1979 RCM&E home-build 35MHz RC system

[Anthony Pattison 1]

I'm looking for a copy of the articles on the RC system which appeared in RCM&E from May79 onwards. I particularly want the circuit diagrams if anyone has copies? Cheers

Edited July 15, 2023 by Martin Harris - Moderator
Removed email address to avoid attracting spam

[John Lee]

The articles were run from May to August 1979. I have scanned copies of the magazines, each of which have a file size of about 60mb. I'll drop you an email which will enable you download them from icloud for 30 days- they are too big to send as attachments.

 

Meanwhile here is a copy of the Tx circuit diagram:

 

 

PS I've asked the mods to delete you email address rather than leave it on public view for the spammers to harvest!

Edited July 15, 2023 by John Lee
PS added

[Engine Doctor]

Back in the 1960 when RCM&E was in a smaller format they included plans for a small tx that fitted into a tobacco tin . Does anyone remember this ? I built one but had very limited sucsess and range . I tried it with model boats  but still range was a problem . 

There were some excellent projects in the mag back then due to the high price of comercially produced items. 

[John T]

Here's to original PCB layout to show how things used to look before surface mount technology arrived.

[MattyB]

My Dad still has his (much modified) one of these sitting in the back of a cupboard somewhere!

[gangster]

Brilliant radio system. I have still got mine and have been meaning to fly with it again. Way ahead of its time with 8 channels,mixing of any two channels, rates,reversal,throw and end point adjustment, battery alarm roll buttons and many more features. How many other radios had all this in 1979

[gangster]

There was a myth that the receiver was wide open to interference due to lack of front end tuning. I flew mine on split channels at the peak of the CB boom initially 27 MHz and later on 35. Never had a glitch. Probably had more use than any other radio I have ever owned

[RottenRow]

How did the RCM&E system get around the tighter frequency spread requirements when 35MHz was introduced? Everything had to be type approved then, with a yellow label attached to the tx case.

 

I built a couple of Micron systems in the very early eighties, the PL-7D and the later RCM version that was featured in Radio Modeller at the time. I still have them, and all of the building sheets etc. The later one also had rate switches and channel mixing. Servo reversing was achieved by reversing the plugs of the joystick pots where they connected to the encoder board.

 

For 35MHz use, Micron sold the RF transmit board as a pre-built and pre-aligned item, so it was correctly tuned and complied with the regulations, with guaranteed 10kHz spacing. A yellow self-adhesive ‘type approved’ label was included to be stuck on the tx case.

 

There was no such requirement with the receivers, as misalignment would only affect the user, not anyone else.

 

If required, these txs would be easily converted for 2.4GHz use, using one of the FrSky hack modules or similar.

 

Brian.

[John Lee]

For the 35Mhz conversion they had half a dozen agents who could check the alignment and issue a Type Approval Certificate.

 

From the April 1981 RCM&E:

 

Edited July 15, 2023 by John Lee
Typo

[RottenRow]

Thanks John,

 

That’s very interesting. I see one of the approved agents was Modelgear in Leeds. I used to buy servo kits from them. They used the SLM mechanics.

 

Although not practical nowadays, building your own radio and servos did give a good insight into how everything worked, and was cost-effective when compared to the commercial brands.

 

Brian.

[John Lee]

Quite agree Brian.

 

I dabbled with home built gear in my youth, then my first ‘modern’ radio was a Waltron 4-5. I could only afford 2 servos initially and added Modelgear ones from kits as the pennies permitted. I’ve still got a retract servo that I built back then but I can’t see that it will ever see a model again!

[Wookman]

I built a receiver or two back in the day, but when the little Hitec 5 channel came out at a price that was less than the cost of the components and hardware for the homebuilds that was the end of that.

[Anthony Pattison 1]

I had a few of these sets back in the day and they were very good. John has sent me the pdfs of the articles so I can look at tweaking a couple of old receivers to 40MHz for use on an old aerokits crash tender for my grandson...

[Robin Colbourne]

13 hours ago, Engine Doctor said:

Back in the 1960 when RCM&E was in a smaller format they included plans for a small tx that fitted into a tobacco tin . Does anyone remember this ? I built one but had very limited sucsess and range . I tried it with model boats  but still range was a problem . 

There were some excellent projects in the mag back then due to the high price of comercially produced items. 

Engine Doctor, Do you mean this one on page 376 RCM&E December 1960

Edited July 15, 2023 by Robin Colbourne

[Phil Green]

For anyone interested in homebrew gear (its all I fly) hop over to singlechannel.co.uk  (its not all S/C!)

You will be amazed at the state of present-day homebrewing 😀

Cheers

Phil

[Engine Doctor]

10 hours ago, Robin Colbourne said:

Engine Doctor, Do you mean this one on page 376 RCM&E December 1960

Hi Robin . No not the one. It was designed to fit into a tobacco tin , 4 oz tin I believe. If my memory is correct  It had 2 or 4 push buttons on the front and battery was a PP3 9v .  It was i think o er a couple of editions an had a section on making the PCB using Ferric Chloride thst you could easily buy from the local chemist. You could also buy Ether easily for making diesel fuel for oyr engines. 

Exciting times then as there was always a parts list and a local radio shop near Clapham Junction in Falcon Road where you could buy parts although pockey money in those days meant a long build time. 

Thanks for looking. E.D.

[Phil Green]

20 hours ago, Phil Green said:

For anyone interested in homebrew gear (its all I fly) hop over to singlechannel.co.uk  (its not all S/C!)

 

Sorry, wrong link, should have been http://mode-zero.uk 

[Anthony Pattison 1]

Glad to see there are other oldies still interested in these old designs. I now have all the original data plus the update article for 35MHz so I'm planning to convert a couple of old RCM&E receivers to 40MHz for some old boats for my grandson - already have a couple of old 40MHz Tx. Much more interesting than just sticking in modern 2.4GHz stuff and being a Yorkshireman I can save a bit o'brass too! 🙂  Many thanks John for the articles. Tony

[Phil Green]

For anyone less confident with the RF side, tuning and set up, you can use commercial 35Mhz modules such as the Hitec HPF-Mi or Jamara, with a bit of sleuthing these modules can be found new in their original packaging and usually supplied with a crystal.  Many conversions have been done this way, my own 27Mhz KO DigiAce for example is converted to 35 using a Hitec module.  All they need is a 3 wire connection, power, ground & PPM - plus of course the aerial !   (a Hitec Optic-6 aerial is the same length as the DigiAce 27)

Many options, this is one of the easiest 🙂

Cheers - Phil

 

Edited July 17, 2023 by Phil Green

[Andy Stephenson]

I needed a really small receiver for 35MHz but the only one I could find was on 40MHz one, so I converted it to 35MHz simply by using a 35MHz crystal, no retuning necessary. I passed the range test no problem.

[Phil Green]

The little Corona 35 receivers were (are) very good, I liked the synth ones and bought a few RP4S1's back in the Cod days

Sorry I posted the wrong link again, dunno whats up with me...   heres the DigiAce conversion:

 

[Anthony Pattison 1]

Full RCM&E articles attached. RCM&E radio system(1).pdf

[FlyinFlynn]

9 hours ago, Phil Green said:

, dunno whats up with me...   

 

Anno Domini perchance?   or maybe a more chemical related problem? 🙂

[Masher]

12 hours ago, Anthony Pattison 1 said:

Full RCM&E articles attached. RCM&E radio system(1).pdf

Thanks for posting this, great memories as a young engineer knocking one up. Used to pop down to SLM most lunchtimes buying bits of plastic and tin.

Don't suppose you have the Practical Wireless version too by any chance?

Thanks

[Andy Stephenson]

I remember SLM in Cheltenham, They seemed a little irritated when I turned up unannounced to buy bits, although they always obliged.

Those were the days when every man and his dog were making 27MHz radio sets and they had plenty of customers for the necessary hardware, cases and servo parts etc.