All times are UTC+01:00




Post new topic  Reply to topic  [ 28 posts ]  Go to page Previous 1 2 3
Author Message
 Post subject: Re: Tilt Issue!
PostPosted: Wed Oct 26, 2022 3:57 am 
User avatar

Joined: Sun Mar 06, 2022 3:41 am
Posts: 28
Quote:
That is 30 kHz??? Not 30 Hz??? 30 kHz square wave is a sine wave anyway (the sound card doesn't go high enough). And that high frequency stuff is the actual audio I assume??

It could be that very loud 30-60 kHz tones confuse the SDR, to rule that out, try lowering the level.
Oops! Yes, I meant that the overshoot was 30hz. That would be really considering if that was khz. That was a misunderstanding I read the FM Test tone as in khz. :D Worried me for a second.

Ahem knowing that it is in hz, I tried 30,000hz-30,000hz yep, still same issue. I tried lowering the volume to where it said 61% modulation. It still has the same issue except it would only go down 2%. I would assume that is considered fixed?

Also, asking since I am not an FM transmitter expert since I also saw this while testing 30khz, is it normal when testing 30khz sine that I can see on the RF FTT that the goes outside the 200khz bandwidth? That is also occurring.


Top
   
 Post subject: Re: Tilt Issue!
PostPosted: Fri Oct 28, 2022 5:58 am 

Joined: Fri Apr 06, 2018 4:57 pm
Posts: 23
Location: Brazil
Quote:
Quote:
That is 30 kHz??? Not 30 Hz??? 30 kHz square wave is a sine wave anyway (the sound card doesn't go high enough). And that high frequency stuff is the actual audio I assume??

It could be that very loud 30-60 kHz tones confuse the SDR, to rule that out, try lowering the level.
Oops! Yes, I meant that the overshoot was 30hz. That would be really considering if that was khz. That was a misunderstanding I read the FM Test tone as in khz. :D Worried me for a second.

Ahem knowing that it is in hz, I tried 30,000hz-30,000hz yep, still same issue. I tried lowering the volume to where it said 61% modulation. It still has the same issue except it would only go down 2%. I would assume that is considered fixed?

Also, asking since I am not an FM transmitter expert since I also saw this while testing 30khz, is it normal when testing 30khz sine that I can see on the RF FTT that the goes outside the 200khz bandwidth? That is also occurring.
The transmitter modulator (probably some analog PLL circuit) is very bad. even a raspberry pi can generate a better signal. try BW Broadcast with DDS modulators. or some old transmitter with crystal based modulator. (they're not very stable at startup but soon they get "warm" you will get perfect modulation. Do not fight against the PLL modulator. Even if you get perfect square wave, it will lose frequency with bass and bottom end sounds. Take a look at the power supply too. Bad eletrical levels on the PLL modulator usually does this type of harm to the sound. specially at 30hz

_________________
Need Help? Call me, I can help you have a better sound with your actual audio processor, Analog? Unknown Brand? No Problem At All!


Top
   
 Post subject: Re: Tilt Issue!
PostPosted: Sat Oct 29, 2022 2:19 am 
User avatar

Joined: Sun Mar 06, 2022 3:41 am
Posts: 28
Quote:
Quote:
Quote:
That is 30 kHz??? Not 30 Hz??? 30 kHz square wave is a sine wave anyway (the sound card doesn't go high enough). And that high frequency stuff is the actual audio I assume??

It could be that very loud 30-60 kHz tones confuse the SDR, to rule that out, try lowering the level.
Oops! Yes, I meant that the overshoot was 30hz. That would be really considering if that was khz. That was a misunderstanding I read the FM Test tone as in khz. :D Worried me for a second.

Ahem knowing that it is in hz, I tried 30,000hz-30,000hz yep, still same issue. I tried lowering the volume to where it said 61% modulation. It still has the same issue except it would only go down 2%. I would assume that is considered fixed?

Also, asking since I am not an FM transmitter expert since I also saw this while testing 30khz, is it normal when testing 30khz sine that I can see on the RF FTT that the goes outside the 200khz bandwidth? That is also occurring.
The transmitter modulator (probably some analog PLL circuit) is very bad. even a raspberry pi can generate a better signal. try BW Broadcast with DDS modulators. or some old transmitter with crystal based modulator. (they're not very stable at startup but soon they get "warm" you will get perfect modulation. Do not fight against the PLL modulator. Even if you get perfect square wave, it will lose frequency with bass and bottom end sounds. Take a look at the power supply too. Bad eletrical levels on the PLL modulator usually does this type of harm to the sound. specially at 30hz
Though, knowing the crap I have, yes. It is very bad.

Thanks for the recommendation! Though, one of the reasons I chose PC electronics is due to their low power. I'm only really looking for ~100mW - 15W. I have very limited options. ¯\_(ツ)_/¯

I bought the power supply from them and they say "it's a good power supply." I am not using some random power supply I found around the house...


Top
   
 Post subject: Re: Tilt Issue!
PostPosted: Tue Nov 29, 2022 1:53 am 
User avatar

Joined: Sun Mar 06, 2022 3:41 am
Posts: 28
I hate to bump a dead thread.

What are some good recommendations for a better FM transmitter that's low power? Knowing what I bought and what I got out of it, it is bothersome knowing if I will get something that would be a good FM transmitter. I hope that my doubt is justified

For example, in like this thread: viewtopic.php?t=5828
1) One of the companies recommended is PCS electronics... (ahem the crap I got)
2) Many options from a range of companies.

Really, I don't want anything big. Just something that can work in my car that has MPX input. I don't know what is tested and what's not to provide a good signal.

Plus, I have my dad (let's say he's never been a supportive parent...) saying I should get a new hobby. Oh my lord.


Top
   
 Post subject: Re: Tilt Issue!
PostPosted: Tue Nov 29, 2022 10:09 pm 
Site Admin
User avatar

Joined: Mon Mar 17, 2008 1:40 am
Posts: 10853
Something that can work in your car? I've used a small battery powered transmitter that I bought for 15 euro when I originally developed the stereo/RDS encoder; modulation level isn't perfect (it has a few kHz overshoots) but it sounds good enough after (a lot of) calibration, with decent stereo separation etc. But I assume that that's not what you're looking for? If you're testing it in your car, I can tell you from experience (from using an analyzer in my car) that the power supply that you can from the car battery can be very noisy and cause all kinds of problems.


Top
   
 Post subject: Re: Tilt Issue!
PostPosted: Wed Nov 30, 2022 5:59 pm 
User avatar

Joined: Sun Dec 23, 2018 7:44 pm
Posts: 551
Location: Texas, USA
Quote:
Really, I don't want anything big. Just something that can work in my car that has MPX input.
Excuse me for this suggestion if it's not the end result you're looking for since it does not solve the FM transmission issue. To play processed Stereo Tool audio in my car, I use the built-in streaming engine with Icecast and stream it to AIMP on my phone (for some reason the VLC app won't play it). I control the music with Spotify Connect from my phone and have it play on my home PC. And of course, I adjust the sound via the web interface.

Please ignore this if it's not the approach you need.


Top
   
 Post subject: Re: Tilt Issue!
PostPosted: Thu Dec 01, 2022 1:18 am 
User avatar

Joined: Sun Mar 06, 2022 3:41 am
Posts: 28
Quote:
Something that can work in your car? I've used a small battery powered transmitter that I bought for 15 euro when I originally developed the stereo/RDS encoder; modulation level isn't perfect (it has a few kHz overshoots) but it sounds good enough after (a lot of) calibration, with decent stereo separation etc. But I assume that that's not what you're looking for? If you're testing it in your car, I can tell you from experience (from using an analyzer in my car) that the power supply that you can from the car battery can be very noisy and cause all kinds of problems.
Well, my idea is to mainly use it in the car but I do also want to keep it running inside my house. I am okay-ish with it being noisy in the car. I've been testing it inside my house and it's all over the place while the FM Transmitter has been in the house. I would say that just using that FM Transmitter in the house is pretty annoying to use. I don't know how I would test to check if it's the power supply? Would a bad power supply cause so much tilt + harmonics? How can I tell if it's the transmitter?

In my personal opinion, it would be so cool to be able to broadcast my own signal (even if it's just at home) that isn't shallow, & very loud.
Quote:
Excuse me for this suggestion if it's not the end result you're looking for since it does not solve the FM transmission issue. To play processed Stereo Tool audio in my car, I use the built-in streaming engine with Icecast and stream it to AIMP on my phone (for some reason the VLC app won't play it). I control the music with Spotify Connect from my phone and have it play on my home PC. And of course, I adjust the sound via the web interface.

Please ignore this if it's not the approach you need.
Well, yeah not necessarily what I really want to do. But that's a good idea. Though I don't really want to use any internet and that will require me to use my data plan.


Top
   
 Post subject: Re: Tilt Issue!
PostPosted: Tue Dec 06, 2022 5:34 am 
User avatar

Joined: Sun Mar 06, 2022 3:41 am
Posts: 28
Well, update:

I tried buying a power supply instead of the one that was got from PCS electronics to see if it would do anything. Didn't change anything. ¯\_(ツ)_/¯

Same "harmonics" (if you would call that) in the spectrum analyzer... Just still a bunch of weird behavior...
viewtopic.php?p=72401#p72401

Still feeling the same eh feeling because I am like ¯\_(ツ)_/¯

I feel so scammed LMAO


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 28 posts ]  Go to page Previous 1 2 3

All times are UTC+01:00


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Limited