drawings, schematics and charts with errors. Compare them to Swan, Drake and Collins and you will see what I mean.
Next purchase a very clean KW201 Receiver from the 2016 Canvey Rally (Essex UK). Cheaper than eBay and promised as working on AM and with a good Mechanical Filter - but not good on SSB. This was a quick fault find quickly traced to an almost shorted coupling cap from the anode of the product detector to the grid of the Audio O/P valve. That's why it worked on AM but not SSB. This receiver has a 3KHz filter which is too narrow for AM but means that SSB sounds great provided there are no adjacent stations - of course you can add the optional Q Multiplier - but I have never seen one for sale BEWARE the old carbon composition resistors in these KW gear, in the KW201 2 failed within a few days of getting it going, they all go high, but some just go VERY high.. Although the 201 came out at the same time as the VESPA transmitter they cannot 'transceive' together and have to be manually netted together - this an another odd KW design decision, even the later KW202 and 204 'separates' had to be netted onto the same frequency and they were in production into the mid 70s. Drake separates all allowed proper transceive operation.
The Vespa and KW 201 are really only the TX and RX parts of the KW2000 transceivers and had similar limitations - only one filter bandwidth meant poor AM and CW performance, 200KHz band segments meant part coverage of 15 and 10m and did I say no transceive !
APRIL 2016 - KW 1000 LINEAR AMPLFIER
With the next KW purchase it dawned on me that I had collected every item in this 1968 advert from the RSGB RadCom magazine from 1968. The prices were quite revealing as well - I had paid less in 2016 for each item than the 1968 price. The only trivial difference was that my KW Vespa was a Mk1 and not a Mk2 model (that had a sweep tube PA). The KW1000 was another stunning eBay purchase from ham about 60 miles away. The amplifier is in A1 cosmetic condition - which is very rare for any equipment over 40 years old. In true KW tradition the mechanical construction can best be describes as agricultural. There are no EHT interlocks and once removed from the case there is no cover over the PSU and the HV capacitors are facing upwards...so not a place to put your fingers. All the panels are held together with different screws, but at least its rugged!.
Initial physical checks revealed a number of things that would need attention. The most obvious was the that the anode RF choke was burnt in the very middle, this a classic symptom of a resonance that has resulted in severe RF heating in the choke. After chatting with other owners of this linear it looks as if either a different choke was fitted at the factory or it was changed at some point, the output RF choke was also missing and not knowing why I decided to change the HV 'doorknob' capacitor as well. All the HV caps tested OK although the balancing resistors are quite low value at 25K..so quite a bit of heat. I'll make up a PCB with modern caps and higher resistors at some point. My next mod before switch on was to insert an 800mA fuse in the EHT in series with a 10R 'glitch' resistor to limit the current should there be a tube flashover. I wound 2 different anode RF chokes - the first was close to the Heathkit SB200 design of 50 - 60uH, this worked OK but I was concerned that the inductance was too low for 80m and there could be RF on the EHT smoothing caps (despite extensive decoupling), in the end I went with a value over 120uH and a winding gap in the middle. I couldn't tell much difference but the engineer in me feels better !
Pictures of new choke and the burnt one on the right. Good power out on 40 and 80 from the Chinese 572b tubes already in the amplifier...over 500W out when driven from my KW2000A
This Pic of the KW1000 linear shows the plastic sleeved 800mA microwave oven fast blow fuse, I have also added a high power 10R 'glitch' resistor to limit the current should the tubes ever flash over..not a problem years ago but Chinese 572 tubes are notorious for variable quality and cannot really be trusted. Those 25K balancing resistors sure do get hot..modern caps and higher value resistors to add soon
MAY 2016 KW ATLANTA
Next KW item added to the inventory a very nice KW Atlanta transceiver with matching external VFO, PSU and Shure 444 microphone. This has been well looked after and is in good working order. At some point in its past life its been modified to use 6146 tubes in place of the 6LQ6 'sweep tubes', this appears to have been well done and the power out on 40 and 80m is around 100w. There is very little restoration work to do, although as with all older kit I will change the PSU caps for more modern ones - and for some reason the HT choke in the PSU is missing. There are very few Atlantas on the air in the UK and little information on the web about them..initially aimed at the US market, KW did sell them in the UK from 1969.
The KW Atlanta is pretty much a direct component level rip-off of the USA Swan 500 ( I have checked the schematics!). OK so they look a 'bit' different, but the radio architecture, tube lineup, audio derived AGC, dial arrangement are all identical..I have no idea how KW got away with copying a US rig, knocking it up in the UK and selling it back in the US!. KW copied the PSU as well but made it cheaper (surprise), the smoothing capacitors are all held together with cable ties and one bolt. The carrier 'bal' control is a nightmare in 'tune' mode - all the way left does not mean OFF, thats in the middle..turn all the way to the left and your back to lots of anode current...caught me out
The Swan 500 manual is a delight and I could probably use it to fault find the Atlanta, pity KW didn't copy that as well !. To cut cost the Swan design doesn't have any crystals as a premix to a 1st IF, instead the VFO frequency is switched by a bank of caps - of course KW copied this as well. Its a cheap 'Single Conversion' design with drift and poor dial calibration on 10m, lots of VFO trimmers, and the pi tank is used on receive as well as TX. Having said all that its fine on the low bands and the audio is very good if you back off the RF again to stop the audio derived AGC pops. Now I know why I love my Drakes so much. I have included a pic of the Swan 500..same radio but better built. I don't own a Swan!!
In Jan 2017 I noticed a problem with the Atlanta that had probably been getting worse since I obtained it..the S meter would gradually move upscale as the rig warmed up - as if the RF Gain was being backed off. A blip of the PTT put the S meter back to near zero (if no signal was present) and then it would gradually move upscale over 15 mins. This was clearly an AGC fault as the rest of the radio was fine. Before pulling the radio apart I searched for AGC faults on the SWAN 350/500 and sure enough Chris GM3WOJ (also an avid KW collector) had come across the same problem in a SWAN. There is some sort of diode clamp in the AGC circuit (not sure what it does - there is no info in the manual)..but if the diode leaks a tiny bit it gradually deafens the receiver. It took me a few mins to find it (no layout diagrams exist), but I changed it for a 1N400x to see what would happen...problem solved
KW TUNERS AND POWER METERS
Loads of Hams in my early years bought a KW'EZEE' Match, it was the only easily available balanced tuner without a lossy balun. Power handling was bit limited, 100 - 200 W at the most. It could arc over in some matching situations with too much power. Still sought after - although some just ask too much money for them. KW103 Power / SWR meter has been in my possession since the 70's. KW did put the match and the meter into one box (KW107/9), but people ask silly money for them (more than I have paid for a complete transceiver in some cases). After bartering unsuccessfully with a trader for a repainted KW101 SWR meter (he wanted £20 I offered £15) at the Eastbourne Rally in 2016 - he told me 'its KW mate and collectable'. Funny thing is one went on eBay for £10 a few days before, I gave up and walked away..same rally £20 for a kokusai filter, trader would not take £10. I paid less on eBay. Get real guys - selling old ham radio stuff is a hobby - not a business