The Wireless Reception set R5223, the poor mans' Larkspur

ralph klimek may 2007

This web page is devoted to the Wireless Reception Set R5223 made by TCA Australia.

Introduction.
The  Reception Set R5223  is a receive only device. It covers the entire HF spectrum from 1.5Mhz to 30Mhz in 30 odd bands. It was designed to receive AM voice, CW, and MCW transmissions. It is all valve based with an advanced double conversion super heterodyne design. It lacks a product detector. it could be powered from a vehicle battery or mains.

My connection with this set.
I acquired this radio from "The Lizard" VK3YRU nearly 30 years ago. It had been heavily Hamified, perhaps the most objectionable Hamification was the removal of the original military grade knobs on the front panel for cheap-n-nasty placky consumer grade knobs. And it had been painted baby blue. Yeech! I originally bought it for $20  on a what you see is what you get transaction. It came with the manual ! and it wasnt working.

I first saw sets of this kind for sale in the disposals store and expressed interest in one. The Wise Old Ham warned me off it, saying that I couldnt afford it.( I was 14 at that time ) That part was true, they cost more that I was worth. I also could not have afforded to keep it running!

Let me be the first to say that the electronic design of this radio had left nothing to chance, it was good as the state of the Australian art permitted in the early sixties, and some aspects were both very conservative and very innovative. Coverage of the entire HF spectrum in 30 bands was unique and it wasnt a Collins or a Racal. It was sensitive, a test lead jabbed in the antenna socket made it a good general coverage shortwave radio.  My gripes are many and manifest. I had been spoiled, I was by then accustomed to Larkspur build quality and the build quality of this radio was only slightly better than consumer grade electronics. The components were thermally underspecified, consumer grade electronic components had been used instead of mil-spec devices. Somebody had tried very hard to make a dependable and best of breed radio but clearly the bean counters and management had won this battle and they produced a lemon instead; in the way that bean counters and managers only can when they are allowed  to make engineering decisions. The only Larkspur like element in this design was the fully sealed die-cast enclosure and ruggedised front panel.

The maintenance philosophy of this set was like eighties computer systems, fault diagnosis to the smallest FRU (Field Replaceable Unit). The FRUs in this set were small sealed and soldered up metal cans, with only the valves, control shafts and terminals exposed. The terminals were not plugs and sockets ( ala Larkspurs ) but solder terminals....this is arguably a good or bad thing depending on your point of view. Actual Maintenance was restricted , by design, to valve replacement, and if a component internal to one of these metal cans was dead, you were compelled to replace the entire can. This is actually a good operational model, but for the collector/restorer/enthusiast/Ham is a total pain. It is thus totally impossible to probe the circuits. I had to build a valve socket extender so that I could measure the voltages under the valve pins and infer the fault. The only concession made to would be maintainers was a built in multimeter (complete with probes!) and the ability to monitor the plate current of every valve or assembly from a front panel control and the built in meter.

Practical maintenance for people like us requires you to open the tin cans. This destroys the structural integrity of the can so you must be carefully as controls are also attached to the cans and the cans dont have anything like an internal sub-chassis.  Much to my annoyance and chagrin, where one watt resistors should have been used, quarter watt resistors had been used, and of course they were all out of spec or just burned.  Cheap and nasty paper capacitors had been used for bypasses but fortuneatly  good quality silver micas used for resonant elements and other places where the value of capacitance mattered. The worst components used were tuned inductors in the IF stages and the tuned IF. Never attempt to adjust these, they just disintegrate ! I did and as a consequence had to build my own IF strip. I have had to open every can and replace mostly everything. One shouldnt speculate what negative  impact this set had on actual military operations...it could not have been good.

The circuit diagram I have only as a large fold out sheet and presented here are pictures of it taken with a digital camera.  The rest of the manual is scanned on a old HP scanjet 2 and presented here. The manual is very verbose and has an elaborate tune up procedure. In an off the cuff way it mentions that the radio  is fundamentally unrepairable. Never be tempted to retune the IF or VIF inductors, they will break. The RF unit inductors may be retuned without risk of damage.

If you have one of these lemons, do take the trouble to restore it, you will get a superb general coverage short wave radio out of your efforts. Replace all paper capacitors with polyesters and any resistor that has to dissipate any power , like screen grid resistors should be wire wounds or 1 watt metal films , if you can get them. It used only consumer grade valves, thats a pity but the upshot is that they are all still available from ham bottle banks, only the 6AV6 and 6BE6 pentagrids may be hard to get now. All the bottles have CV numbered mil-spec equivalents and substitution is recommended by me.

My own Hamifications would be re-engineer the DETECTOR and AGC units so as to provide a product detector. As it is, BFO injection upsets the AGC requiring you to use the manual RF gain control. This mis-feature is common even in the superior built Larkspur radios.  The clever feature of this radio is the use of only 9 crystals to generate all 29 of the first  mixer master oscillator signals required for 30 separate bands. In them-thar days the cost of these crystals would have been significant. So far I have had to rebiuld the IF amp, the detector agc unit got a ceramic resonator i.f so it has now a very decent AM general coverage response.

Reception Set SFT R5223,  5820-66-012-2952  1965 SER No  (unreadable)  

made by TCA Australia

Click me for hi resolution images of the inside of this radio.

Underneath the awful blue paint is the original army green. Someone, certainly not me , substituted yucky consumer knobs...lord knows why. Must have seemed a good idea at the time. If I could scrape off that blue paint without damaging the original I would.

Improved large schematic pictures.

This view of the schematics was photographed with a small pentax on this improvised travelling frame. This permitted the camera to be at a fixed distance from the blueprint for each picture. However when it came time to stitch the individual images together I found that the little pentax optio  is not a process camera.  Some assymetic scaling was required to get the image portions to line up was required.  I have left the image portions in this tarball if you want to print your own paper versions and stitch them together using traditional paper and scissors method.

 And , here is the entire manual. I had photocopies given too me when I purchased this nearly 30 years ago. The copies came on that horrible old zinc oxide coated liquid toner machines. The paper still has the unmistakable choking stench that these machines emitted. The images were also rather lousy. They have gone dark over the years but are still legible, not good enough for OCR , so what you see is all you get. There are over 100 pages, so I will not html-alize them. Download the complete tarball here. I have edited all of the images using the GIMP to clean them up, and most are now actually readable. Now with all of 30 years worth of grime are gone  the total download size has also been reduced by some 6 megabytes (at no extra charge!) if you have downloaded my original tarball, do it again. It will be worth the wait.  The images have been cleaned up with the GIMP "dodge and burn tool" which literally wipes away "grime" from grayscale images. This is the final graphical edit of these files and just about all of them are now printable and legible with a good graphics viewer.  These images will ultimately be set to RoyalSignals and the BAMA.

tarball of scanned reception set R5223 manual pages 

this one has been cut and pasted together from assorted blue print cutlets