HFU HF Underground
Technical Topics => Equipment => Topic started by: OgreVorbis on May 01, 2018, 0410 UTC
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Hey,
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.
http://amhercules.blogspot.com/ (http://amhercules.blogspot.com/)
https://www.ebay.com/usr/zercvic2010?_trksid=p2053788.m1543.l2754 (https://www.ebay.com/usr/zercvic2010?_trksid=p2053788.m1543.l2754)
https://www.ebay.com/usr/kleop313?_trksid=p2060353.m2749.l2754 (https://www.ebay.com/usr/kleop313?_trksid=p2060353.m2749.l2754)
https://www.ebay.com/usr/savvi.polyc?_trksid=p2060353.m2749.l2754 (https://www.ebay.com/usr/savvi.polyc?_trksid=p2060353.m2749.l2754)
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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.
+-RH
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Back in Summer 2015, I wanted something better for my aging +27 year old AM Carrier-Current gear, a Panaxis AM-100 exciter and a 2W home brew linear amp with a 7 element Chebychev. Looking at what that dude on PLL.gr had certainly fit the bill, http://www.pll.gr/product?pid=AM-20W (I was one of the last ones to get the unit with analog VU and SWR / RF OUT meters.) So, for $455.00USD's, I'd gotten an AM exciter with FREQ agile DDS oscillator, +24VDC - 6A power supply, 80W PEP amp, and an auto switching LPF board, with VSWR warning and RF fold-back protection. Beats paying Radio Systems for their $3,500.00 FCC certified TR-6000 10W AM exciter. However, I don't believe the amp is PWM, but a push-pull Class AB amp. Still, should last me for another +27 years, especially since I'm not running full bore 20W, but less than a 5W carrier to the CP-15 Radio Systems Carrier-Current coupler. Those Greeks seem to be kicking some RF butt on AM, and I'm glad to see that someone is.
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Maybe Al can have him build a custom gigawatt CB for him?
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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.
+-RH
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
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https://www.youtube.com/watch?v=JCNkDzlGLrg (https://www.youtube.com/watch?v=JCNkDzlGLrg)
https://www.youtube.com/watch?v=PTRtLAakezk (https://www.youtube.com/watch?v=PTRtLAakezk)
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funky beat yo