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Author Topic: 27 MHz the forgotten frequency?  (Read 2414 times)

GG

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27 MHz the forgotten frequency?
« on: July 21, 2019, 11:58:48 AM »

I sometimes get funny looks at the lakeside when I extend a transmitters aerial with its brightly coloured frequency ribbon fluttering at the tip.  After a moments puzzled expression, the other modellers remember the time when all RC transmitters featured a long shiny telescopic aerial before the current rage for short black ones.  The also might remember all the fun of tracking down the person who had wandered off with the frequency peg they wanted to use?


Having a couple of admittedly old but still perfectly function 27 MHz outfits, I'm reluctant to discard them just for the sake of fashion or modernity.  They and my 40 MHz gear, are also preferred for RC submarines.  So, I was a little worried to read in a U.S. hobby forum that there was still a problem with CB (Citizens Band) radio on the 27 MHz band.


An old frequency monitor (just a radio that covered the 27 MHz band as well as others) was pulled out of storage.  After installing a fresh battery and switching on I was greeted with total silence across the 27 MHZ band. Just in case it was faulty, a transmitter was switched on an rewarded me with an earful of load buzzing at the right spot on the dial.


I'm not foolish enough to think this means that in the UK there will be no interference on with 27 MHz RC outfits but it is encouraging.  Perhaps America is still the stronghold for CB "good buddies" whereas in the UK people find mobile phones more convenient?


Whatever the reason, old fashioned or not, I'm going to carry on using my 27 and 40 MHz outfits until they die.  The only precaution is to check for anyone else waggling a long shinny aerial skywards before I switch on.
Glynn Guest
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Capt Podge

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Re: 27 MHz the forgotten frequency?
« Reply #1 on: July 21, 2019, 12:28:22 PM »

I've still got my 27mhz futaba outfit as well Glynn.
I don't use it nowadays however, I do take it with me on every visit to the lake as a backup,  should the 2.4ghz develop a fault.


Regards,
Ray.
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roycv

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Re: 27 MHz the forgotten frequency?
« Reply #2 on: July 21, 2019, 03:19:04 PM »

Hi all 27 and 40 is all I use, all also both on AM and FM.  I have a few sets of 27 FM crystals to last me out but loads of AM ones. The 27 FM sets are multi-channel and work very nicely, my favourite is an old Futaba M series in brushed aluminium.
In another thread I posted that 35 Mhtz sets work very well with 40 Mhtz FM crystals in so do not pass up the chance if offered of a redundant set.  My Fleet 40Mhtz set is marked underneath as 35Mhtz, so there is not a problem of approved RF emissions.

 Just setting up my near completed Ogdensburg with 27 Mhtz gear.  It has been on the top shelf whilst I did a commission job but stayed there.  Got it down for completion yesterday.  I have all the 'O' gauge vehicles, all left hand drive as well!  I am planning to stick them in place with clear bathroom sealant.


I find the only drawback with the old gear is the AA cell connectors in the Tx's. They can go green and lose their plating, best to remove batteries when not in use.  Also need to check for black wire disease.
 If I have to scrap one I take out the connectors, but I have one set that has a non-shaped flat battery place and I am going to fit an 8 cell newish AAA welded pack in there with some sponge positioning pieces.

With the current rechargeables getting higher in capacity the old 70ma charger takes too long.  I have got a 4 to 8 cell mains charger and feed this into a multiway adapter.  One of the outputs is the single spike connector as on the slow Tx chargers.  Much quicker that way, I also charge Rx batteries the same way.
I have to say though that I prefer to charge Tx's before going boating so the high capacity cells are not that preferable and I am content with 1300mAh ones which last almost all day anyway.
Regards
Roy


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Colin Bishop

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Re: 27 MHz the forgotten frequency?
« Reply #3 on: July 21, 2019, 03:40:20 PM »

I was using my Futaba M series Steerwheel at Bushy Park this morning to control my Caldercraft Cumbrae built in 1992.
Colin
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GG

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Re: 27 MHz the forgotten frequency?
« Reply #4 on: July 21, 2019, 05:33:32 PM »

Glad to hear I'm not the only one still using such "oldfashioned" RC gear successfully.  I hate to think how many such sets were discarded or forgotten about in the rush to  (Short Black Aerials).


And Roy, I too happily use 35 MHz receivers with 40 MHz crystals, was told about it by the importer of the gear I was using when trying to buy a spare receiver many years ago.  In fact I reported so in a "Mooring Post" item back in Oct 2015.  Enjoy the Ogdensburg as there is unlikely to be anything else like it published.


Glynn Guest
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Colin Bishop

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Re: 27 MHz the forgotten frequency?
« Reply #5 on: July 21, 2019, 05:52:09 PM »

27Mhz rules OK!

Colin
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roycv

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Re: 27 MHz the forgotten frequency?
« Reply #6 on: July 21, 2019, 07:10:03 PM »

Hello Glynn, re 35 to 40 Mhtz, I knew I had read it somewhere and I was acting on picking it up from a reliable source, so thanks.  I opened a separate thread on doing this a few months ago and it met with a frosty reception.

I have a 40 M. Hitec Ranger 3 with a flick slider control right where my right thumb sits and I use it to flatten a flying jib via a standard servo.  No other sets like it so have to keep it serviceable.  I have another with a rotary 3rd. ch. control but it is not the same!

I used the Noggsund plans and Ogdensburg as exercises in only using the contents of my workshop for everything including wood, motors, props, shafts, batteries, fittings, all except glue and paint, so not much outlay there.  But a lot of satisfaction.

regards Roy





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malcolmfrary

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Re: 27 MHz the forgotten frequency?
« Reply #7 on: July 21, 2019, 09:06:23 PM »

In the US, with its larger distances, there was and probably still is some point to CB as a means of communication where cell coverage might be patchy. 
CB in the UK was a brief passing fad, overtaken by easier and cheaper ways of doing the same task. i.e. cellphones with cheap contracts.  Those who would have been CB-ers can now be seen texting and walking into things. 
The only CB-ers who are likely to cause problems with legal users are those who want extra range and buy power amplifiers to boost output.  These are untuned and increase not only the tuned frequency, but also any unwanted signal on adjacent frequencies.  The transmitters tunng keeps these in bounds, but amplifying them turns them back into signals that are at a level where they do cause interference.
Over here, 27MHz toys are more likely to create problems, very few being tuned to what is conventionally regarded as a channel, but using the entire band.  This is cheaper to make both for transmitters (plus they run low power) and receivers, which do not need the same number of parts to get selectivity.
Putting a 40MHz crystal nto a 35MHz receiver might well work perfectly fine.  If it works, no problem, but never get the idea that it works with a transmitter.  While the receiver self checks in that it either works or doesn't, there is no way that somebody without the right test gear can check what is being transmitted.
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Peter Fitness

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Re: 27 MHz the forgotten frequency?
« Reply #8 on: July 21, 2019, 11:59:34 PM »

In Australia the 36 Mhz band is approved for RC, as well as 27 Mhz. I regularly use my Futaba 36 Mhz sets at our lake but the vast majority of members use 2.4 Ghz sets. Our frequency board still gets deployed each sailing day, but I'm often the only one using it. I do use 2.4 Ghz as well.


Peter.
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roycv

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Re: 27 MHz the forgotten frequency?
« Reply #9 on: July 22, 2019, 12:06:32 AM »

Hi Malcolm, my Fleet 40 Mhtz equipment bought new from the shop is marked 35 Mhtz on a label underneath.  I made the mistake of buying a stubby aerial which gave 20 foot range and was useless.

I went back to the shop but Mr. Olley refused to change it and I had to pay for a normal aerial as I needed the correct fitment to the Tx.  Water under the bridge now but I did not buy any more Fleet equipment.  Nice stuff though.
regards

Roy
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davidjt

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Re: 27 MHz the forgotten frequency?
« Reply #10 on: July 22, 2019, 09:34:55 AM »


hi,
I still use my 27mhz and 40 MHz am and fm  :-)) . I have also started on the 2.4 which I had 3 left me by a friend  who died , but must admit I like not having to check who is on what band. this using 35 MHz sounds good, as I have also got some of these, can I just put say hitec  40 mhz crystal  in transmitter and same in  40mhz receiver and it will work ? , 




david
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BrianB6

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Re: 27 MHz the forgotten frequency?
« Reply #11 on: July 22, 2019, 10:15:12 AM »

I have a 27 and 29 MHz systems but so less hassles with 2.4 gig.
Also I can sit in a chair by the lake and not be concerned about poking someomes eye out.  :embarrassed:
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malcolmfrary

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Re: 27 MHz the forgotten frequency?
« Reply #12 on: July 22, 2019, 10:37:14 AM »

hi,
I still use my 27mhz and 40 MHz am and fm  :-)) . I have also started on the 2.4 which I had 3 left me by a friend  who died , but must admit I like not having to check who is on what band. this using 35 MHz sounds good, as I have also got some of these, can I just put say hitec  40 mhz crystal  in transmitter and same in  40mhz receiver and it will work ? , 




david
NO.
Like I said earlier, putting a foreign crystal in a receiver has two possible results.  It either works or it doesn't.  Putting a "wrong band" crystal in a transmitter does not have predictable results, even if it appears to work.  You can have no idea what is being transmitted.  Just don't do it.


Brian - thats a good reason for the flag on the end - an alternative is a wine bottle cork suitably slit to fit the end of the aerial.  Practice golf balls and Kinder eggs work, but getting the cork is more fun.
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Subculture

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Re: 27 MHz the forgotten frequency?
« Reply #13 on: July 23, 2019, 09:41:17 AM »

I can well recall the days when 27mhz was all that was available at the lakeside, 40mhz not arriving until the mid to late 80's, and it was very expensive kit too.

The limited range of frequencies restricted the amount of models that could sail (these days it appears to be la mort!), and some modellers- usually yacht sailors- would hog a frequency for a whole morning.

I guess if the older kit works well, and does what you require of it then there's not much reason to change, but I'm far from nostalgic about old electronics.

justboatonic

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Re: 27 MHz the forgotten frequency?
« Reply #14 on: July 30, 2019, 09:32:34 PM »

I wouldnt say the 27Mhz band is totally quiet. There's still CB users out there using the old non UK frequencies. That said, you'd have to be unlucky to get CB interference on 27mhz when sailing.
But the reason I wouldnt use old 27Mhz is, its old technology. Huge aerials on Txs and Rxs for starters. I mean why would you watch 625 line tv nowadays?
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KitS

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Re: 27 MHz the forgotten frequency?
« Reply #15 on: July 30, 2019, 09:58:34 PM »


I mean why would you watch 625 line tv nowadays?


You may only have a 625 line set...............
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Regards
Kit

roycv

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Re: 27 MHz the forgotten frequency?
« Reply #16 on: July 30, 2019, 11:56:17 PM »

Hi all, It is easy enough to put a practice golf ball on the end of the 27Mhtz. aerial for safety but the other day I was 'helping' my yacht to return with the aid of the aerial.  Can't do that with 2.4 Ghtz!

I agree I also do not have a nostalgic view of old electronics and I can't say I think much of the current articles in Model Boats with large pictures of obscure old electronics either.  Waste of time on me and I used to have some of the gear.  If you want some nostalgia my vote is with the previous Flotsam and Jetsom articles.
regards to all,
Roy
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RST

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Re: 27 MHz the forgotten frequency?
« Reply #17 on: August 02, 2019, 09:05:27 PM »

I'm not a technophobe, or obsessed with nostalgia.  But I wouldn't change a technology "just because".  I"m still 40Mhz at home (more than 27Mhz pretty much only because the receivers are smaller, and I build smaller models these days).  I don't have any advantage in changing to 2.4Ghz yet as the sticks still go up and down and left and right just as well.  Depends though, I don't have local clubs so 'xtals are never a problem.  I've never whipped anyone with a traditional aerial -but must admit I can understand in a congested space:  I was in Jardin de Luxemburg in Paris cpl of months ago and survived watching round the pond for 20mins, but turned and walking away (got about 20 yds) and some little girl ran up and nearly took my eye out waving a 4' long stick she should have been poking her pond yacht with.  Took my glasses half-off like Captain Mainwaring, no reprimand or any form of quick apology when the parent retrieved the child 10s later of course!
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