Feature Request for FM Transmitter Usage

[bhays]

I don't think this would be a very difficult thing for the software to do and it would save a tremendous amount of work for those of us who would like to transmit the name of the currently playing song via RDS.

RDS is the protocol that allows car radios with RDS support (most newer aftermarket and oem radios do) to display the station name, name of the song playing, etc. on your radio. Using an RDS encoder, you can transmit this along with your display music.

http://en.wikipedia.org/wiki/Radio_Data_System

The problem is that you need to send the information to the RDS encoder that you want to be transmitted. All rds encoders come with software to send info from a text file on the pc to the rds encoder. There are plugins for Winamp for this and most of the pc radio station software such as Zararadio, Jazler, etc. support this.

Basically, all we need is for LOR to update a text file in a directory with the name of the currently playing sequence. This could either come from the name of the sequence file, but the the better solution would be an extra field added to sequence information called 'rds text' or something similar. Thay way we could define the exact text we wanted transmitted. It would also be good to have a way to define a default string that would be sent if nothing was defined for a sequence. That way during intermissions, etc. it could just transmit a generic strings such as 'Welcome to Seymour Lights. Merry Christmas', etc.

I have talked with several folks on this board as well as the planet christmas forums who would like to add RDS and even some who have worked out Rube Goldberg solutions such as using one lor channel for each song and triggering an auxiliary program to update a text file.

This seems like an easy feature to add and those of us with RDS encoders would be eternally grateful.

[Sthunder69]

I second that request. My fiancee says my voiceovers are overly long because I give the names and artists of each song, but I feel that I should. This would be a great solution.
S

[TexasBullrider4]

i like that idea!!

[LightORamaDan]

We have a special version of LOR II that had very limited use this year and provided a mechanism to handle RDS. This enhancement was not released to the general public because a few more mods are required for general use. Changes will be included in LOR II to support RDS.

[Ponddude]

This is an awesome idea and I can't wait for this to come out!!

LOR II is so powerful it isn't even funny!

Greg

[Richard Hamilton]

Amen! I use RDS now and it is cumbersome to time the RDS announcements of song titles and other info independently of LOR.

I look forward to this feature.

[bhays]

Wow, ask and I shall receive... cool.

Which RDS encoder are most of you using?

[JonB256]

I looked around for RDS encoders. Saw a few kits that would require me to make my own circuit board (that's not happening) and some commercial units starting at $700 and way up (that's also not happening).

Perhaps Ramsey needs to make an RDS kit.

[Richard Hamilton]

Jeff Millard wrote:

So it's an add-on independant of the transmitter? It might be a good choice for a Co-op PCB order. I know a nice group of folks that might be interested in that. If anyone can provide some info on a PCB design... we might be able to make something happen.

Jeff

Hi Jeff,

Right, an RDS encoder is comletely separate from the transmitter in most all cases.. It just sends a digitally encoded signal that rides on the FM signal.

Some people have referred to them as "RDS Transmitters", they aren't transmitters, and the use of that term probably adds to the confusion. There are transmitters that already have RDS encoding built into them, so be careful to make the distinction.

I use this RDS encoder, but there are many good ones...
http://www.pira.cz/rds/

Currently, I use it with Zara Radio which supports RDS.

RDS is not cheap, but prices are coming down as more of then get sold.

[Richard Hamilton]

Oh Rats! I meant to post these other links and forgot. This happens when you get old :shock:

What is RDS...

http://us.kensington.com/html/11276.html

http://www.radiofuture.com/rdsgeneral.htm

[bhays]

Jeff Millard wrote:

Can the RDS encoder be added to an existing transmitter or do you need a transmitter capable of RDS?

The answer to your question is yes and no. The RDS encoder has to go between the stereo encoder and the transmitter (exciter). In the case of the Ramsey transmitters, the stereo encoder and transmitter are typically on the same circuit board and this can be tough unless they have an mpx out/in loop available.

If you have a separate stereo encoder and transmitter, you can simply plug the rds encoder in between.

I use a stereo encoder and transmitter from pcs electronics, specifically, the MAX PRO 4+ transmitter and the SE4000 DSP+ stereo encoder. I am going to add the RDS MAX 4000+ rds encoder for next season since LOR will support it.

I really recommend the pcs electronics stuff, it's affordable and very high quality!!

http://www.pcs-electronics.com/

[Richard Hamilton]

bhays wrote:

I use a stereo encoder and transmitter from pcs electronics, specifically, the MAX PRO 4+ transmitter and the SE4000 DSP+ stereo encoder. I am going to add the RDS MAX 4000+ rds encoder for next season since LOR will support it.

I really recommend the pcs electronics stuff, it's affordable and very high quality!!

http://www.pcs-electronics.com/

I've been looking at that stuff from pcs-electronics and the specifications on it looks really good. Had I not already bought the transmitter and encoder I am using now, I would have gone with pcs.

By the way, I am confused by your statement that the RDS must go after the stereo enocder. I am not currently doing it that way with my Ramsey transmitter, yet the RDS unit still works. Puzzled!

[bhays]

Richard Hamilton wrote:

By the way, I am confused by your statement that the RDS must go after the stereo enocder. I am not currently doing it that way with my Ramsey transmitter, yet the RDS unit still works. Puzzled!

I don't have much experience with the Ramsey stuff, how is yours hooked up. Is the rds encoder hooked up between the computer sound card and the transmitter?

[Richard Hamilton]

bhays wrote:

I don't have much experience with the Ramsey stuff, how is yours hooked up. Is the rds encoder hooked up between the computer sound card and the transmitter?

Yes, the encoder is hooked up between the computer and the transmitter.

[JerryAllen]

Richard Hamilton wrote:

bhays wrote:

I don't have much experience with the Ramsey stuff, how is yours hooked up. Is the rds encoder hooked up between the computer sound card and the transmitter?

Yes, the encoder is hooked up between the computer and the transmitter.

Richard,

From what I read in the manual the PIRA32 uses composite audio not stereo audio, how are you getting composite into and through the PIRA32 and then into stereo line level for the Ramsey FM100B?

Ref. http://www.pira.cz/rds/pira32.asp?p=PIRA32_Box

Bottom of the page.

[Jim_H]

I used the Pira MiniRDS (30 Euro) with one of the Chinese 1 Watt FM boards(attenuated down to the legal RF limit). Also modified the Ramsey FM10 from last year as a backup.

MiniRDS has a software application that works fine for putting song title and artist info on the FM, based on a text file that you generate.

Both worked fine for RDS.

The instructions of how to add the RDS signal to most of these transmitters is included in the MiniRDS documentation. You just have to solder in a resistor, capacitor and connector on top of the Varactor diode on the FM transmitter.

I used the Mini RDS not synched to the 19 KHz (freeruning) and found it still quite good. You just have to adjust the RDS level Pot on the MiniRDS - so that it does not mess up the Stereo (adjust it to minimum and then raise the level so that the RDS info shows up on the radio).

[Jim_H]

I used a 39K Ohm resistor to the Varactor(Varicap) and a 100 Pf ( marked 101) capacitor to ground, with a cap marked 103 in series with the RDS data. All parts from radio shack.

See attached file for pics.

Regards;

Jim


Attached files RDS FM Mod.zip

[JerryAllen]

:? The Ramsey has 2 Varactor diodes / varicaps. D1 and D2. The Vastelec uses the same BH1415 chip. D1 is frequency control, "If the desired frequency is less than the reference frequency, U2 sends negative going pulses out of pin 7. This in turn increases the voltage on the collector of Q4 (we will get back to this) causing an increase in the voltage across diode D1 (the main varactor diode in our oscillator circuit).", D2 "By adding an extra variable capacitor D2 (another varactor diode) along with C9 into the VCO circuitry, the composite signal is fed in to the VCO at a specific level after dividing it by R6 and R7.

D2 connects to composite audio, OSC and ground, D1 connects to OSC and ground only, which one?

Jerry
'


Attached files

[iresq]

Hey Jim, not to hijack but I just bought the same transitter. How did you attenuate the signal?

[Jim_H]

I would try the D2 varactor. The idea is to add the RDS 57 KHz carrier in with the Composite signal ( R,L and 38 KHz).

As a side note: I got tired of going outside to my truck to verify that I was sending the RDS info correctly. I bought a Chrysler Car radio off of Ebay ($12.00 because the CD 6 disk was bad) and used it in the house as a monitor. Radio was a PT Cruiser 2002 and up. No TheftLock or anything - just feed it 12 VDC.

Jim