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RDS On Any Transmitter (No Soldering)


Dinosang
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I have been testing RDS data being sent using just software (Airomate) with LOR2. I have had no issues running both programs at the same time. Since LOR does not output RDS Info to a text file at this time I have had to manually update the text file as a show is playing to mimic an update from the LOR software. It has been working with no problems. My friends are amazed to see the song title and any message I choose to send on the radio as the music is playing. You must have a sound card that supports 192khz audio for it to work. I have managed to have this setup working with just the one sound card! So no loop through problems!

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Richard Hamilton

Out of curiosity, what kind of transmitter are you using?

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Richard Hamilton

By the way dino...

I'm surprised you even got that software to work. You must know something I don't.
I remember trying the Airomate software about 2 months ago because I thought it was a novel idea to generating an RDS signal with just software.

However I was frustrated with it right off the bat. The "Nag popups" were really annoying in the demo. They should have done that better. There is no user manual or help file for it and the interface was confusing. I never got it to work on two different computers even though they claimed that the sounds cards were supported.

I think that software needs a LOT of work to make it useful. I'm glad to hear that you succeeded in getting it to work. I wish there were something similar out there. I have RDS going via another approach but not happy with the implementation.

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Thats pretty cool.

I think the soundcard requirement is failry restrictive, as most soundcards are not 192k sampling. And the price of the airomate on top of it as well. Its probably a lot cheaper to use a dedicate hardware rds encoder like the one rlilly used on his EDM.

This same thing was done over on the EDM yahoo group with an EDM LED. And more recently, was done with a simple external RDS hardware encoder into the EDM LCD. I haven't heard in either case if it definitively works well.

The RDS can really lower the sound quality or at least adds noise ... so be careful.

Let us know how it works for you.

I love the idea of writing text to a file with a scheduler that simulates the LOR doing the same ... very ingenious! I guess its just a matter of timing ...

That would be a nice piece of freeware to write ... a program that allows you specify your show lms files (in order) and then sends rds text to a file at the correct times.

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Richard Hamilton

taybrynn wrote:

I think the soundcard requirement is failry restrictive, as most soundcards are not 192k sampling. And the price of the airomate on top of it as well. Its probably a lot cheaper to use a dedicate hardware rds encoder like the one rlilly used on his EDM.

Spot On! I agree. Although the software approaches are interesting, I don't think it is worth the hassle of setting it up, worrying about software failures or processing issues. I guess this is why I use the hardware encoders... less to worry about.
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Richard Hamilton wrote:

By the way dino...

I'm surprised you even got that software to work. You must know something I don't.
I remember trying the Airomate software about 2 months ago because I thought it was a novel idea to generating an RDS signal with just software.

However I was frustrated with it right off the bat. The "Nag popups" were really annoying in the demo. They should have done that better. There is no user manual or help file for it and the interface was confusing. I never got it to work on two different computers even though they claimed that the sounds cards were supported.

I think that software needs a LOT of work to make it useful. I'm glad to hear that you succeeded in getting it to work. I wish there were something similar out there. I have RDS going via another approach but not happy with the implementation.


Works great I have a registered version I am not sure about the demo. Try selecting the same imput and output channels on airomate you will not see the vu meters this way but there will be no delay on the output as the audio has to go through Airomate. Select NorthAmerican RDS and do not turn on sync. Also make sure you set your soundcard to 192khz manually also I believe your soundcard has to be able to record at 192khz ( not %100 on this). If you still have a lot of problems maybe I can email my config file it may be something you missed in your setup. I assure you it works better than I expected it to work for a piece of software and a sound card. My Radio station shows up as XMAS 92.7 (lol) and anything I put in the text file and I have the program poling the file every 3 seconds so the update is fast pefect for a light show. My trans mitter is nothing fancy got it of ebay from china but works great just has a little higher output than I think we are suppose to have but I am on a totally clear channel.

PS: Make sure you out from your soundcard is not set to high as this will distort the RDS signal as well you can also control the RDS output from Airomate.
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I decided to look into some of the features from there website and it appears there are some functions that do not work in Demo mode. Here is a list of the RDS functions and what does not work with the demo.

RDS options:


  • Traffic programme (TP)
  • Traffic announce (TA)
  • Music/Speech
  • Clock-time and date
  • Programme Type (PTY)
  • Programme Type Name (PTYN)
  • Programme Item Number (PIN)
  • Programme Identification (PI) (Not available in the demo version)
  • Extended Country Code (ECC) (Not available in the demo version)
  • Language Identification (Not available in the demo version)
  • Decoder Identification (DI)
  • Dynamic Programme service name (PS) (512 messages in registered version, only 2 in demo version)
  • Dynamic Programme service name from file input (Not available in the demo version)
  • RadioText (RT) (512 messages in registered version, only 2 in demo version)
  • Smart split; for splitting large PS or RT messages into smaller pieces.
  • Dynamic RadioText from file input (Not available in the demo version)
  • Inline commands for PS and RT message (Not available in the demo version)
  • 25 Alternative Frequencies method A (AF) (Not available in the demo version)
  • Unlimited Alternative Frequencies method B (AF) (Not available in the demo version)
  • Creating own data groups
  • RBDS support
  • Adjustable 57 kHz volume
  • Adjustable 57 kHz phase shift
  • Adjustable 57 kHz frequency or automatic

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taybrynn wrote:

The RDS can really lower the sound quality or at least adds noise ... so be careful.

It's possible to add RDS without adding noise. I added RDS to my FM25B (read this), and yes, it does add some noise, although most (non-audiophile) people wouldn't notice it unless they turned their engine off and listened carefully between songs.

...but then I did an RDS modification for an FM100B (read this). I improved my design, and ended up with no detectable noise. So it is possible to do RDS while keeping the sound quality, if it's done right.

I believe the secrets are (warning: technical information below):
  1. If you are transmitting in stereo, then you must use an RDS encoder that synchs with the stereo pilot signal, like the Pira32. You cannot use one with a free running carrier, like the MiniRDS encoder.
  2. When injecting the signal directly to the VCO, which you'll have to do with most low-cost transmitters, like the Ramsey or EDM models that use the BH1415 chip, you need to keep the RDS signal level low. This means you have to scale down the components recommended by Pira.CZ.
  3. Since you need to sync with the stereo pilot signal, the signal needs to get to the RDS encoder. Make sure there is no path for noise to go back into the transmitter over this path. I added an IC to my FM100B interface circuit to prevent this from happening.

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Richard Hamilton

Nice Info Steven!
I don't have any noise as I have more of a commercial grade system, but one of my friends with a modified Ramsey is getting noticeable RDS noise. We will check this out.

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I get no noticeable noise and degraded audio is also unnoticeable under normal circumstances. I can notice it when there is no audio being transmitted and there is complete silence but I actually get more noise from my transmitter by it self when there is just silence. Then again FM is not perfect!;) I think the subtle differences is worth the end result and as I said this is an option for people that do not want to hack their transmitter (no soldering). 192khz sound cards are a lot cheaper these days so the affordability is better. I was lucky I already had a very expensive rack mount sound card for my home audio recording PC and decided to give it a try with great success so I figure let others know it works.:D

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