Hi there all,

Here I'm again with new questions which just popped up on my mind yesterday and Im thinking about it whether is it possible or not?

Question is JR's Tx model XP7202 is fully synthesized crystal free. The Rx comes with it is R790 Scan select PCM. PCM I understand is Pulse Code Modulation what are S-PCM, and Z-PCM, second thing, if Im using XP7202 with Fully synthesized Rx naturally whatever the frequency is not being used can be selected and used, but if Im using another Rx with a crystal on it and it is FM like its 72.810, is it possible that Fully synthesized Tx may work with an Rx which has crystal on it and has frequency of 72.810, do we have to select on 72.810 frequency on our Tx and it would communicate with Rx with crystal and work, or fully synthesized Tx would always work with fully synthesized Rx not with those having crystals. Sorry if it seems an unusual question but I wanted to have clarification cos, my second radio is JR's XP7202, and I would need more planes with naturally more Rx with crystals.

Thanks in advance

Mody

Yes it does.

Thanks bigedmustafa

Mody

Glad to help! Feel free to asky any question that might pop up.

Good question, I've been thinking about getting that TX.

Thanks, Del

Thanks bigedmustafa & Del,

Well, at least it has cleared the clouds of doubts from our minds that synthesized Tx can work with crytalled Rx. One more thing SPCM or ZPCM are the versions of PCM?


Mody

I haven't owned a JR radio as of yet, but I can take an educated guess here. S-PCM and Z-PCM are probably different kinds of JR PCM modulation. One is likely the current type and the other is likely an older type that was included to be compatible with older PCM receivers.

Hopefully a JR owner or two can fill in some blanks here for us...

The only thing not mentioned in this thread is that you must be in the same band. If Airborne, 72 MHz range (there are also some HAM users that can use some frequencies in the 50 MHz band but I don't know if there are any synthesized dial-a-frequency in that band).

What that means is that if your receiver is airborne use, (72 MHz in the US, not sure what it is in Pakastan) then the transmitter must be in that band. We have channels 11 to 60 here in the US that operate in the 72 MHz band and radio's such as the Polk and JR are all compatible with receivers in that band. If your receiver is 36 MHz, for instance, you must have a transmitter that is capable of dialing up that frequency.

Sorry if this confuses you, but it's important to know if you are going to get a synthesized radio.

DS.

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Armody: I just re-read your post and edited mine accordingly: It appears that you understand this issue but I thought I would keep it here for anyone else that may have a question about that in their mind.

I'm not a JR guy either so if I wanted to know the difference between S-PCM and Z-PCM I would ask Danny in the JR Radio support forum.

http://www.rcuniverse.com/forum/forumid_116/tt.htm

ZPCM and SPCM are just two different types of PCM encoding. ZPCM is the older type, with 512 steps of resolution. SPCM is the newer type, with 1,024 steps of resolution. You set the transmitter to the type of PCM that your PCM receiver is designed for.

That's what you do IF you have a transmitter with selection capability.

Which, of course, this one has.

Well Thanks a lot all,

I have understood things pretty much, and Im sure that in order to get into the abyss of that, we need to turn the internet upside down.
In Pakistan, people use all kinds of frequency mostly I have seen 72, which I'm using it, and also 50 I've seen people using. There is only one particular flying club and it has one field and I don't fly there anymore, as its between a refinery. I have stopped flying there as its hazardous as well, but they observe all the flying safety measures, frequency board etc. I go to an open field where there is no interference and not a lot of flyers come. We 4 people used to go, now we 2 people go, and we know our frequencies, and it doesnt clash. What are steps of resolution? are they like further band or coding like computer that old programs used to be 32bits, now they are 64 bits?

Mody

If you are speakin of like how Futaba PCM has upgraded from 1024 to 2048 resolution then YES. It's like taking a pie and dividing it up into 2048 pieces and telling the waitress which one you want. Yeah, I know not much pie to eat.

JR is similar of course.