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Messages - OgreVorbis

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Software / Re: Pitch shift idea
« on: July 06, 2018, 0205 UTC »
So, I just tested it in audacity. Audacity doesn't have the feature to pitch shift only a specific range, so:
I added the track twice.
Put a high pass filter on the first one.
Pitch shifted the first one.
Then put a 2.5Khz low pass on both tracks.
Played them together.

It sounds about the same as it would if you just used an EQ to the higher frequencies. Maybe it could be done better though. This was just me messing around. You could probably optimize the pitch shift to make it better. You might get distortion if the pitch shift isn't right.

Software / Pitch shift idea
« on: July 06, 2018, 0020 UTC »
So I was thinking about the limitations of audio bandwidth for broadcasting. I was wondering what it would sound like if instead of filtering at something like 2-5khz (which is around the standard), you instead pitch shift down everything above that. I don't mean pitch shift everything, just what is above where the filter cuts off. What would this sound like? Clearly it would sound lower, but would it improve the quality of the music without using more bandwidth?

Also is this possible in any software (like audacity maybe)?

Shortwave Pirate / Re: unidentified 6810 AM 0102 UTC 5 July 2018
« on: July 05, 2018, 0313 UTC »
How was the modulation?  ;)

This is my first transmission and I don't have a PEP meter, so I just kind of winged it.

UNID 6810 AM S5 in NY

0103: Paul Basic "Cloak & Dagger" (that was a great movie back in the day)
0111: Keeno "Piano Only"
0117: Keeno "Eos"
0121: Helios "Every Passing Hour"
0126: Galimatias "Noelle's Eloquence"
0132: Tom Middleton "Serendipity"
0136: Off the air

Impressive ID. You must have used Shazam?

Equipment / Re: AM broadcast pirate PWM
« on: June 14, 2018, 0659 UTC »
I would tread carefully.  I've heard some no-so-glowing reviews of his builds, especially his high power stuff.  I would also like to see some spectral measurements and see if the things can meet NRSC specs for emission.

There is a reason that commercial stuff runs in the $10/watt range... Like a friend of mine used to say about, uh, large women...lots of fun, but don't get caught.


The rig I have from him is a PWM. The first harmonic was -35-40 dB I think, but it's been a while since I looked. He's got a 250W on ebay with PWM. So the harmonics are not great, but there where no spurs I could detect. You could easily add your own LPF. Mine came with a 3 pole instead of the 4, which is probably why it's not the best. His pics showed a 4 pole though.

All the pll.gr TXs are not PWM and they're not made by the same "amhercules" guy.

After some more searching ebay, these look better:
3-8 MHz PWM: https://www.ebay.com/itm/PWM-with-DDS-Class-D-AM-Transmitter-for-80m-40m-Bands-Assembled-and-Tested/323265554444
500-1710 kHz: https://www.ebay.com/itm/PWM-with-DDS-Class-D-AM-Transmitter-Assembled-and-Tested/323261380658

Equipment / AM broadcast pirate PWM
« on: May 01, 2018, 0410 UTC »
I am making this post to show some good options if you're looking to pirate on AM broadcast band and are not skilled enough for home-brewing a transmitter.


Broadcast Announcements / Testing CW on 14400 khz
« on: September 05, 2016, 2117 UTC »
I'm testing 15W CW on 14400 right now in east coast US. Maybe later AM.

General Radio Discussion / Re: Why 69xx kHz?
« on: May 03, 2016, 2015 UTC »
After some research, it looks like the actual range is 6770-7000. It seems like this band aligns with the "land mobile" band right under 40 meters. Are there any specific stations to watch out for here (other than 6903, 6913 and 6915)?

How about the "land mobile" designations above and below the 20 meter band (13.87-14MHz and 14.35-14.99MHz)? Is there anything to watch for there? Apparently the 20m band is the most popular during the day?

I plan on operating AM. What is the normal audio bandwidth for AM on shortwave. Is it the same as the broadcast band (10khz)? Can I use whatever I want? My transmitter can go up to 50khz, so I'm deciding where to filter the audio.

I know these may seem like obvious questions to some of you, but I am not a ham, and I'm new to shortwave. (I do have all the equipment (spectrum analyzer) to make sure I'm not putting out any harmonics or spurs, though.)

Thanks for all the help!

General Radio Discussion / Why 69xx kHz?
« on: May 03, 2016, 0055 UTC »
So I'm new to this forum, but not to pirate radio in general. I pirated before on 1710khz, but the antenna construction is hard and I never seemed to get out very far (plus the ground conductivity where I am is really bad).

Anyway, I want to try pirating on HF and I'm wondering why most people use 69xx khz because for me it would be much easier to make an antenna for around 10-15 MHz. Does anybody listen for pirates around those frequencies? Do they get out as far?

See the graph on this site: http://www.voacap.com/antennas/squeezing-decibels-out-of-dipole/

You can see that if I created an antenna for 10-15, it is very doable to get the peak gain out of the antenna based on the distance from ground. However, if I were to use 69xx, it would be very hard for me to get more than 40ft from the ground and so not much gain...

So would pirating around 10-15 be better?

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