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[stallspeed]

Dual coversion crystals are just to a narrow tolerance and should be in matched pairs.
They will work in  single-conv receivers.

Don't take every forum post as gospel truth.

Your Ebay listing to me said dual conversion :-
Range: 800M
Narrow-band
Microprocessor decoder
HIgh inter-modulation and interference suppression
High adjacent channel selectivity and interference rejection
No servo jitter when the transmitter is switched off
Small dimensions and weight
Compatible all FM/PPM transmitters
Uses mini or standard sized crystals (not included)

[sweed73]

can you have a look at this set, its the same rx the crystal has su on it ? mean anything,
http://cgi.ebay.co.uk/Radios-Sunupp-40MHz-4Channel-Transmitter-Receiver-US_W0QQitemZ350170734479QQcmdZViewItemQQptZRadio_Control_Parts_Accessories?hash=item350170734479
if the crystals tomorrow don't work i'm going to get a cheap set like this to get started.

[DickyD]

I should forget all this on here and take it all to your local shop and let them check it out.

[sweed73]

how about converting it into a viking funeral pyre ship, complete with tx.
should only take a second and would at least bring me some enjoyment.

[Philipsparker]

how about converting it into a viking funeral pyre ship, complete with tx.
should only take a second and would at least bring me some enjoyment.

No, just go to your local model shop and buy a proper transmitter that they can prove works with your reciver. Or just write the whole lot off to expereince and buy a Spectrum 2.4ghz set which probably works out cheaper if you need a lot of channels. That way you are future proofed and can get back to modelling instead of trying to make eBay gear work ! 

What were you going to operate on them anyway ?

[wideawake]

how about converting it into a viking funeral pyre ship, complete with tx.
should only take a second and would at least bring me some enjoyment.

Sadly I think that might be the best bet     My advice would be to go and buy a complete rig including TX and RX.  That way you know they're compatible.  I understand how these things work (at least I think I do) but I'd not bother with all this faffing about given that basic 40MHz sets are becoming much cheaper these days.   That gives me the chance to get on my soapbox and say that if you can afford a bit more then I'd go for 2.4GHz equipment and forget crystals for ever  

HTH

Guy

[red181]

With a rc boat or car, the throttle needs to self centre, take your hand off the stick, it returns to centre (and stops!)

Why?  All of my boat transmitters have ratcheting throttle sticks, I think it's much easier than keeping a constant pressure on the stick. It comes down to personal preference.

Peter.

Yes it is personal choice Peter, however I think you will find that every single rc plane or heli tx is ratchet none self centre, and "virtually" all shop bought car and boat tx is self centre, the original author appears to be a novice, so lets not confuse him eh?

Good points re the 40mhz and 35mhz, I forgot to point this out, however some really cheap and nasty helis and planes from the likes of (oops nearly named large retailers!!) sell cheap junk rc stuff operating on 40mhz.

[sweed73]

got my single con futabo crystals today, still doesn't work,
the bloke i bought it off won't reply to emails for info on crystals,
got a nagging feeling he replaced it because it doesn't work.
going to buy a complete set tonight,
might have to be a cheap one again but i'm going to buy the lot together as a set.
oh well

[sweed73]

just spotted a pic of tx and rx for sale , includes single con crystals in both,

[stallspeed]

Well I think you have,

• a working Futaba or Hitec clone transmitter,therefore works with unbranded negative shift crystal.
• a working dual conversion(High adjacent channel selectivity and interference rejection ) receiver needing a dual conversion crystal based on the Ebay description.
• two matched crystal pairs,most likely negative shift to be Futaba compatible 

But
With each frequecy,you need to get a dual coversion receiver crystal,and probably the Futaba one.That is the downside of getting a dual conversion receiver. The benefits are well documented elsewhere.

I further think your transmitter and crystal pairs will be compatible with both the set you have seen and the set you gave a link to yesterday.

[DickyD]

Buy new !!

[craftysod]

Agree with Dicky,what your gonna spend to get it working,you can buy a 2.4 set for £30-40 now

[wideawake]

Agree with Dicky,what your gonna spend to get it working,you can buy a 2.4 set for £30-40 now

I agree that the best approach is to buy a complete set from a reputable supplier. that way you know that all items are compatible.   just for interest I had a look on the Howes website and was shocked to see how much prices have increased due to the poor exchange rate.   Even so a 2 channel set can be had for £36.   Anyone who had the courage to buy a DX5e at Warwick last autumn for around £55 did well though.   Howes list it at £85 today!    WRT 2.4GHz for £30 or so, I've just ordered one of the Turborix sets and am waiting for it to arrive.   It takes a different approach with no menus etc but programming via a USB link to a PC.   I'm waiting to see if it's CE marked and therefore officially legal in the UK.

HTH

Guy

[craftysod]

I had noticed that the prices have jumped up a lot Guy,for the spektrum sets,will wait for your conclusion before i get a Tuborix set,
as even though they are cheap
are they any good
are they legal in uk
if not ,buy another rx for dx6i
Mark

[wideawake]

I had noticed that the prices have jumped up a lot Guy,for the spektrum sets,will wait for your conclusion before i get a Tuborix set,
as even though they are cheap
are they any good
are they legal in uk
if not ,buy another rx for dx6i
Mark

Hi Mark

Yes I suspect that it won't be CE marked.   If it's not, my main concern is that it may produce more than the legal power limit.   There's a reference on the website to "up to 800mW".   The UK limit is 100mW.   

Guy

[sweed73]

Can some one point me in the direction of a set that i can buy online,
needs are
1)   3 channels or more
2)   decent range
3)   for use on a boat in the uk

a link would be great then i can get something ordered and get all the rest back on fleebay.

thanks

by the way what does su stand for on a crystal

[craftysod]

Sweed
To get you out of trouble,buy a 2.4ghz set,no crystals to play with.
What is your budget to spend,to give members a price range to advise you,
Guy has recommened the spektrum dx5e which he has tested and gives more than you need,
or as said from others buy a complete set (non 2.4) tx/rx from shop retailer.
Put ad in wants/swaps for radio gear on the forum the guys on here must have a spare set to sell,
and they are honest
Mark

[wideawake]

As Mark has said, I'd go for 2.4GHz even though the prices have gone up.   However I had a quick look around for 40MHz sets and the most reasonable I found meeting your spec is the Hitec Zebra 4 Channel 40 Mhz Radio Control Set With Servos.     I'm not going to suggest a particular retailer but  Google for it and you should find it at £47.

HTH

Guy

[stallspeed]

I had noticed that the prices have jumped up a lot Guy,for the spektrum sets,will wait for your conclusion before i get a Tuborix set,
as even though they are cheap
are they any good
are they legal in uk
if not ,buy another rx for dx6i
Mark

Hi Mark

Yes I suspect that it won't be CE marked.   If it's not, my main concern is that it may produce more than the legal power limit.   There's a reference on the website to "up to 800mW".   The UK limit is 100mW.   

Guy

The 800mW is likely to be a typo because 800mW would would mean 70% of battery power is converted to rf power.No way.
I have not looked at other 2.4G radios in depth but they should have a similar efficiency(post coversion).
SU possibly Single conversion sconv or synthesised crystal (i.e. no crystal) or laxative(suppo crystal) or crystal for supo receiver or superhet crystal

2.4 G is forgiving if you are sloppy with motor suppression but not with subs.
40 fm with a dual conversion receiver  gives what it says in the blurb.
The complete set you listed and other sets based on single conversion 40Mhz receivers do as far as the eye can see.
40 or 27 AM don't get a mention.

[sweed73]

on the 2.4 sets do none of them have crystals, do you pair them with the reciever themselves.
does this mean a 2.4 can be used for land, sea and air ?
just seen a set for around £50
EK2 0404G  for the tx
EK2 0424 for the rx
this is advertised for a heli though,
will there be different sets for a boat.

[omra85]

This is another set for a small helicopter.
Most of them are only ever used up to 20 metres away from the Tx so don't have to have a "normal" range.
I have a similar one (for a 'toy' heli) which I wouldn't dream of putting in a boat as I wouldn't trust it for range.
2.4GHZ is legal for air (planes and helis) and surface (cars and boats) so a good one will be useful if you ever decide to diversify.

Bite the bullet and get a Spektrum DX5i, or go 40MHz with Futaba, Hitec, JR.

Danny
Oh yes - the 2.4GHz operate in a different way so, no you don't need any crystals (or to worry about frequencies)

[craftysod]

The 2.4ghz do not use crystals,but come with a tx that you bind with the rx (complete set).
Forget about if its for a helicopter,they have lots more settings than a boat,unless you want it to leave the pond,
my dx6i could drive me to work if i let it  

[Bartapuss]

I got one of those Sunupp 40meg RX's and it also did'nt work, contacted the seller, did not get a reply so that speaks volumes to me 

[stallspeed]

There are so few English language rereferences to Sunupp and so many possible crystal/transmitter permutations that I would not even buy a comlpete Sunupp transmitter/receiver/crystal from the Ebay suppliers.
 As far as the parts you have,if the vendors can't or won't tell what associated branded r/c gear works with the individual elements then the previous Ebay auction winners might.

[wideawake]

on the 2.4 sets do none of them have crystals, do you pair them with the reciever themselves.
does this mean a 2.4 can be used for land, sea and air ?
just seen a set for around £50

That was probably the Spektrum DX5e but the price has gone up, though I'd still recommend it (except for submarines!).  Without indulging  in too much self-publicity, if you want an overview of the present state of play you could look at this link

http://www.modelboats.co.uk/news/browse.asp?at=12&p=4

and read the article on r/c today.

The site's well worth a look anyway since Colin has given it a much needed  "wash and brush up"!

HTH

Guy

Guy