Radios ?????
 

Questions about radios. I have inherited old Kraft and Futaba AM Radios. Too expensive to Gold Sticker these. I have bought 2 Spectrum DX 6's for my foamies. I have a couple of FM recevers on channel 46. My question is about single conversion and double conversion and what works with what? And can I use my DX6 for 40 to 60 size nitro planes with the small receiver that comes with it?

Please help!!!

RE: Radios ?????
 

Do not use the DX6 with nitro planes, get the DX7 for nitros.

If you have an FM (PPM) transmitter, you can use it with either single or dual conversion receivers, doesn't matter. Most single conversion FM receivers are limited range, though, for park flyer use only. The exception is JR, I believe all of their RXs are single conversion.

RE: Radios ?????
 

Thanks Paul,

What does the PPM mean and where do I find out if my transmitter is a PPM.

Denny

RE: Radios ?????
 

PPM means Pulse Position Modulation. Some also call it simply FM although AM sets also uses a form of PPM. PCM uses a form of coded FM. It gets confusing at first.[sm=bananahead.gif]

Tell us exactly what mfg and model of TX you have and we will help you figure it out.

RE: Radios ?????
 

depending on just how old your radios are it may not be worth it. however AM is still legal as long as the RX is dural conversion. I would not think AM Rx would be all that expensive. however, it may need some tuning adjustments which all radios need from time to time anyway.you paying for technician time more than anything.

RE: Radios ?????
 

It's NOT the RX that is the problem. The TX needs to narrow banded to avoid conflict with adjacent channels. If they are old enough they may not even be on legal channels on top of that. As he said in his original post, NOT worth the cost IMO.

The RX could be a pizza and nobody would care, it would be legal.:D Just not very effective.

RE: Radios ?????
 

So you got 2 DX6's as TXs for your entire fleet? or do you have an FM TX and want to drive the C46 RXs with that?

When any mfg says their RXs are single conversion that means they also sell double conversion. And they make the singles to sell for park flyers.

When a RX doesn't say it's double or single, that doesn't mean it's single. A lot of max strength RXs say nothing because the mfg doesn't use single/double conversion circuit design in his brand of RXs.

RE: Radios ?????
 

Single and dual conversion receivers can be both be excellent or both be poor in performance. Right now many JR's and Berg's are single conversion and better than a lot of dual conversion receivers. The quality of a receiver is in sensitivity ratings and in noise immunity which can be achieved by good design by either technique. In short, whether a receiver is dual conversion or single conversion has nothing to do with it's quality or performance.

RE: Radios ?????
 

Thanks guys, I'm leaning alot from this group.

Other than the two DX-6"s, I have two Futaba FG series Transmitters, One is a FM on channel 48 and the other is an AM on channel 46. I love these boxes and I have flown my Nextar on the AM one at my house (I live out in the middle of nowhere). I have not used the FM one yet but plan to fly my newly acquired Hanger 9 Mustang on it if it checks out OK, (it's got an old AMA sticker on the module).

How do I properly check it out, the receiver is the Futaba that came with the Nextar, (with the fancy flight training thing that I do not use).

Can I get or does anyone have a FP-TF-FM Futaba Module for my AM Transmitter to make it legal without spending a fortune?

Thanks,
Denny

RE: Radios ?????
 

You can't change your AM radio into FM by merely swapping the module. It's MUCH more complicated than that.

RE: Radios ?????
 

Contacting Radio Southand get a cost estimate would be your best bet.

http://www.radiosouthrc.com/

RE: Radios ?????
 

Already did contact radiosouth per someones suggestion before, great guy knows his sh@#!!!! He said buy the FM module for that transmitter (FP-TF-FM) and that would make it legal! He said try advertising on here RC Universe for one.

I don't really know the best way to go about advertising on this sight. I have been watching ebay for a couple months and no luck.

If I buy a receiver, what is a good relyable one that won't cost a bunch?

Denny

RE: Radios ?????
 

bruce88123

On the old FG series Transmitters you can literally change it from AM to FM by changing the module..
The entire TX section is in the module.

Think if it the same way you convert a 9C to 2.4ghz by changing a module.. same thing..

When Futaba did the gold sticker conversion on my FG's they put the gold sticker on the module..
I still have my old FG's and they work great but nobody at my club trusts them so I've only been using them in my gliders.

Check Ebay for the FM module.. Be sure not to get the 9C module (FP-TP-FM).. it won't fit.
You should be able to use any Futaba or HiTech PPM FM Rx.. High band with the Channel you have now..
If you get a module on Channel 11-35 you'll need a low band Rx

The 127DF is a good Rx..They were the current Rx until last year when the 168DF came out
They go on Ebay for $20-$30 plus shipping all the time. I'm sure there a few here on RCU too.

The Tower System 3000 S3k 7Ch RX is the same as a 127DF.. It's made by Futaba for Tower.

RE: Radios ?????
 

You will have to get up early to be more wrong than those statements.

djsdog; Forget the Kraft. If not already changed to narrow (20KHz) band, then the FCC grandfather time has run out.

>>>>
FYI: AMA Membership Manual

Transmitter requirements:

Narrowband transmitters are required for use with all
Channel number frequencies (CH 00-09 and 11-90).
Identification of narrowband transmitters is normally
accomplished by a sophisticated laboratory test. Narrowband
transmitters can also be identified as follows:
1. All PPM/FM and PCM/FM transmitters are narrowband. Only
AM transmitters sold as new, prior to March 1993, are suspect.
2. The manufacturer of a suspect AM transmitter can verify if it is
narrowband. If it is not, the manufacturer may offer to modify it to
narrowband specifications.
3. AM transmitters that were verified by test to be narrowband prior to
March 1998, are considered to be narrowband. A gold-color sticker,
marked “R/CMAAMA - RF CHECK” was formerly used to identify
these tested transmitters. However, it is no longer required to display
the R/CMAAMA Gold Sticker on these transmitters.
Any user modification of a Transmitter that might affect the
transmitted signal is prohibited by law and safety concerns. This includes
user replacement of frequency determining plug-in crystals and use of
plug-in frequency modules from another manufacturer. Transmitter
crystal replacement, with or without a change in frequency, requires
transmitter emission realignment by the manufacturer. Use of a frequency
determining module manufactured for use in another brand transmitter,
can result in off frequency and spurious emissions that cause interference
to other fliers.

Receiver requirements:

Receivers that meet the AMA Guidelines of reference 2 are
recommended for use at flying sites where several Channel number
frequencies are in simultaneous use. Receivers that do not meet the AMA
Guidelines (reference 2) may experience interference when operated at an
active flying site with several transmitters operating simultaneously.
<<<<<

It is not against FCC to use an old WIDE band receiver. However if you do, it will be subject to interference form another close channel transmitter or the pagers operating on the 10KHz off the rcvr. channel. It's YOUR airplane for one flight so have at it if you must. :eek:

edited because of screw-up on my part. Wide vice narrow.

RE: Radios ?????
 

Thanks Hossfly,

I think we may have gotten two different post confused. I gave up on the old Kraft Radios and wrote them off as a bad idea.

Your bold print statement above said that a module from one manufacturer placed into another is cause for
transmitter emission realignment by the manufacturer. I have a Futaba FG Transmitter with an AM module and if I replace the module with another Futaba FM Module designed for that Transmitter does it need realignment? If so then I'm confused again, then why did they have modules to begine with if you cannot change them.

Thanks

RE: Radios ?????
 

Nope read carefully..

It says modules from another manufacturer require realignment. We are just talking about replacing a Futaba FP-TF-AM with a Futaba FP-TF-FM..
That is allowed.

Now that does make me wonder how the 2.4g spektrum modules for JR and Futaba are allowed but thats getting off topic here.

RE: Radios ?????
 

The Spektrum modules for JR, Futaba, Airtronics, etc. were designed to be used in those radios, so I'm sure they got the appropriate FCC approval for them. If you use a module that was NOT designed for your radio, then you have a problem (like the using the Hitec synthesized module in a Futaba 9C).

RE: Radios ?????
 

Actually, a bunch of radios aren't "conversion" filtering at all.

Just because a radio doesn't say "double conversion" anywhere on it doesn't mean it is a single conversion. There are other filtering strategies than "coversion", single or double.

Truth is, you don't convert the mass of signals that comes down the RX antenna, you FILTER them to pick out the single one you want. The term conversion is an advertising one. Used by the people who figured if they took a "single conversion" that wasn't good enough for longrange work and ran the still junky signal back through the same process that hadn't cleaned it up good enough before, that it'd be something worth advertising.

RE: Radios ?????
 

"Conversion" refers to "down conversion" via mixing the received signal with a local oscillator.

All receivers down convert via mixing at least once, so they are at least single conversion.

"Single conversion" and "dual conversion" are NOT marketing terms, they are technical terms.

RE: Radios ?????
 

Don't mean to confuse things. My post was to "da rock" but then I brought you into it. I also goofed, so see edit in my post above.
"da rock" was so far off base that I just had to bring that to his attention, but did not care to write a book for his benefit.

The MODULES are the transmitting agent. The rest is mechanics to determine what and how transmission takes place. Now out there in the real world, people change transmitter crystals all the time regardless of the written words. Even now when freqs. are checked at some events, and especially on local fields, now and then a supposedly NB transmitter can be found blasting both sides of the spectrum's next channels.
Just proves that nothing is perfect. OTOH, in this day and age, actual equipment problems are very rare. Now the jug-heads using that equipment, well that is another story. ;)

As far as changing modules between suppliers, it is easy to legislate the most retrictive so that is what FCC usually does. Just say "NO". "Cliche:" Never ask anyone a question when that anyone is not qualified to say "Yes." :eek: OTOH, there is little chance of any major differences in the modules of anyone manufacturer.
Of course it is much easier and less expensive to have one or two small transmitting module/s to snap in place, than to put all that stuff in each transmitter itself.

RE: Radios ?????
 

I stand corrected.

I got an excuse, but truth is, it was my fault for posting what was a misunderstanding of what I was told by someone whom I knew to be much more schooled on this stuff. So screw the excuse.......

My fault. Sorry............

RE: Radios ?????
 

And first thing I see after walking away from this thread is the following.................

"....these receivers feature triple-tuned RF circuitry, a ceramic filter and TDSP (True Digital Signal Processing) to ensure the clearest, tightest reception."

Read it in an ad.
They don't say single conversion, or double conversion, but they'd be some number of conversions? And maybe the "triple-tuned" means they're triple conversion? But the signal is also ceramic filtered? But that's really ceramic converted?

RE: Radios ?????
 

Good Man, da Rock. Any man that can stand and say "My Fault" has to be a man of high moral character. IMO, you just climbed to the top of the ladder. [sm=thumbup.gif]

RE: Radios ?????
 

You guys are bringing tears to my eyes LOL!!!!!

Thanks for all your help guys, I now have a much better understanding of the RC radio (new and old). You both probably saved me a wrecked plane or two no kidding. But anyway I'm glad I asked. Now if I could just find a FM module for my FG series!!!!

Thanks again,
Denny

RE: Radios ?????
 

In all honest there are a lot of cheap complete systems on the market these days. Unless you are just determined to resurrect that particular set for some reason I'd get a new set.

4 channel http://www3.towerhobbies.com/cgi-bin...=LXEFJ4**&P=SM

6 channel http://www3.towerhobbies.com/cgi-bin...=LXRXF5**&P=SM

Fresh batteries, switches, servos, everything new and ready to go. And this isn't the only brand of course, check out Hitec and JR too.

RE: Radios ?????
 

AM is still legal. what you should do is block off the adjacent chanels to avoid the problem- read mr Stillmans RC REPORT COLUMN PLS!!! SOME OF THE kRAFT/PROLINE might be worth it depending on condition.