Transmitter and Receiver blues

[hampboats]

Is there anyone who knows of a good tutorial on understanding all the different types of radios and what works with what. Dual conversion, AM, FM, negative shift, narrow band, some brands of radios don't work with some servos, it getting to the point that I spent hours searching for what crystal works with what receiver and what receiver doesn't work with which radio. And, what about the Seeker, is it the final answer (if you can get one)
Help!!!!

Please Keep it simple.

[wayne frey]

Good point.
I would like

Good point.
I would like to see an in-depth discussion of the various advantages and disadvantages of all of the transmitters avalable to us.
For example, I like the looks of the Multiplex radios. But most are "synthesized", or without crystals nowdays. I have often wondered if they could be reset somehow to surface frequencys. Multiplex says no,but anything is possible, I am guessing.
My thought is a radio with the twin slide controls for my one twin screw boat, and more than enough channels to handle the Oscar, a future build, which I will need a 10 channel, maybe 12.
With the one radio programmable for all the boats, I should be set. I am open to options for peoples thoughts on radios, and it would be a good discussion.
The future need for more channels, by the way, is why I have my custom twin stick Multiplex 7 channel posted for sale

[dean]

I hate that every one

I hate that every one has dreamed up their own standards. Futaba decided on negative shift but JR went with positive. Futaba servos roatate one way, Hitec go the other way. I use to try to keep up with it but gave up, I now just get Futaba compatible devices.

I went through a bunch of radios before going with the Robbe line (Made by Futaba). They offer the F-14 in US frequencys now (use to be only european). The F-14 is a good radio that can be expanded. I have one dedicated to a surface boat with a ton of features. The problem with this radio is that it's not a computer radio so it's difficult to set up for more then one boat.


The most useful radio I have is my FC-16. It's similar to the F-14 but is a computer radio with multiple models memory. The big problem with this one is you can't buy it on US frequencies. I ended up converting this one to 75 mhz and adding the duel throttle control. I use it for 12 different boats so far.



As for receivers, If I only need 5 channels I buy the Novak XXtra units which works with both positive and negative shift radios otherwise I just get a Futaba.

[petn7]

It's not quite what you're

It's not quite what you're asking for, but:

http://www.rcgroups.com/radios-135/

It's a message board, but they can answer all your questions (if you have specific ones), for the most part.

[hampboats]

Huh???? What was the question again?

This was taken from the RC universe board.
They don't even seem to agree or understand fully. Can someone else review this and give me an opinion. Or better yet a spread sheet or flow chart. javascript:emoticon(':shock:')

http://www.rcuniverse.com/forum/m_1816309/tm.htm

The shift is the way the FM signal is modulated. Because the modulated signal is different, you cannot use a negative shift transmitter with a positive shift receiver or visa versa. Hitec and Sanwa transmitters are shift selectable and can be changed to match another brand of receiver in use whilst JR 72 Mhz & 75 Mhz TX are fixed positive shift and Futaba are negative shift. Hitec used to produce two types of receivers marked for Hitec/Futaba use with negaitive shift and the other marked positive shift for use with JR & Airtronics 72 & 75 Mhz TX. New Hitec 72 & 75 MHz RX now have auto shift and automatically change shift to match the Transmitter (caution = Golden rule applies now more than ever with auto shift, PLL and IPD receivers = TX On First - TX Off Last or the receiver may not lock on to your TX - picking up some other close to frequency signal instead). JR also now produce some receivers with either positive shift as used with 72 MHz for JR and Sanwa (aka Airtronics) and Negative shift for use by Futaba and Hitec on 72 Mhz. and 75 Mhz.

[chips]

The simple answer to you

The simple answer to you question is to buy all of your radios and receivers from the same manufacturer - that way you can insure your receiver really does work with your transmitter.

Take a look at the Sombra Labs line of receivers. I use them in my subs with a Futaba 6EXAS transmitter on 50 MHz (I have a Ham radio license), and have had no problems with them. They're synthesized receivers so you don't need a crystal.

Narrow band should be the only systems available and used in the US now. The older wide band equipment was made illegal by the FCC in 1998. Prior to the mid 1980's we didn't have as many radio frequencies available to us, and those we did have were wide band systems. The AMA took the lead, and got the other rc model groups (IMPBA, NAMBA, ROAR, etc) to agree to petition the FCC for a new freq plan - which gave us the 30 chanels on 75 MHz. The new "1991 compliant" systems started selling in the mid to late 1980's. The 1991 compliant systems are narrow band units with 20 KHz spacing.

[wayne frey]

I would have thought this

I would have thought this thread would be more lively....
So, can a computer radio for air freqs be converted to surface?? If so, that would open up options big time. I saw above where someone else had done it. It would be interesting to see how.
While our choices are pretty good, the higher end 9 channel and above market, understandably from the manufacturer's stand point, is focused on the R/C aircraft market.
Any thoughts about converting a computer radio to surface? I think it can be done, but that is definately out of my area of how to do's.

[petn7]

I would have thought this

I would have thought this thread would be more lively....
So, can a computer radio for air freqs be converted to surface?? If so, that would open up options big time. I saw above where someone else had done it. It would be interesting to see how.
While our choices are pretty good, the higher end 9 channel and above market, understandably from the manufacturer's stand point, is focused on the R/C aircraft market.
Any thoughts about converting a computer radio to surface? I think it can be done, but that is definately out of my area of how to do's.

At least with Futaba, their higher end computer radios designed for helicopters and airplanes can be converted for surface use by just swapping out the frequency module. I use an eight channel 8UHFS on 75 MHz after I bought a separate surface frequency module.

[chips]

So, can a computer radio

So, can a computer radio for air freqs be converted to surface?? If so, that would open up options big time. I saw above where someone else had done it. It would be interesting to see how.
Any thoughts about converting a computer radio to surface? I think it can be done, but that is definately out of my area of how to do's.

Send the radio to the manufacturer's authorized service center to get it converted from 72 to 75 MHz. Most of the service centers have a fee for the change.
Airtronics doesn't provide a price list.
Futaba charges $20 per transmitter or receiver for changing the freq.
Hitec charges $14 to change the transmitter and receiver frequency.
JR says their minimum labor charge is $7.50

[KevinMC]

Further to PETN7's response, if

Further to PETN7's response, if you can still get Hitec's synthesized Spectra 75 you'll find it's exactly the same size as Futaba's frequency modules... I've talked to many people who've had great success with this combination, and I can speak to how well it works as well.

[Guest]

I have been very hapy

I have been very hapy with JR 10 ch radios for years now as well as Futabas,those 2 have never let me down and the computerized system makes setting up and operating many subs a snap and would have been impossible to have all of those neat extras and advances possible .

I cant see to this day why anyone would buy a radio that is not computerized its like running in the stoneage.Why go through all that hassle of setup only to do it again on the next model when its time to go sail!.
JRs and Futabas are cheap now on the web Ebay or RC Universe are great sources.Extra 10 chanel PCM recievers that cost over 200.00$ back in there day are selling for 30 bucks and are rock solid.
I have also Futabas 9CAP robotic radio on 75 mgz PCM that has 32 chanels!
Great for a battle ship or robot but I think the reciever brain is too large for subs so I just use the supplied 8ch 75 mgz PCM reciever.I might sell it only for the above reason but what a radio!
These radios are simply ausome in every way built to last and are state of the art,servos interchange with a slight plug mod.In one sub the front planes are ailerons and dive planes all in one by a simple program.

I had a F-14 and got rid of it ,not computerized,and got a JR 10X for much less!
As for the dual sticks I just use the side sliders on the upper corners left and right midle stop ,up forward down reverse.Not only that but to aid in the turning of my XXI a large boat with a small rudder the screws are programed to increase thrust respectivly on rudder input and is variable ,more turn more thrust and that way I dont have to adjust the thrust at every turn Nice!
Or I also have made a single stick into 2 side by side as the F-14 yaers ago.
No special /very expensive modules to buy for every sub and what a loss if floded, no way! All the programing stays in the tranmitter and can be in some ceses be tranfered to your buddy via the internet.
You will love a computer radio!

[fgroza]

I have a JR 8103

I have a JR 8103 that I fly with on 72mhz. By replacing the module in the back of the transmitter, I can go to 75mhz, I have a ch80 module that works with Polks seeker receivers or Sombra labs units. Horizon said that the 75 mhz modules are still available. Will fit 8,9,10 ch transmitters.
Frank

[n1lul]

What about 2.4 Ghz?

New guy here.

The spread spectrum 2.4 Ghz radios have taken over the car world and are quickly taking over airplanes. Has anyone experimented with this technology in subs yet? There are some excellent 2.4 radios and conversion modules out there.

Ray

[subdude]

Hi Ray,

The 2.4g radio systems

Hi Ray,

The 2.4g radio systems don't penetrate water well, if at all. Transmitting thru water requires long pulses. There's a real scare among the sub community that if everything goes to 2.4g, we're in deep trouble (pun intended)

Jim

[bigdave]

Wayne,
I think you are

Wayne,
I think you are confusing computer radio with a synth radio. You can buy computer radios on 75 or have 72 MHZ computer radios converted to 75MHZ. But the only 75 MHZ computer radio with synth I know of is the Polks. Although you can buy a synth unit from Hitec that will fit the Futaba CAP-9. That is why you need one of the non-synth Multiplex radios to have it converted to 75MHZ.
I don't own stock in Multiplex but my EVO is the best radio I have ever owned. And I have owned many radios in my 45 years in R/C. BD.