hi guys, I have a futaba T6xap on 72 Mhz -freq. 72.750 Mhz - for which I need a couple of receivers. After trying to find a matching rx xtal, with no luck, I came across the corona synthesized rx, available in India. I was set to buy the corona RP 8 D1 when I read this review on hc

Quote
I purchased three of the RP8D1 receivers. I programmed all three with failsafe and test flew each receiver. The receiver has very good range and flew with no discernable glitches. The failsafe worked correctly when I turned off the transmitter momentarily.

However, the output signal only has about 100 steps for the 1ms to 2ms range of each channel. The old non-computerized transmitter and receivers I flew in the past had essentially infinite resolution. Newer transmitters loose resolution in both the transmitter encoding and in the receiver DSP filtering. The RP8D1 outputs are in 10us steps. 1ms/10us = 100 steps. With my Futaba 9C transmitter, this means the RP8D1 will not respond to the first couple of steps of trim change (each trim change results in abut 5us change in the transmitted pulse width).

The receiver is fine for sport flying but if you have a plane with sensitive controls, you will find that when you give a momentary up elevator or down elevator command, the plane will respond as if your servos had lots of dead-band.

As I mostly fly aerobatic planes was wondering if this would be an issue?   Has anyone had similar issues? And are there other synthesized receivers (not necessarily corona) that dont have this problem.
thanks in advance for your suggestions.

People on our field who use them on 40 and 60 sized planes seem to be doing fine with it, even in terms of trim to get their planes to fly level. 

But if you are trying to do high precision stuff (especially on larger planes), the "peace of mind" factor would be best with Futaba receivers themselves. So do you have Futaba receivers already, and you are only looking for crystals ?  Are they single or dual conversion ?

hi Anwar, thanks for your response. I have the futaba rx that came with my radio - its a R136 HP, dual conv. (I think)
The prob is that I have several planes and I take at least two to the field  - and have to move the receiver from one to the other - which is a real pain - Compounded by the fact that one of my planes is a biplane - sopwith pup - which needs the 4 struts and also one end of the undercarrige removed to take the bottom wing off to access radio compartment!     

I found several futaba rx's available here in the trade section but all with diff. crystals  was also considering the hitec supreme 8 channel -but that also requires a separate crystal - and I can find all other freq. except mine!

R136HP is single conversion.  The dual conversion ones usually end with "DP" instead of "HP".  Another way to notice them is that their crystals (original Futaba ones) have a red tag, while the single conversion ones have a black tag.

So it sounds like it you are looking for the entire receiver with crystal, and not just the crystal.  You can find them in local stores (cannot vouch if your frequency is available).

try ebay.com you should get tons of used/new futaba receivers with your spec. n need at believable prices !

ok thanks Anwar and Sahilkit, yes I need a couple of receiver with crystals matching my tx freq.
I want to try and find them locally if possible. Dont want to take achance with customs etc. And I am moving up to the bigger gas planes - flying a 26cc giles right now and have a 50cc edge that I am putting together.  So I guess I could buy the corona for the smaller glow stuff and look for futaba or hitec for the larger stuff?
Has anyone used the corona rx on the bigger planes, especially  gassers?

Actually they are not that common on ebay.com either   Just goes to show how much 2.4Ghz is having an impact.

http://cgi.ebay.com/Futaba-FM-Crystal-72-750-MHz-RX-Single-Conversion-Hitec_W0QQitemZ320467460033QQcmdZViewItemQQptZRadio_Control_Parts_Accessories?hash=item4a9d595fc1#ht_1794wt_935

If you get the above crystal, you can get another single conversion receiver either locally or elsewhere.  I see such receivers in local hobby stores.

The dual conversion one is also available on eBay (again, not many) :

http://cgi.ebay.com/Futaba-72MHz-Dual-Conv-Channel-48-Receiver-Crystal_W0QQitemZ200419323282QQcmdZViewItemQQptZRadio_Control_Parts_Accessories?hash=item2ea9ec2d92

But you have to ensure you get a dual conversion receiver too.

Go for either "HP" (single conversion PCM) or "DP" (dual conversion PCM, slight advantage over others) receivers instead of "F" (which is "PPM") on your larger planes.

Customs should not be a big issue on these small items (especially if you are getting only crystals from outside, and buying the receiver locally).

QuoteActually they are not that common on ebay.com either 

but i saw a good deal go by just a week ago !

Fact is that they are available outside, for good prices. For example http://www.helikraft.com, which is one of the shops we heli folks frequent, has Futaba crystals for good prices, but the issue is they don't have the right channel either.

Like I said, except for Corona synthesized etc as alternative strategies, 72Mhz is becoming less and less accessible.

We do have these available :

http://stores.shop.ebay.in/rcforallin_FUTABA_W0QQ_fsubZ499852010QQ_sidZ675641320QQ_trksidZp4634Q2ec0Q2em322



Rgds
Sai

Including the right crystal ? That's it then !

These are without  crystals.

Special offer for RCI Members  free Shipment 

thanks for all the info and the links Anwar. I have decided to try the corona right now and buy the futuba receiver soon locally (thanks Mr. Sai) - for my bigger gas planes.  I might get the crystal though.   

hi guys ,
so I got the corona rp6d1 receiver and immediately ran into set up problems. As per instructions
1. turned on tx with antenna extended.
2. turned on rx - led flashes twice
3. pressed the scan button for 2 secs -starts flashing 3 times - enters mode I
4. my prob is if I press the scan button again - the led starts flashing rapidly as it should in scan mode.  But then flashes twice and goes off instead of staying lit/locking on to tx

Instructions say to check the tx - but there is no prob with the tx.  - whats going on? Any help/suggestion would be greately appreciated.
thanks   

Check if your Tx is on PCM mode it has to be on PPM mode

thanks Mr. Sai. That did the trick!

Welcome my pleasure