SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jul 16, 2011, 07:46 PM
Registered User
wjroper's Avatar
United States, CO, Thornton
Joined Jul 2011
19 Posts
Question
JR PCM-9 NET-J129F Tx Compatible with JR NER-236XZ Rx

I'm lost - Is the JR NER-236XZ a PCM-X receiver and thus not compatible with a Plain JR PCM-9 Tx? And, can someone explain to me the difference between the JR PCM 'X' Rx and the JR PCM 'S' Rx.

The lack of reference data from JR is a major negative in equipment selection.
wjroper is offline Find More Posts by wjroper
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 16, 2011, 09:05 PM
Registered User
Joined Aug 2002
5,811 Posts
Old & New type PCM systems

Quote:
Originally Posted by wjroper View Post
I'm lost - Is the JR NER-236XZ a PCM-X receiver and thus not compatible with a Plain JR PCM-9 Tx? And, can someone explain to me the difference between the JR PCM 'X' Rx and the JR PCM 'S' Rx.
The lack of reference data from JR is a major negative in equipment selection.
JR/Graupner have had Two PCM systems on the market.
Original
Z-PCM (512) uses interlacing, e.g. every 21,77 ms channels 1 or 5, to 2 or 6, 3 or 7 and 4 or 8 gesendet, like 50 Hz half images on a TV screen that together give a 25 Hz full image. This would mean a frame rate of 2 complete frames for channel 1, or 43.5 ms. But if the data for channel 5 has not changed and the data for channel 1 is new, channel 1 will be sent in stead of channel 5, twice as fast or every 21,77 ms. Information about the channels that are actually transmitted in the received frame is of course also contained in the data. Accuracy is nine bits. A bit error means no data for 21.77 ms . Putting the "fast" channels in the 1 to 4 block and the slower ones in the 5-8 block allows optimal use of the command chain.
New (circa 2000)
S-PCM (1024) from JR/Graupner is a development of the previous system. To reduce downtime, smaller blocks of 10.65 ms are constructed. Four of these make up a complete 44 ms transmission message, providing data for each servo twice (21.30 ms frame). Accuracy is ten bits.

Extremely few JR receivers are Dual conversion.
JR have stuck with their patented unique signal processing system called ABC&W. ABC&W stands for Automatic Blocking Circuit with Window. ABC&W systems are said to have distinct advantages over single or dual conversion receivers. ABC&W systems create a very small electronic window that looks for the specific frequency that the receivers crystal is on. Any signal that is off spec for this window is rejected, and then the allowed signal is cleaned up, amplified, and re-routed through the window many, many times till all that is left is the pure signal on the channel that is coming from your transmitter and then sent on to the servos. This is said to take place without any noticeable delay of response from your stick movement to the servo. However, in recent years, a few USA club flying fields banned the use of the ABC&W RX due to unexplained "hits" and permit Dual conversion RX
only.

(FWIW - Futaba also has two PCM systems (512 & 1024) as does Hitec with PCM & the fastest of all which is QPCM)

Alan T.
Alan's Hobby, Model & RC FAQ Web Links
A.T. is offline Find More Posts by A.T.
Reply With Quote
Old Jul 17, 2011, 04:20 AM
Registered User
United Kingdom, Slough
Joined Aug 2003
1,962 Posts
The 236XZ is a Z class receiver using ZPCM, you need to turn the modulation of the PCM9 to match it.

But thinking about it, the PCM 9 doesnt have the option to switch modulation settings. What other receivers have you tried ?
theaton56 is offline Find More Posts by theaton56
Last edited by theaton56; Jul 17, 2011 at 04:30 AM.
Reply With Quote
Old Jul 17, 2011, 07:06 AM
Registered User
wjroper's Avatar
United States, CO, Thornton
Joined Jul 2011
19 Posts
What a great resource you guys are! Thanks.

Follow up: I've got a JR PCM-9 which looks great, works perfectly and is on the Ham Radio Band. I was hoping to use these small light NER-236XZ receivers with that Tx. The other Rx's I have - which work perfectly - are too large.

So, my choices: Find a used JR TX on Ham band that uses PCM-X; alter the NER-236XZ Rx's to accept straight PCM; or put the PCM-9 in moth balls and start over.
wjroper is offline Find More Posts by wjroper
Reply With Quote
Old Jul 18, 2011, 02:49 PM
Registered User
United Kingdom, Slough
Joined Aug 2003
1,962 Posts
You would need to be looking at a 642, 652, 662, X347, X388S, 8103 (or 8103ADT) to get Z class modulation. HH had their XP9303's imported with Z class disabled.
theaton56 is offline Find More Posts by theaton56
Reply With Quote
Old Sep 26, 2013, 09:01 AM
Registered User
Joined Oct 2007
21 Posts
JR NER 236 receiver

I've got a JR 652 transmitter and two NER 236 XZ recievers for sale if anyone is interested.

Thanks
pacoflyer is offline Find More Posts by pacoflyer
Reply With Quote
Old Sep 26, 2013, 10:13 AM
Registered User
yorkiepap's Avatar
SW PA
Joined Aug 2010
461 Posts
I have (2) absolutely mint JR PCM9's....one is a Net-J129F airplane Tx w/2 J229P 9ch Rx's & the other is the rare Net-129HG Air/Heli Tx w/1 NER-910XZ 9ch Rx. They are beautiful units & one day I'm gonna try them out on a couple foamy high-wing trainers. Oh, BTW, my JR10X also has SPCM & ZPCM along with PPM for 2.4. Here's some pics....

Denny
yorkiepap is offline Find More Posts by yorkiepap
Last edited by yorkiepap; Sep 26, 2013 at 10:18 AM.
Reply With Quote
Old Sep 28, 2013, 09:46 AM
Registered User
BELLINGHAM,WASHINGTON
Joined Jan 2008
13 Posts
Quote:
Originally Posted by yorkiepap View Post
I have (2) absolutely mint JR PCM9's....one is a Net-J129F airplane Tx w/2 J229P 9ch Rx's & the other is the rare Net-129HG Air/Heli Tx w/1 NER-910XZ 9ch Rx. They are beautiful units & one day I'm gonna try them out on a couple foamy high-wing trainers. Oh, BTW, my JR10X also has SPCM & ZPCM along with PPM for 2.4. Here's some pics....

Denny
I too have (2) PCM 9's Air version. They still work very well. I believe they are the early version (512 series). They are on Ham band which I flew for years on. But I want to convert to 72 mhz. So, I would need a module and receivers to match. What would I need as in model numbers, etc. to convert over.
I've been a JR person since Kraft went away. Thanks for any assistance in this area.
Mike
RACE 66 is online now Find More Posts by RACE 66
Reply With Quote
Old Sep 28, 2013, 08:04 PM
Registered User
yorkiepap's Avatar
SW PA
Joined Aug 2010
461 Posts
Hey Mike,
You can use any of the JR Net-J72P modules....Tx crystals are still available for most all the 72Mhz ch's.. The bugger is finding the J229P Rx's. The PCM9 owners manual doesn't specify any other Rx. You could post in the Radio Classified Section a "Wanted JR Net-J229P Rx" & you may find someone who would part with one or perhaps more. These radios are a joy to "feel"....solid like a bank vault. Here's a pic of one of my modules/Rx......

Denny
yorkiepap is offline Find More Posts by yorkiepap
Reply With Quote
Old Oct 01, 2013, 07:52 AM
Registered User
BELLINGHAM,WASHINGTON
Joined Jan 2008
13 Posts
Quote:
Originally Posted by yorkiepap View Post
Hey Mike,
You can use any of the JR Net-J72P modules....Tx crystals are still available for most all the 72Mhz ch's.. The bugger is finding the J229P Rx's. The PCM9 owners manual doesn't specify any other Rx. You could post in the Radio Classified Section a "Wanted JR Net-J229P Rx" & you may find someone who would part with one or perhaps more. These radios are a joy to "feel"....solid like a bank vault. Here's a pic of one of my modules/Rx......

Denny
Fair enough ! Thanks Denny.

Mike
RACE 66 is online now Find More Posts by RACE 66
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! Crystal for JR Receiver NER-236XZ wjroper Radios 3 Jul 17, 2011 04:22 AM
For Sale JR PCM S NER-649S 9 channel rx with channel 22 crystal PRICE DROP!!!!!!!!!!!!!!!!! Ben-Rod Aircraft - General - Radio Equipment (FS/W) 2 Feb 27, 2010 07:01 AM
JR 6 channel zpcm rx NER-236XZ fs David Hogue Aircraft - General - Radio Equipment (FS/W) 8 Feb 02, 2005 11:03 AM