Either way, 4-5MHz is an awful long way to pull a 35/40Mhz receiver or transmitter without modifications to the circuitry.

It's pretty easy to be fooled by what appears to be a peak in the receiver or transmitter's tuning but which actually turns out to be simply the point where a front-end or transmitter circuit's coil reaches maximum (but not optimum) inductance.

If Mossie's problems persist then I'd like to have a look at his gear and see if it's just a bad case of trying to pull from 36 to 40 or vice versa.

I decided to stick with 72Mhz because I knew that's the way they'd be coming from the factory for the US marketplace -- plus it gave me the versatility of using the Spectra module.

Hitec 35Mhz and 36Mhz receivers use the same component values. Each is factory tuned on its respective frequency for that country of destination. Taking a 35Mhz European receiver downunder, would only require a crystal change and retuning.
Hitec 40Mhz receivers have many component differences on the front end and are made specifically for 40Mhz use only.

wonder if the 72mhz spectra is approved for use here with the VMAA/FAI controlling body?
I think we only have 36 and 29? for the am flyers.
We are thinking of approaching them if the matter cant be resolved by the importer, more as a safety issue than anything.
thanks

HI all.

In my opinion the TX is the problem. For me at least I have come to the conclussion that its my QPCM transmitter that is making the problems.

Just a matter of where to get it fixed, and whats actually wrong with it except....low range, big glitches, problems with certain servo's, and the rudder moves when you move the throttle stick?(no mixes are on)..

Interested to know how you fix yours if you ever do!.

It is possible (with the syptoms you describe) that the transmitter's tuning is so far off (or has a fault) that it's causing abnormally high levels of RF within the case itself. This RF could affect the processor, producing the odd-ball behavior you describe and it would also explain the lack of range.

Can you swap the RF (frequency) module for another and check?

There are other potential explanations -- such as a cracked PCB trace or bad connection between the ROM daughter-board and the main processor board but unless you've had some experience and an anti-static work-area I wouldn't recommend DIY repairs.

.....XJet, it sure sounds like you really know what your talking about"like paranoid said"!.

Thanks again for your input.
Something sure is really wrong with my TX.

Unfortunatly I can't swap the RF module as I cant borrow or afford another one.
For now I might have to just let the radio gather dust, or use it as a wheel chock.

Also last night when doing some more testing I noticed that when I turned my QPCM TX on it splattered"caused interferance" with another model I had on the bench at the same time."the othe model is on different frequency with its own TX and RX".
The second plane is all hitec gear "Flash 5" and works fine,"flown daily". I had it powered up and sitting on the bench,,,,,, And I noticed that when I turned my QPCM TX on it caused massive iterferance with the other plane on different freq.QPCM is on .633and other plane .643.
So I ran inside and grabbed another Flash 5 TX that is also on .633" when I turned this TX on it caused no iterferance. So it would seem that the QPCM TX along with its other problems is transmitting way off frequency?.

Also during a range check with Qpcm tx it improves from 5meters with arial down to about 10meters if I hold onto the arial with my hand. With arial pulled out about 15cm"the first thin bit only" It, the range then improves again. to about 20 meters. By the way my 2 Flash 5 TX's with arial all the way in work fine for about 60meters.

Thanks for your help EXJET.

It certainly sounds like the transmitter's RF module is at fault -- nothing that goes on outside that module should cause your transmitter to splatter like that.

Try removing and refitting the RF module a few times (with the power off of course).

It's possible that it could be something as simple as a poor connection on one of the pins and a bit of "exercise" might clean the tarnished surface enough to allow proper contact.

smoothpass, This is exactly whats happening to our 2 qpcm's even down to the rudder glitch that can be clearly heard on my heli(noisy digitals) when using throttle, although the rcd3500 rec. hasn't given me many problems at all, unlike qpcm & electron6 & 555.
XJET----- HELP!!!! my planes are gathering dust .
Wonder how mossie went? Is it worth sending them back to model engines with your recommendations here?
thanks

XJET, you might know? I borrowed a mates Hitec programmer for a few days and used it to measure the pulse of the TX for each channel.

I noticed for example that when I checked say the rudder or elevator the readout would fluctuate when I move the throttle stick?. When moving the throttle stick it affects pulse of other channels, only by a 1 or 2 digits, but it does never the less. I then checked some of my flash 5's, they do it too!. Then I checked one of my JR radios, and it was perfectly stable, as in that pulse was not affected by any other channel, only the stick in command for that channel.

So my question XJET,,,, is it normal for the "elevator or rudder pulse" to fluctuate"be affected,,move jitter" when moving throttle stick on radios?

Thanks for your help so far.

Interesting posts.
I don't have an Eclipse7, but I am a radio tech.
My thoughts.

Sounds like it could be either way off frequency (the TX) or that the TX module is crashing out the units CPU and causing it to reset or lock up. There may be two issues here, clouding the ability to find the cause. Having two simulataneous faults makes life hell for diagnosis. The posts seem suspicously like that to me.

If it's the TX crashing itself with RF power an easy test is to move the antenna away from the TX unit by some meters with some 50 ohm coax. I don't know the E7 radio so I don't know if you have antenna sockets on them ?

I had similar issues with a micro proccessor project I made that involved UHF CB radios. I had to remote mount the antenna to fix it temporarily.

I think that the sooner someone gets one of these radios and an effected RX or two to a well equiped radio tech with a frequency counter and spectrum analyser, the sooner the truth will be revealed.
Martin

Thanks Sneezy, for your thoughts.

Not sure where to send mine to get checked.

Will keep you all posted with progress.

Thanks.

Sorry for a hijack, but its the only thread i could find deatails on 36/35Mhz.....

... I'm just wondering, Can 36Mhz Tx control a 35Mhz FM Rx?

If so, how is it done, just match crystals? Or do i need to modify something?

The reason i ask is because i want to control a 35Mhz XRB Lama SR with my 36Mhz JR 9X Tx.... What do you guys reckon the chances of getting that to work are?

or shoudl i jsut get the version WITH its own transmitter?

thanks guys

Loz