Jay, I had the Realtek ALC889 chipset (older Realtek audio). The biggest issue I had is I couldn't get it loud enough without it cutting out. I had to use an Aphex as an amplifier and that barely cut it. Then the frustrations with the overshoots, static noise and humming. It was terrible.
I hope you like the new dongle. It seems well worth the small price tag. I'm running RDS through it with no problem. I'm still using stereo encoding on the transmitter. However, now my stereo separation doesn't degrade as much with distance. Also, it was plug and play in Windows 11. No driver installation necessary.
I finally got home and was able to try this thing. It sounds freaking amazing. I did a quick and dirty test by resetting all my PEQ and tilt settings to 0. The sound is phenomenal. Also, no static noise or interference. Highly recommended. No more screwing around with tilt settings and oscilloscopes. The loudness is blowing away every commercial FM on the dial.
Due to my frustration with onboard Realtek audio and it's shortcomings, I'm going to give one of these a shot. It's DC coupled and supposedly supports 24 bit / 192kHz audio.
With the Realtek, setting my audio processor to output above 96kHz results in no audio, suggesting that Realtek may be capped at 96 kHz. This is despite Windows reporting that it's 192 kHz capable. Hopefully this dongle solves that issue as well as helps me avoid overshoots and having to do tilt compensation.
Gents, thanks for taking the time to reply on my issue.
Kage, thanks for the clarification on the pilot signal. I have made sure it's around 10 percent when letting the audio processor do the stereo via L, R or Mix of both channels. That works great, but the loudness is lacking. I assume the built in stereo encoder in the transmitter would be up to the job, but perhaps that is not correct. My sound card is 192 kHz and I've hooked it up to an oscilloscope. Everything looked good there. Perhaps it's just the weak signal, as you say and the car radio blending the left and right. Also, it's very hard to find a truly free radio signal in today's metropolitan areas. Perhaps interference could be the problem?
tron24, I believe the sound card is AC coupled as most are. It's onboard realtek line out. Perhaps I'm wrong on this. If it's AC coupled then this is likely my issue as it seems I've had to work very hard to get even moderate sound, whereas I set up a station for a friend and it sounded 50 times better with little effort. Pre-emphasis is set up correctly - disabled at the transmitter via dip switch and enabled at 75 microseconds at the processor.
I'm glad this forum is still around. I really appreciate the help I've received here in the past.
I have a new issue. I'm currently using the stereo encoder on the FM transmitter I have. It sounds awesome listening on my car radio in the garage. But if I crank the power up and drive around the neighborhood, I noticed the stereo separation almost goes to a mono-like sound as I reach the end of the block; even though the signal is still clear. I've tried using the stereo encoding on the audio processor and doing either the right, left or mono mix of both sides. This sounds pretty good, but I can't get the same loudness that I can with using the transmitter's stereo encoder. I'm using the pre-emphasis on the audio processor and have it disabled at the transmitter. Just wondering what the issue might be. Thanks.
The sound quality is amazing, but dependent on the quality of your audio processing.
The audio inputs are 600 or 10,000 ohms (adjustable with the dip switches on the back). This means that connecting a standard 400 ohm audio device won't be adequate (even though Camel RF says it is) because the volume level will be too low. In order to get normal volume level, I had to overdrive my sound card which caused it to disconnect from the PC. I used and Aphex amplifier to correct the issue (available cheap on ebay).
Also, I had to purchase some XLR audio cables. There are no optical or RCA audio inputs on the transmitter. The antenna output is a type N female. This created a confusing mess trying to connect an SWR meter with UHF connections and a signal attenuator with BNC connections inline with the antenna. Local HAM radio shops or ebay are good sources for cables and adapters.
I like that pre-emphasis can be turned off via dip switch settings, which helps with using professional audio processing. Also, the HMI controls let you select audio input as stereo, L-R Mix, L or R inputs. So if you wanted to try using stereo encoding at your audio processing you can do that. Personally, I didn't have good luck with this. I was able to get great stereo separation by using the L audio input, but loudness was lacking. I'm not sure why as I adjusted my audio processing controls with an oscilloscope. So I just use the transmitter's stereo processing with pre-emphasis disabled.
Lastly, the fan is loud, whinny and irritating. I replaced it with a low db one as I couldn't stand the noise.
For RDS, I use an older version of stereo tool and run it in the background with Task Scheduler. It works very well. I set it to use an unused sound device as the input and then set the output to my 192 kHZ capable sound card. This works independently of other software I use for audio processing.
I'm in the US. I saw this on a friend's car radio several years ago! It actually came up with the station logo and everything. Perhaps the logos were pre programmed into flash memory or it was getting the logo through cell data via bluetooth connection. Not sure.... I guess I was mistaken for thinking it was done through RDS.
Sorry for all the questions. I'm glad this forum exists. Just wondering if anyone knows if there's any PC software that can broadcast a station logo via RDS. I noticed on commercial radio stations they have their logo appear on a capable radio. I would like to do the same thing.
Thank you very much for the response. I tried a hooking a bluetooth receiver connected to my phone directly into the Aphex. With it being unprocessed audio it sounded horrible. Unfortunately, I only have FM processing on the PC I'm using. The Sound card is an onboard Realtek (192 KHz) with a regular 1/8 inch speaker out jack. All the other jacks are either for surround sound speakers or a microphone. The jack I'm using shows as "speakers", rather than "headphones", in Windows Sound. I plugged some headphones into it as an experiment and it still showed speakers.
I believe you're correct that the issue is trying to drive pro gear with consumer-based hardware. I'm using the Aphex as an amplifier but it seems to fall just short of doing the job adequately. Do you have any recommendations on computer sound cards that might be better suited to run a radio station?
That's interesting regarding the impedance. Perhaps that would explain why I experienced inadequate highs when setting the transmitter dip switches to 600 ohms rather than 10000 ohms.
I was actually overmodulated. I lowered the sound card level which fixed that issue. Then I changed some settings in the audio processor (Breakaway Broadcast Processor) for a more aggressive, punchy sound. It's still not 100% but much better. I'm not sure what the clip warning is for. I believe it has something to do with the sound bars in Windows Sound pinging to maximum. The transmitter doesn't have any built in processing other than pre-emphasis, which is disabled, and stereo (enabled).
I have a pretty complicated setup. Things sound good and modulated correctly, but something is just a bit off that I can't quite put my finger on.
Here's what I have:
FM audio processor reference level: -3.5 db (60 Hz square wave tilt and coeff adjusted with an oscilloscope - dc coupling turned off) Stereo Mix and input sound card: 0 dB Output sound card: -23.2 dB Aphex 10/4 interface: +6 dB per channel FM transmitter audio setting: +6 dB per channel
I have 1/4 analog audio from the computer to RCA input on the Aphex. Then XLR from the Aphex to the FM transmitter.
The FM transmitter has dip switches for 600 ohms and 10k ohms. Currently set to 10k as 600 ohms results in slight loss in highs. FM transmitter pre-emphasis is turned off; pre-emphasis handled at the audio processor. Fm transmitter set to stereo - (using L, R, or Mix input resulted in loss of volume with mplex output).
The Aphex has a button for 600 ohm termination resistor which is turned off, but makes no difference in sound either way.
The output sound card doesn't seem to like being turned up too loud with the input in the FM audio processor being set as it is. If turned up too much, it will distort then disconnect from the OS. That's why I have the Aphex and Transmitter set to +6 dB to add the extra boost.
I'm just wondering if I'm doing something wrong. I get constant clip warnings in the FM processor, but it doesn't seem to be audible or cause any issues. The output sound card in Windows Control Panel pings at the last (uppermost) bar with fluctuation up and down (3 to 4 bars). This seems desirable to me.
I have different software running in the background to output RDS to the same sound card. It makes no difference in sound weather it runs or not.
End result is very slight loss of luster compared to commercial FM. Stereo separation is great and the RDS comes through instantly. Any tips on levels would be appreciated.
If the transmitter is on low(est) power, do you still hear it? It could just be your proximity to the antenna. It often creates a 60hz like buzz that sounds like a ground loop problem.
Any recommendations on how to remove a 60 Hz ground loop buzz? I have 1/4 '' from the computer to an Aphex 10/4 interface. The 1/4'' to RCA between the Aphex and computer has a filter to remove background noise, but it doesn't work 100%. From there, it goes XLR out to the transmitter. Unfortunately, all equipment is right next to each other and it's rat's nest of wires. I've read that its best to plug everything into the same outlet. All devices are plugged into a sign wave UPS. The problem seems to exist with the XLR cables from the Aphex, as I can move them around and reduce, but not eliminate, the noise.