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[roycv]

Hi all, I wonder how many of us still use 27 Mhz FM equipment?
I have a Futaba M series and also use Micron, all multi channel, Futaba with Micron Rx. is an excellent combination.

In the 100 page Model Boats Kits Special there is a RTR boat called Slingshot.  According to the text of the article it uses FM crystals and they will be available by the time the article was read from Ripmax. 27 Mhz FM crystals are like hens teeth!

I rang Hobby Store at Parkway N.W. London  and spoke to a very helpful chap and he said they did not have any. ( He actually uses 27 Mhz FM crystals himself, and has to buy direct from Hong Kong.)
But he phoned Ripmax and rang me back and said there were no plans at the moment to stock them.

BUT he gave me this site where you can get them from.

www.rc-mushroom.com

They are $9.51 per pair +p&p.  There is a choice of 9 crystals.

Regards to all Roy

[Youngat65]

Some of the Heng-Long tanks that have smoke and sound are 27mhz FM they do four different frequencys and I have seen them for sale at  www.tankzone.co.uk
                                                                                     Cheers
                                                                                          Bob B

[Fast Electricals]

Are you sure that you need FM crystals? The only reason why FM would differ from AM would be if the receiver used a different IF frequency from a standard AM receiver (455KHz) or if the crystals were a non standard size. 

Neil

[Youngat65]

Neil are you sure this debate has raged before on this forum I have tried Futaba m FM crystals in my Futaba m AM set and they just don't work I,m sure that this is too simple a statment and it won't be long before we get some technical statment telling us that there is no reason why they shouldn't work
                                                                                      Cheers
                                                                                         Bob B
                                                                                           

[Doc]

You ready for this?
Crystals can be 'cut' on one of three different axis (X, Y, Z).  Depending on how they are cut, some will not vibrate (oscillate) like they should, or at least where you want them to (frequency).  An FM crystal in an AM radio transmitter is probably vibrating/oscillating, just not on the channel that you can use (or even the same band maybe).  Sort of like using an infrared lightbulb in your work shop.  It puts out lots of 'light', you just can't see it.  Same for the radio's receiver...
 - 'Doc

Like french bread?  Long sandwiches or very small ones?

[MikeK]

Thanks Doc you explained it so that even a mutton head like me could understand and that's saying something  ::) ::)

Cheers
MikeK

[Youngat65]

Didn't understand a word     
                                             Cheers
                                                  Bob B G4UBM (useless,brainless,and mindless )

[HS93 (RIP)]

What never heard of 1st  2nd 3rd  overtones on xtals   peter G0PAH

[roycv]

Hi all, I did not mean to stir anything up!  But yes I do mean FM crystals, I keep 2 boxes for 27Mhz, one AM the other FM,  I did try experiments many years ago (like 20+) and they do not mix together.
 When desperate and I have not been desperate for a few years now, i have used reversed black i.e. swapping the rx and tx crystals over.  Anyone know what frequency this is?  I expect it is outside the permitted band but just interested.
regards to all  Roy

[Doc]

Roy,
You really didn't 'stir' anything up, don't worry about it.  All those guys with the weird letters/numbers after their names are just hams, and aren't exactly 'right' to start with, you know?  They just love to show off their knowledge of 'old' stuff, and don't really know if they are washing or hanging out, sort of.
As to what frequency a reversed 'black' thingy would be, I have no idea,  Don't even know what the 'black' thingy is anyway since we don't 'do' (mark) things that way over here.  I feel safe in hazarding a guess that it isn't 'legal', or in a designated channel though.  (Another one of those things I wouldn't worry about much.  The statute of limitations for prosecution has surely expired after twenty years.)
 - 'Doc / W5LZ
... yeah, I got them weird letters/numbers too.  Sort of like an infection, no telling where you'll run across them.

[Peterm]

Roy,  for what it is worth, if you reversed the crystals on 27 MHz AM, you would transmit on a frequency 455 or 470 KHz below that of the Transmitter frequency.   It does work, but with a shorter range, and of course is illegal.   That should put the cat amongst the pigeons.    Pete M

[Ian Robins]

Hi
halfords are selling six sets of 27mhz fm crystals for £6.99 at the moment so it must be worth trying if you have a cheep chineese radio set
ro88o

[roycv]

Hi all, I always miss these things!  The part number is 188284-0, but they are currently not in stock!
regards Roy

[tigertiger]

Hi all, I always miss these things!  The part number is 188284-0, but they are currently not in stock!
regards Roy

Roy
Have you tried a different branch.

I had a game of waiting for stuff to come into my local halfords. Then I was told they obviosuly were not selling and must have been discontinued as there were no poans to stock it.

I went to another branch in the same town and guess what they had lots of?

[bigH]

  I bought an ACOM 2 channel 27 am set a couple of weeks ago  and boy was I suprised when I opened it.   new box complete with EC mark that read 27FM and not only that but the TX  only has battery fitments for the usual 8 but the damm thing iwill only run on 12v.   And to top it all I can't remember where I bought it
( But then at 78 I sometimes forget my name)  bigH