Static Problem with Ramsey 30B FM Stereo Transmitter

[jerrylcooper]

I purchased a Ramsey 30B FM Stereo Transmitter last summer in 2015 to transmit my music sequences for my outdoor Christmas Yard Display. The transmitter is sitting on a shelf inside my garage in the southwest corner and connected to my wall mounted Light-O-Rama Controller Pro Series LOR1602Wg3-MP3, which has a built in G3-MP3 Director which gives me the capability to insert a Scan Disk card which contains musical sequences to accompany the computerized light show.  Viewers can view the light show and hear the music by tuning their car radio to a FM frequency 88.3 which is not being used in our area. My original FM transmitter did a poor job, so that is why I purchased the Ramsey after reading good reviews. I am using the whip antenna that came with the Ramsey transmitter.

 

My lights are on my house (icicle, rope & string lights), bushes (net lights) and the around the yard perimeter (string lights).  I have 24 sets of RGB (Red, Green, and Blue) cosmic color pixels connected to the top of a 25 foot aluminum flagpole in the southwest corner of my front yard my front yard which the 24 light strings staked to the ground in a circle measuring about 20 feet in diameter.

 

I also have a large Sycamore tree in the northwest corner of my front yard about 35 foot in height containing about 12 mini-light strings as well as a Maple tree in the far southwest corner of my yard, a small tree in the southeast corner of my yard and another small tree in my northeast corner of my yard.

 

My house sets on the northeast corner of a corner lot. My front yard is on the west side where most of the light display is and my garage door and driveway are on the south side of the house. Most viewers park their cars in the street in front of my house which runs north/south. As long as they are on the south end of the street, their car radio reception is great but as they move further north, the reception is disrupted by heavy static. I suspect the static might because of the 25 foot aluminum flagpole and or the trees because there is no static between the transmitter in the southwest corner of the garage to the south corner of the street, The flagpole and large Sycamore tree are further north and come between the transmitter and the parked cars along the northern part of the street.

 

Do you thing they may be creating the static? If so, would a dipole antenna help? Should it be mounted in close proximity to the FM transmitter inside the garage or outside the garage on the roof which is about 20-205 feet high? Any other suggestions? It is a great show but I received a lot of complaints about the static from my viewers.

 

Edited February 28, 2016 by jerrylcooper
spelling error

[ebrown1972]

20 minutes ago, jerrylcooper said:

I purchased a Ramsey 30B FM Stereo Transmitter last summer in 2015 to transmit my music sequences for my outdoor Christmas Yard Display. The transmitter is sitting on a shelf inside my garage in the southwest corner and connected to my wall mounted Light-O-Rama Controller Pro Series LOR1602Wg3-MP3, which has a built in G3-MP3 Director which gives me the capability to insert a Scan Disk card which contains musical sequences to accompany the computerized light show.  Viewers can view the light show and hear the music by tuning their car radio to a FM frequency 88.3 which is not being used in our area. My original FM transmitter did a poor job, so that is why I purchased the Ramsey after reading good reviews. I am using the whip antenna that came with the Ramsey transmitter.

 

My lights are on my house (icicle, rope & string lights), bushes (net lights) and the around the yard perimeter (string lights).  I have 24 sets of RGB (Red, Green, and Blue) cosmic color pixels connected to the top of a 25 foot aluminum flagpole in the southwest corner of my front yard my front yard which the 24 light strings staked to the ground in a circle measuring about 20 feet in diameter.

 

I also have a large Sycamore tree in the northwest corner of my front yard about 35 foot in height containing about 12 mini-light strings as well as a Maple tree in the far southwest corner of my yard, a small tree in the southeast corner of my yard and another small tree in my northeast corner of my yard.

 

My house sets on the northeast corner of a corner lot. My front yard is on the west side where most of the light display is and my garage door and driveway are on the south side of the house. Most viewers park their cars in the street in front of my house which runs north/south. As long as they are on the south end of the street, their car radio reception is great but as they move further north, the reception is disrupted by heavy static. I suspect the static might because of the 25 foot aluminum flagpole and or the trees because there is no static between the transmitter in the southwest corner of the garage to the south corner of the street, The flagpole and large Sycamore tree are further north and come between the transmitter and the parked cars along the northern part of the street.

 

Do you thing they may be creating the static? If so, would a dipole antenna help? Should it be mounted in close proximity to the FM transmitter inside the garage or outside the garage on the roof which is about 20-205 feet high? Any other suggestions? It is a great show but I received a lot of complaints about the static from my viewers.

 

I do not know how close you have the transmitter sitting next to the G3mp3  director but I would have the transmitter about 10 to 15 feet away from it. I would bet you have the transmitter close to it. I use a computer for my show but if I have the transmitter close by I get static. I moved it about 12 feet or so away and the static was gone.

[wbaker4]

Sorry to report that Ramsey Electronics is no longer selling kits.  Too bad.  They were the best quality and nice variety.  I missed buying their nixie tube clock kit.

[Need more lights]

LED's are known for causing white noise. I have to place my antenna strategically so I don't get noise too.(All LED display) I would place bets on the RGB pole. You could try spliting the antenna to get a line of site around the pole or get above it by going up the outside of garage. Truely it's trial and error. 

I run my antenna wire along the bottom of my porch just on the other side of my pillars, so there isn't any LED's between the antenna and my veiwers. Solved my trouble. 

[Orville]

I doubt the transmitter near the MP3 Director is the culprit.  I used an older DC-MP3 Director and my MBB Eclipse-4000 transmitter sat inside the box directly across from the director unit, ran my display like this for 3 years before my director went belly up.    Never had any issue with static with both in the same enclosure.

But I did keep the enclosure as far away from the lights, especially L.E.D. lights, as possible.  They can cause interference and the static issues if they are too close in proximity to the transmitter.

And sometimes the static interference can come from fluorescent lamps as well, if you have those type of light fixtures in your garage or house, they can also cause a lot of static, as can L.E.D. standard lamp bulbs, and CFL bulbs, especially if they may be on the same circuit as your transmitter power supply or in close proximity to it and the transmitter.

 

Had to remove some of my CFL bulbs and go back to the old incandescent standard lamp bulbs when I was using the MP3 Director and Transmitter, still have to keep CFL's away from my transmitter as they do make an awful static interference if they are anywhere near the transmitter or its antenna.

 

Just some other issues you may want to look into if you use these type bulbs in and around your home.

 

And one other thing you can do is add ferrite coils on the audio cable, 1 at each end near the male plug that plugs into the transmitter and out from the MP3 Director, these help cut down on outside interference that can affect the audio output/input from Director to Transmitter.  Because sometimes unshielded audio cables can act as an antenna and pick up electrical and other noises that can generate static.   If you can get them, it's best to buy really good audio cable that is both shielded and has these ferrite coils on each end of the cable.     The latter is what I used on the DC-MP3 Director to FM Transmitter, and now that I use a computer, I still use these type of audio cables to cut down on any outside interference and I rarely have any static on my transmissions from the transmitter.   But even with the better audio cable, the bulbs mentioned before can still cause interference, it'll be cut down a bit, but still too noticeable for my liking.

 

Hope this may help get that static you're having under control!

 

BTW: I just use a small rubber duck antenna on my transmitter and it was inside the housing and it still worked great.   I've never needed a larger or longer antenna, and I get excellent range with this antenna, been using it for 3 years, transmitter on 365/24/7 with no problems.

[jerrylcooper]

Thanks for your suggestions,

[jerrylcooper]

Thanks for the feedback!

[Old Sarge]

it may be possible that you are over driving the transmitter with to much input power or you may have it set a little to high as to the poutput on it. Also as was said.. try putting the filters on line and that may help to or using a higher rated wire to connect it.. you may be picking up some static threw the wiring if it is not shielded or a good quality of wire.

[jerrylcooper]

Thanks for your feedback as well as your service to our country!

 

Looks like we have something else in common- a CIB and jump wings if I eyeballing your photo correctly.

[Eric walls]

I had my display set up for Halloween and all I heard was static this year. I searched this forum and saw this thread and one thing that struck me is one of the above posts mentioned to keep the transmitter away from the led lights. The only thing I changed this year was the placement of the transmitter, I put it on top of a hedge that had net lights. Now I'm wondering if that is the culprit?

When I get home from work I'll have to place it somewhere else. I'm running my show from a director so I have limitation where to put it. I'm also going to try and plug the transmitter into its own circuit. 

Thanks for the suggestions. I have the CZH-08 from Amazon a few years ago, 60 bucks and works great when it's not throwing static.

[Mr. P]

4 minutes ago, Eric walls said:

I had my display set up for Halloween and all I heard was static this year. I searched this forum and saw this thread and one thing that struck me is one of the above posts mentioned to keep the transmitter away from the led lights. The only thing I changed this year was the placement of the transmitter, I put it on top of a hedge that had net lights. Now I'm wondering if that is the culprit?

When I get home from work I'll have to place it somewhere else. I'm running my show from a director so I have limitation where to put it. I'm also going to try and plug the transmitter into its own circuit. 

Thanks for the suggestions. I have the CZH-08 from Amazon a few years ago, 60 bucks and works great when it's not throwing static.

One other thing to consider about the CZH-08 as I have been using that unit for about four years, don't turn the volume knobs on the front of it over halfway. It tends to gain static and starts to distort, let the viewers in the cars turn their volume up if they need it louder.

[Eric walls]

Ya, I saw that too....I will check when I get home from work today. I may have turned it up because I wanted the music to be louder but it could have created just more distortion.  I'm also going to stop and get a new audio cord so I hope I can solve this. Last year it came through pretty clear, so I must have changed something. I'll have to set it up exactly like I did before and check one thing at a time. Kinda frustrating to have it all set up and then hear static.

[k6ccc]

One of the first things to test with a report of static on the FM transmitter, is to determine if the transmitter is transmitting a clean usable signal that is received with static when you get far away from it, or is the transmitter producing a unusable distorted signal.  Fortunately, that is very easy to test.  Listen with a receiver only a few feet from the transmitter.  If the test signal is clean, then the transmitter is generating a clean signal.  If the signal is noisy when you get some distance away (like out where your audience will be), then the problem is poor radio link performance.  A better antenna might help.

If the test signal is noisy when you are listening only a few feet away, then the transmitter is producing a noisy signal and no amount of antenna or feedline changes will improve it.  For our purposes, the most likely reason for distorted audio would be over-driving the audio.  Depending on the transmitter, you may be able to turn down the audio level at the transmitter.  You may be able to turn down the audio at the source.  Since most of you don't have the radio test equipment that I do, my recommendation for setting the audio level is to start by turning  the audio down all the way.  If the problem is that the audio is over driving the transmitter, it should should be clear (albeit quiet) when the audio is turned down.  Then slowly start turning up the audio level while you monitor it.  As you turn up the audio at some point, you start hearing the the audio start distorting.  Turn the audio down a little until it is clear again.  Very important note.  You need to do this test with either a song that is very loud, or better, a test track that is at full volume.  You can create a test track with Audacity.  Yes, it's obnoxious to listen to for very long!

---  WARNING: TECHNICAL CONTENT  ---

I'm going to include some details.  Most of the levels I'm going to give are for example only, and may well not apply to your equipment.  Let's start with the transmitter.  The transmitter takes the audio and uses that to modulate the radio signal.  The higher the audio signal, the greater the modulation of the radio signal.  At some point, you will get to an audio level that is greater than the transmitter can handle.  At that point, the transmitter starts generating a distorted signal.  In all likely hood, however the transmitter will be able to handle a quite large signal.  It can handle such a large signal that the transmitter will produce a signal that the receiver can't handle it.  The measurement that is used to measure the modulation level of a FM transmitter is KiloHertz (KHz) of deviation - these are real numbers, BTW.  For the FM broadcast band, the standard is 75 KHz of deviation.  If your transmitter is producing 100 KHz of deviation, your receiver is going to distort because of the over-modulated signal.  For the level of radio transmitters that most of us are using, the transmitter is capable of producing a signal that is substantially over modulated.  In "real" FM transmitters, there are deviation limiters to prevent over modulation, but the equipment most of us use, have little or nothing in the way of deviation limiters.  In other words, your transmitter will likely generate a signal that is substantially over 75 KHz of deviation if you give it enough audio.  When listening on a FM receiver, it will sound distorted, even though the transmitter is actually generating a clean (but over-modulated) signal. The distortion is actually in your receiver.  The solution is to reduce the modulation of the transmitter.  Note, for those with experience with AM radio (notably Citizens Band - aka CB radio), over-modulating an AM transmitter DOES produce a distorted signal.  Without getting into the details, with an AM transmitter, there is a hard limit that can not be exceeded without causing distortion in the transmitted signal.

For any given transmitter, there is a given amount of audio signal required to produce 75 KHz of deviation.  For example, if your transmitter requires 0dBm of audio to produce 75KHz of audio, it will always produce 75KHz of deviation when there is 0dBm of audio presented to it.  If the audio is half that (-3dBm), the transmitter should produce 37.5 KHz of deviation.  Similarly, if the audio is twice as high (+3dBm), the transmitter will produce 150 KHz of audio - unless there are circuits in the transmitter that prevent it from going that high.  BTW, to keep this simple, I'm ignoring pre-emphasis.  It's supposed to be a linear relationship between the audio level and the modulation of the transmitter.  If you don't understand the dBm scale and want to, see:  https://en.wikipedia.org/wiki/DBm

In most of the transmitters that we use, there is an audio level adjustment.  That adjustment is there to reduce to audio level that is being fed to the transmitter itself.  Again using the example of a transmitter that requires 0dBm of signal for proper full modulation, if the adjustment is turned all the way one way, no adjustment is being made, but when the adjustment is turned all the way the other direction, the signal is reduce by some amount.  This way, if you audio source is producing let's say +20 dBm (100 times too much for the transmitter), you can use the adjustment to bring it back down to the proper level for the transmitter.  If your transmitter does not have an adjustment, then you must adjust the levels somewhere else.  Generally that means at the source.  If the source is a computer, you can adjust the levels with the audio controls of the PC.  Note, that for a PC, generally you are wanting to use the "line" output which is generally green,and not a speaker or headset audio output (if there are more than one output).

Earlier I talked about using Audacity to produce a test track.  Although the waveform display in Audacity is shown in a relative level (-1 to +1),there is a volume display near the top that shows the level in dBm.  Zero dBm is the same as 1 in the waveform display.  For whatever song you are playing in Audacity, the levels should be just below 0dBm for all songs at their peak.  A test tone for adjusting your transmitter should be a 0dBm.

OK, I'm sure most of you have glassed over eyes if you read this far....