Ham Radio Operators - Converting a JR RF Module

[Miami Mike]

I was just informed by Horizon Hobby that 50 Mhz rf modules are no longer available for the JR XP8103, 9303, and other module-based JR radios. Therefore, there will very likely be a growing need now for a way to convert 72 Mhz modules to 50 Mhz. Any thoughts?

[Pinecone]

2.4 GHz. :)

[mtucker]

So does JR still make non-module 50mHz radios? I am guessing all their high-end radios are modular.

Matt

[Lakc]

Got any schematics?
Likely only have to change a few capacitors and one variable inductor in the input stage, but then again, nothing is that easy. :)
Jeff
AB8XE

[yctseng]

JR modules' PCB are all the same. From 27MHz to 72MHz, just some of the parts
and values are different. But why you want to use 50Mhz band ? That's for HAM
radio !

[Miami Mike]

But why you want to use 50Mhz band ? That's for HAM
radio !Because (1) I'm a ham radio operator, and (2) I have over $1000 worth of 50 Mhz R700 and R770 receivers installed in several model planes. I don't want to risk getting grounded if my only 50 Mhz module fails.

[village_idiot]

Can you clone that module? the value on the inductor and variable cap. are probably the hardest part. A spectrum analyser would be nice to make sure you don't have any out of band spurs.

[Discharger]

Because (1) I'm a ham radio operator,don't want to risk getting grounded if my only 50 Mhz module fails.

If it fails then you have the knowlege to fix it!
2.4G is looking very attractive but which system?

[mtucker]

I search Ebay every now and then for RC stuff on 50MHz. The Berg and FMA 50MHz receivers are pricey, but I sometimes find great deals on them on Ebay.

Matt

[Miami Mike]

That's good to know, but I don't need any more receivers. I need a JR 50 Mhz rf module and Ebay doesn't appear to list any. I checked.

[mtucker]

I see Futaba TX modules fairly often on Ebay. Keep checking back, there are bound to show up eventually.

Sounds like you could make some money converting 72MHz modules to 50MHz for JR users.

Matt

[Pinecone]

Just keep checking, 50MHz modules show up every so often, and check the classifieds here, I have seen them available.

N3MCJ :)

[barefootbass]

How about trying to fit Gordon Anderson's rf deck into a JR module case? It's fairly simple to build and you can get the kit for $50.

[Miami Mike]

Interesting! It looks like you could even produce something that's not commercially available (as far as I know) - a 6 meter module featuring switch-selectable frequency!

From http://www.mstar2k.com/MicroStar.htm: (http://www.mstar2k.com/MicroStar.htm)

The RF deck

The RF Deck is the device that is responsible for taking the modulation signal from the Encoder and generating the modulated RF. This RF Deck is designed around a National Semiconductor LMX2306 PLL. The details are pretty standard. The PLL must be programmed on power up and my Encoder provides this function. The RF Deck also allows you to use a small PIC microcontroller and a rotary switch to allow operation in a standalone mode.It turned out that I was able to order a new JR 9303 on 50 Mhz from Horizon Hobby, so when it gets here I'll have the backup rf module that I wanted. I'll probably swap out that module with an unneeded 72 Mhz module that I have and sell the radio new in the box.

[village_idiot]

As far as I know, you should be able to build the Gordon's module and it will work, but it looks like it works best when used in conjunction with one of his controler designs so that you can change the channel whenever you want. He also has a design for a receiver that you might want to look at.

[macquen]

I was just informed by Horizon Hobby that 50 Mhz rf modules are no longer available for the JR XP8103, 9303, and other module-based JR radios. Therefore, there will very likely be a growing need now for a way to convert 72 Mhz modules to 50 Mhz. Any thoughts?

I'm a ham - WB2TMR - I lost my call when I moved to NC in 1977 - regained it thru the vanity prgm. I have been flying on 6 meters since the bad old days of am superregen 52 MHz then, on or around 1958. Now all my JR eqpt. is on 53.4,2,3,6 FM since that band is still available for RC use, and is not required to be narrow band. I also fly home-brewed sub-micro 53.4 MHz superregen AM rcvrs for my micro 1/72" scale models using proportional actuators, and an Airtronics 6 meter AM xmiter.

73 - Steve - WB2TMR

[village_idiot]

Those are cool planes!

[dalbert02]

If it fails then you have the knowlege to fix it!


It seems to me that many people believe that once you get your license to experiment, you are suddenly an expert in building, fixing, and modifying all radio systems by all manufactureres. Although MiamiMike may be a very knowledgeable person, I don't think he would be asking his question if he already knew all the particulars.

Mike, I wish I could help you. If you find the solution(s), please share.

Just my $0.02

-dave

[Pinecone]

Keep looking here, eBay and other sites. I have turned down at least 3 50MHz modules in the last 6 - 8 months.

Try the heli forums (HeliFreak and RunRyder) as it seems I have seen more there.

[Miami Mike]

I have what I want now. I bought a new XP9303 with an R770 receiver from Horizon Hobby, both on my 50 Mhz channel, I kept the rf module and receiver, and I sold the radio for a fair price. The buyer will have the option of buying a synthesized 72 Mhz module for $99 or the 2.4 Ghz system for $299.

Although things worked out okay for me, my first post still stands. Horizon Hobby no longer offers 50 Mhz modules separately and I wouldn't be surprised if they were to soon drop 50 Mhz gear entirely. 50 Mhz receivers are still available from other sources, but if someone was to work out the procedure to convert JR modules, his work would probably be appreciated widely among ham operators who fly r/c. (And there are many of us. The two hobbies seem to go hand-in-hand.)

[ZAGNUT]

try contacting this fellow: http://www.qsl.net/k5bcq/MS2K/MS2K.html

he loves to tinker with these sorts of things and your challenge may be just up his alley.




dave