RedGN

I have 5 parkzone planes, two of them i swapped out all the electronics and put in spektrum receiver, hitec servos, Brushless motor/ESC and so on. The other three are stock however i want those three on the same frequency so i only need one transmitter at the park. Does anyone know where i can get receiver crystals for these? Two of those three are zx10 system and the other is normal, will it still work with one transmitter?
thanks

reaperofsoulz

im fairly new to this myself but also I have 4 parkzone planes. Even though 2 of them were the same channel (crystal) the one with the ZX-10 system transmitter didnt work right on the same channel plane that wasnt zx-10. HOWEVER this could be because of the V-tail and T-tail configuration setting on the zx-10 radio because i was trying the spitfire control with a stryker
good luck

BubbleGum

Parkzone uses standard crystals. Your local hobby store should carry them. Also, tx and rx use the same crystal, ie. one size fits all.

~Bub

johnpcunningham

Unfortunately that is not correct.

If you wish to use one transmitter with all planes, you can change out the RX crystals. These are on the 27MHz AM band and you can buy them based on the channels 1 through 6, as alloctated by the FCC.
You usually purchase them in pairs at your local hobbyshop (TX & RX) or you can just order the RX online, like towerhobbies for around $4 per crystal

The original parkzone/hobbyzone Transmitters (non ZX-10) does NOT use a standard 27 MHz crystal for transmission. They do on theRX side It uses a different crystal for the local IF and it seems to run it through an up-converter.
I have not taken apart the ZX-10 radio yet so I'm not sure if they use standard 27MHz TX crystals - my hunch is that the still do not - like the original transmitters.

So, to answer your question, change out the RX crystal to match your transmitter.

JC

RedGN

Thanks for all the advise, however i already know that i need to change the crystal. What i am looking for is a place that sells receiver crystals. Tower Hobbies does not sell them (looking through thier inventory). I checked everywhere on the internet and couldnot find them. (ch1-ch6) I don't want to spend $30 for a new receiver.

Thanks again

BubbleGum

OK, Thanks John. I am only 1 year into this hobby. So I guess parkzones used to run 27 instead of 72 MHz (?). Anyway, the PZ receiver that came with my Typhoon worked just fine in my pgp Stryker. Now I have a JR tx/rx and the PZ crystals work on that radio and the 'standard' 72MHz crystals from my LHS work fine with the PZ radio.

If I could trouble you with a question... The crystals I run don't care if the are in the tx or rx. Interchangeable. There are receiver only crystals?

~Bub

johnpcunningham

RedGN

I went to tower hobbies and found them: http://www3.towerhobbies.com/cgi-bin...I=LXBFK2**&P=7

I simply searched on 27mhz & RX. When you order, you need to specify the channel.

BubbleGum,

The TX and RX or not the same crystal. For the 27MHz standard band, they are offset by 455KHz. If I remember correctly, the TX frequency's is 455khz less than the RX crystal frequency.
This is standard RF stuff for IF frequency conversion. The 455KHz is the bandwidth of the received signal and all of the tuning on the RX filters to 455Khz wide for the narrow band filter.
You will notice when you look online that for any standard frequencies (27, 72, or 75 mhz), the crystals are generally sold in pairs. This is why.

JC

RedGN

John,

I did not know that the futaba 27mhz crystal worked on parkzone products. I was searching for parkzone specifically.

You are sure that this crystal will work with parkzone stock receiver and transmitter?

If so then, Thanks alot.

johnpcunningham

YEP - IT WILL WORK!

The FCC allows the RC community a specific set of frequencies to operate on. in the FM band, these are usually 27, 72, and 75 MHz. Your 27MHz band operates on channel 1 through 6. Although these are typically specific frequency pairs (TX & RX),they are mostly sold by the base frequency (27MHz) and channel number. The crystals that you buy are based upon these specific frequencies and will work on your planes.

The original crystals may be soldered to your board or may be on little plastic 'sockets" where the crystals can be easily swapped. The crystals that you purchase will have two "thicker" shafts. If your crystals are soldered on your board, they will probably have "thinner" shafts. You will need to drill the holes on your RX boards just a little - around 1/16" or less to install the newer crystal - that is if it does not have a socket. If there is a socket then it is an easy swap. You can always put the original bck in, just use mre solder when you re-install.

I've done this a bunch of times and mostly with success. Since all crystals and RF boards have variations, every once in a while, I've noticed that changing out a crystal will cause the plane to operate in short range only. Most of the time, everything works fine.

Change out your crystal and do a range test prior to a full launch. If your range test works then you are good to go. If not, try a different crystal of the same channel. This is easier then trying to tune your board's RF inductors without the proper equipment to measure.

-------
Some of the Parkzone stuff, like the Stryker-C, runs on a 72MHz radio. I have not dug into those to see if the TX & RX crystals are the same. But I do know the Hobbyzone/Parkzone 27MHz band does. If you go online and look for 72MHz, see if they are sold in pairs of TX & RX. If so, then they are probably on different offset frequencies.

JC

RedGN

John you have been a great help. I hope others ( including myself) can learn from guys like you and pass it on to others that need it

Thanks again.

Aientonni

My Parkzone 3 channel transmitter on channel 6 ( FM 27.255 mhz) purchased with my PD-51 recently came to a premature end under the rear tire of my van. (Don't ask!) I have a Futaba 4 channel transmitter on channel 34 with the matching RX crystal. I was wondering if it I could swap the current crystal on my plane's receiver to match my Futaba. Would it work? Has anyone tried. I'm curious because I'd rather not spend money on another transmitter. Thanks.

johnpcunningham

It wont work. Completely different frequency.

For those technically interested:

Your receiver on the Parkzone and Hobbyzone planes have a narrow-band filter. Think of your car radio; it receives all the stations but when you tune to to your station (103.5) it filters out all of the others. The radio bandwidth is +/- 200Khz. That is why all of the stations on yor radio end in an odd number - the station is allowed to drift a little left or right of 103.5 and your radio will track it internally (PLL, RF, lots of math, etc).

Your hobbyzone plane uses the crystal in the same way and the onboard inductors, caps, and 455KHz filter rip out the RF component and provide the data signals to the on-board MCU. Generally you can change crystals on these because the tuning is so close (Ch1 to CH6). but you can't make a big jump to 34 MHz or 72 MHz because the tuning circuits on the RX won't work correctly. It is like asking your car radio to tune to a HAM radio band, it just is not made to filter out the unwwanted frequencies.

Those cans you see on the RX boards - the ones that look like they have wax in them. Those are called tuning inductors and this is what tuned the circuits (antenna) to the gain stage of the amplifier to provide maximum amplitude. They are factory adjusted and then wax is put in them to keep the screw from moving again. I do no suggest messing with them because without RF test equipment, you may never get it back to where it needs to be.

Hope this helps,

JC