RDS with a Ramsey FM100B

[Steven]

There has been some discussion on these boards about RDS and Light-O-Rama. If everything goes as promised, a version of S2 released well before Christmas will support RDS, which means that viewers of a light show with the right equipment may be able to see the names and artists of the songs being played on their RDS or RBDS-equiped car radios.

To that end, myself, Doug, and others plan to use RDS in our shows this year. This required the purchase of an RDS encoder and required our transmitters to be modified to connect with the encoder.

I have modified my FM25B, and I have just modified Doug's FM100B to connect to the Pira32 RDS encoder. You can read about the FM100B modification here.

[stachows]

Steven, thanks for all your research, and efforts. You make it look easy.....ALMOST!

I have soldered my LOR kits, and my FM25B kit and all of them work just fine...

But frankly, I am lost by reading your schematics:shock:, and explanation of how to modify the FM25B... I am sure that I should be able to handle soldering the Pira32 kit, and software is of no issue for me to work out, but....

If you could put together a very simple set of directions on how to modify the FM25B I would be eternally grateful. I understand if you would rather not, but I beg of man!!! Make it easy for us electrically challanged....:]



Thanks...Scott

[Steven]

Of course you're right. Instead of a "how to", I wrote my RDS story to describe the steps I took in my experiment, and my main target audience is other electronics experimenters, some of which I hoped would also have interest in adding RDS to their displays.

The basic problem is that I'm not sure enough about my design to give step-by-step instructions. I'd first like to have a "peer review" of some sort, where someone can tell me what modifications should be made to make the circuit more reliable.

But, if you want a step-by-step instruction with no guarantee, here it is:

Parts list:

• BNC to BNC cable, 15-36 inches (http://www.radioshack.com/product/index.jsp?productId=2103481, although if you can get one with a thinner, more flexible coax, that would be better. If you're up to it, you can buy your own cable and connectors and make your own. Or, you could get an RCA to RCA audio cable and two RCA to BNC adaptors.)
• 100kΩ resistor (http://www.radioshack.com/product/index.jsp?productId=2062350)
  
• 2.2pF capacitor (http://www.mouser.com/Search/ProductDetail.aspx?qs=qkDYIeTQ%252bEmpfZ7yvepLxg%3d%3d)
  
• 220pF capacitor (http://www.mouser.com/Search/ProductDetail.aspx?qs=SY6bF4iPirSfxdv%2f%2fjRcVA%3d%3d)
  

Construction:

1. Cut BNC cable in half. Strip insulation about 1", separate shield from center conductor and tin ends.
2. Remove cover from FM25B. Remove plastic back panel and drill two holes just big enough for the cable:
   
3. Thread the cables through the holes. Do this before soldering because you can't do it after!
4. Put heat-shrink tubing over the exposed shield of the cables to prevent it from shorting. Shrink. Then put some bigger heat-shrink tubing over the place where the center conductor separates from the shield. Shrink.
5. On the FM25B, locate C20. (It's the blue 10µF capacitor.) Solder the "MPX out" cable's center conductor to the negative lead (the one towards the rear of the transmitter), as in this picture:
   
   (If you're good, you can do it without covering the potentiometer, like I did.)
6. Find a ground point nearby. (Sorry, I'm doing this from memory.) The ground points are the big areas of copper (painted green). There should be a feed-through hole that you can solder to. Solder the shield to this point.
7. Find D7 (look at the picture above). Solder the 100k resistor to the cathode (the lead towards the front of the transmitter). Keep the lead as short as possible because it will have VHF signals on it.
8. Now for the tricky part: Solder the 2.2pF capacitor between the free lead of the resistor and ground. Ground is at the anode of D7. Again, keep the leads as short as possible. You can see this capacitor in the picture above to the right of the resistor and diode.
9. Solder the 22pF capacitor between the junction of the resistor and capacitor you created in the previous step and the center conductor of the "RDS in" coax. You can see this in the picture above. The coax is the one on top.
10. Find another ground location and solder the shield of the coax.
11. You're done! Get everything back in the box and put the transmitter back together. But first, label the cables so you know which is "MPX out" and which is "RDS in".
12. Connect the cables to the Pira32. The Pira32 should be with JP1 set to 1-2, and JP2 open. Power the transmitter and the Pira32.
13. Wait 5 minutes for the FM25B and the Pira32 to warm up, then adjust TR2 on the Pira32 until LED2 lights. This adjustment is tricky because the signal on the "MPX out" cable is much lower than the Pira32 expects. However, I was still able to get the Pira32 to lock on the 19kHz signal by adjusting TR2 carefully.
14. Turn TR1 very low. The FM25B does not need a large RDS voltage. It should be set so that the RDS signal is received reliably, but not too much so that it distorts the audio.

[Greg]

That's it, I thought it was the 30 that steven modified, I gues it isn't much different.

thanks

greg

[schristi69]

Ok, now I am totally confused. I have been reading in another thread about adding RDS to your show. I have seen a lot of mention of EDM-LCD-RDS and only find FM transmitters on their site. I was under the assumption this was an add on thing to add RDS. From what I now understand the EDM products are FM transmitters with the RDS encoder integrated correct? In order to use RDS with my Ramsey transmitter I have to buy a separate RDS module and modify my Ramsey to interface with it correct? Anyone plan on building/selling a plug and play solution for us electronics challenged people? Or maybe a kit with detailed instructions? Are there any other solutions out there?

[Steven]

schristi69 wrote:

From what I now understand the EDM products are FM transmitters with the RDS encoder integrated correct?

The EDM-LCD-RDS is an FM transmitter with the RDS encoder integrated, correct. I used it this year in my show and it works and sounds great.

In order to use RDS with my Ramsey transmitter I have to buy a separate RDS module and modify my Ramsey to interface with it correct?

That is correct.

Anyone plan on building/selling a plug and play solution for us electronics challenged people? Or maybe a kit with detailed instructions? Are there any other solutions out there?

The least expensive solution, assuming you already have a transmitter, is to buy a Pira32 RDS encoder for €75 (~$108), build it yourself, modifiy your transmitter, and connect them. You'll also need another power supply.

The easiest solution is to use your existing transmitter as a "backup" transmitter, and buy an EDM-LCD-RDS for $220 + S&H.

There are other solutions, but most of them are both more expensive and more complicated.

[schristi69]

Thanks. I found another thread in another forum where they have done the miniRDS mod to a Ramsey FM30 like mine. Ordered the kit today. I will give it a shot and can always go the other route if I break it.

[jimswinder]

This might be a little off subject...but will a RDS Transmitter work with ZARA Radio? Or will it only display the Sequence Text Info using the text created in LOR?

[-klb-]

It will depend on the RDS unit, and the software used, but generally yes. You can have the Mini RDS software watch the Zara currentsong.txt file, and have LOR write to that same file, so you get RDS for both LOR and Zara. MagicRDS that works with the PiraRDS unit, if I remember correctly, allows for a schedule of time frames that it will look to different sources for RDS source text.

[Greg]

I modified the fm 30, if I get a chance I will take the cover off and try to get some pictures for you if you like. it was a very easy modify. I was even able to use the power from the transmitter also and it is on the switch, so when the transmitter is off so is the mini rds unit.

[schristi69]

Great thanks

[mrellis63]

Hi Greg,

I have the Ramsey FM30 and want to mod it to work with the
Pira32 RDS. Would you mind posting your info on how you connected the Pira32 MPX IN and RDS OUT and what parts etc.

Thanks,

[Greg]

I basicaly followed stevens lead with this modification posted above and did have some help I will do my best to explain what I did

I have my mini rds mounted inside the transmitter, it is a little tight getting on and off but makes everything nice and neat. You can power the mini rds off the power for the transmitter the red wire from the power leads is the positive side the negative side can tap off one of the pcb board (use a meter to find the power) there are four mounting spoots directily behind the power switch, one of those will work.



the rds output pin 2 (ground) can mount to the same trace as you negative power supply feed, the next step I found easier to do on the back of the transmitter pcb board, the feed to the transmitter (pin 1 on the rds output) I inserted at R10 position on the transmitter. Prior to insertain I used a .001uf capacitor and and a 3.3ohm resistor inline.

This worked for me








Attached files

[Don In Kenner-LA]

Hi All:

I purchased mine off of ebay its a 0.5 watt tranmitter I thing I paid 20.00 for it came from china boy was I surpized I had to put it on the floor in a closet and it still brodcast over 3 blocks in any direction and I can select any freq. I got to say it was a gret buy..

Don In Kenner,LA

[Greg Young]

After seeing all of the interest in RDS, and needing another little project to do (as all my electronic projects are done) I decided to incorporate the Pira 32 encoder into my Ramsey 100B. It went in quickly and easily.

Upon activation of the software I noticed it was not responding to the pc, though I did have the RDS signal being transmitted (display on the radio showed the RDS default "*rds*"), so I knew the hardware side of things was OK.

After a little trial and error I found I needed to make one change in the software commands, and the encoder then received data from the pc. I had to change the data transfer speed to slow, to get the encoder to work. I left it bidirectional, but had to change the speed.

This puzzles me as I have a good serial to USB device (the keystone unit that LOR sells- which on my pc is using com 7 with the standard 9600, 8,N,1). The pc is a dual core 2.3 gig processsor running win XP media center, with 2 gig of ram. The only programs I had running were the mini-rds and LOR.

Did any of you using running RDS encounter this? Any thoughts?

Greg

[pdowns]

Greg,
Were you using MagicRDS software? I have an EDM unit and I had terrible results with the RDS feature last year. It rarely worked. I could get it to work and then later it would stop. I'm encouraged to think that slowing down the speed could help. The slowest speed I can specify in MagicRDS is 1200 bps. But that's plenty fast for the short strings of text we send.

[Greg Young]

Hi Pat:

I am using the miniRDS software that I downloaded from pira.cz, who make the chip encoder I used (pira32).

I am not running the magic software.

MiniRDS seems to work fine, but I am baffled as to why I have to tell the mini RDS software in the preferences section, port subsection to slow down (I didn't change the serial port parameters from their default 9600 baud)..

Greg

[Greg Young]

I must be getting old, as I really mispoke!

I purchased the miniRDS encoder module, (not the pira32). which is small, inexpensive, and easily fit into my Ramsey, hence the use of the minirds software! It seemed like a straight forward install (it was), and based on what folks were saying it seemed like it would be fun to operate....

I have spent the last 2 days trouble shooting. It works as described, with all the default settings except one - the need to slow the port communication speed down (in the preferences section, under port options). It works well bidirectionally, so communication is fine. (Am using the keystone USB/serial convertor I got from LOR a while back, as I know that is reliable...)

It's features all work as advertised, except for one major software issue that I can not solve. I have each musical selection in LOR calling a .bat file that changes the musical text being transmitted (title and author) to the RDS encoder.

Whenever LOR calls the .bat file to be executed during a show I see the data appropriately change in the miniRDS software in the tab 2 (dynamic PS) section, but it never gets transmitted to the chip and sent out! The chip keeps sending out the last selection made before LOR started to operate.

As soon as I shut down LOR, and either call another bat file manually to change the musical information, or simply push the send button on the miniRDS software, all the information gets transmitted to the chip, and the RDS is scrolling on the receiver again 100%.

I tried running another program (my OTS software), which does not use a comm port, and it doesn't work in that case either, so it does not seem to be related to comm ports, but rather seems related to other software running on the pc. :?

In fact when I am running any active software, it seems the miniRDS software will not transmit the information it has into the RDS chip, until the other software stops running.

I am running a Dell XPS 400 dual core 3.2 gig pc with win XP media center edition, service pack 3, and have plenty of RAM for XP (2 gigs).

Can any of our computer software experts out there offers any thoughts as to how I might be able to get this to send its data to the RDS chip when running other programs?

Is it possible to run miniRDS in some sort of virtual window that will allow it to communicate without interference with other programs that are running on the pc??

The pira folks don't seem to have an answer, as they have not heard of this happening anytime before, but were willing to have me send the RDS chip back. I really don't think that will help, as again everything works as described unless other software is running on the pc...

I would really appreciate any assistance/thoughts folks could offer!

Greg

[Steven]

Greg Young wrote:

(Am using the keystone USB/serial convertor I got from LOR a while back, as I know that is reliable...)

It sure sounds like a communication problem, and this is why: Although you hook it up to a serial port, the MiniRDS encoder does not use normal serial communication (RS-232). Instead, it uses I²C, a protocol normally used on a single circuit board for communication between IC chips. The normal RS-232 serial port isn't designed for this, and as a result, it may have trouble depending on the characteristics of the serial port.

The cable that connects the MiniRDS with a serial port doesn't even use pins 2 & 3, the transmit and receive pins. Instead it uses the modem control pins, which means the timing has to be done by the MiniRDS application itself, not the hardware or even the driver. Clearly, if other applications require CPU time, this messes up the timing.

I use the Airlink101 serial adapter with a Dell Dimension 4500S with a Pentium 4 1.8 GHz running Windows XP SP3, and MiniRDS worked for me last year, but I haven't tried it with the current version of LOR.

[Greg Young]

Thanks for the advice Steve!

I am surprised the pira folks didn't suggest something to that effect. They seemed clueless on this problem at least. On a positive note they were however quite prompt in replying to my concerns..

I will look into Airlink, and let folks know how I make out. I can't believe I'm the only one with an issue like this, so what I find out may help others (like it did with the Chauvet and LOR IDMX issues I ran into last year...)

And I thought I would just spend $30 and play around with simple toy!:shock:

I should have known that even if something seems easy, it usually isn't quite as easy as it seems!

Greg