61
Part 15 AM and FM Station Operation / Re: Introducing Parking Lot Radio!
« on: September 30, 2022, 1852 UTC »
Yes. Getting a transmitter tested for FCC approval can run into the 5 figure category.
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Shortwave Pirate Radio In North America And Around The World, And Other Signals That Go Bump In The Night
We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations.
Always consult with the appropriate authorities if you have questions concerning what is permissible in your locale.
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62
Huh? / Re: Huge flaw” threatens US emergency alert system, DHS researcher warns!
« on: September 13, 2022, 1930 UTC »
I don't know how "huge" this is. The encoder with the vulnerability is a low-end encoder bought by folks that were too cheap to buy a Sage, and probably don't check their logs anyway. I believe that the commission revoked the type acceptance to those units years ago, deeming them illegal to use in a FCC licensed station in the first place.
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63
Huh? / Re: Expansion of FM Band, a.k.a. Wide-FM, 76-88MHz, back in the news.
« on: September 13, 2022, 1924 UTC »
If we're going to go that far, might as well resurrect OIRT's polar FM as well...
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64
General Radio Discussion / Re: Tour of AM Stereo Station KYET
« on: September 10, 2022, 2317 UTC »
There isn't a lot of CMOS in those cards. Most of it was MC series stuff from the 80's, the rest being discrete TTL stuff.
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65
HF Mystery Signals / Re: 5 kHz bursts, 9 times per 10s, all over HF, deviating ±5 kHz around center freq
« on: August 28, 2022, 0612 UTC »
Another clue is that it occurs day and night. Signals propagating from afar will not behave in such ways, especially across the HF spectrum.
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66
Huh? / Re: Compromís asks to end FM radio to save energy?
« on: August 13, 2022, 1757 UTC »
I'd love to see the twisted math it took to say that digital modes of transmission use less power. To this day, the best linear TV technology is 45% DC to RF efficiency. Analog FM is near 80%, AM is over 90%.
This perversion of 'save the planet' justifying ever encroaching authoritarianism needs to stop, and people need to put their foot down.
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This perversion of 'save the planet' justifying ever encroaching authoritarianism needs to stop, and people need to put their foot down.
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67
Part 15 AM and FM Station Operation / Re: Coax to use
« on: August 06, 2022, 0613 UTC »
I've used the off brand lmr cable with good results. I've been using off brand half inch super flex on projects lately also without incident.
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68
Part 15 AM and FM Station Operation / Re: Coax to use
« on: August 03, 2022, 0653 UTC »
Agreed. For runs under 50 feet, lmr240 is fine. I use it for short cellular jumpers without issue. Anything longer though, I'd use lmr400.
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69
Part 15 AM and FM Station Operation / Re: New $69 laptop good for Ham (or solar Part15
« on: July 25, 2022, 1816 UTC »
Nothing new under the sun. I had an old net-top laptop about a decade ago I bought for the same purpose. It wound up being a surfing laptop for the garage and the tub.
I'm sure it's arm based to run that low on the consumption end, so don't expect a speed demon.
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I'm sure it's arm based to run that low on the consumption end, so don't expect a speed demon.
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70
The RF Workbench / Re: Beyond 45/48m
« on: June 14, 2022, 0247 UTC »
Your not reading again stretchy. I am talking about 1700v devices with 80mOhm RDSon...not 900v devices at 280mOhm.
The current rig has run up to 10 Mhz. I have little interest in anything much above that as I don't operate during the day. Bolt on fet drivers are used to deal with the gate capacity. I will explore GaN when the price performance ratio gets more attractive. For now Sic makes more sense in my topologies and power levels. If they come out with comparable high voltage GaN devices at a reasonable price, I'll consider it.
I like my current approach as it affords high power with a simple low cost PA architecture. There are ways to get similar power with lower voltages, but circuit complexity, the headache of ferrite, high current losses, etc start to make things unnatractive for my needs.
SiC devices have made what I'm doing possible at much lower cost, and simpler design than was possible just a handful of years ago. GaN for the moment, does not hold the same advantages.
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The current rig has run up to 10 Mhz. I have little interest in anything much above that as I don't operate during the day. Bolt on fet drivers are used to deal with the gate capacity. I will explore GaN when the price performance ratio gets more attractive. For now Sic makes more sense in my topologies and power levels. If they come out with comparable high voltage GaN devices at a reasonable price, I'll consider it.
I like my current approach as it affords high power with a simple low cost PA architecture. There are ways to get similar power with lower voltages, but circuit complexity, the headache of ferrite, high current losses, etc start to make things unnatractive for my needs.
SiC devices have made what I'm doing possible at much lower cost, and simpler design than was possible just a handful of years ago. GaN for the moment, does not hold the same advantages.
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72
The RF Workbench / Re: Beyond 45/48m
« on: June 11, 2022, 0507 UTC »
The current transmitter has C2M0080120D's in it I believe. Mouser has them in stock again, but the price has gone up. Microsemi/Microchip have comparable ones are a little cheaper (half) and have lower gate capacity. I have not tried them in a circuit though.
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73
The RF Workbench / Re: Wanna' communicate, and broadcast, with light? It can be done!
« on: June 11, 2022, 0431 UTC »
Complements of Max M Carter, who has a cool radio hobby website as well;
Music on a light beam http://maxmcarter.com/lasrstuf/laserexperiments.html
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Music on a light beam http://maxmcarter.com/lasrstuf/laserexperiments.html
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74
The RF Workbench / Re: Beyond 45/48m
« on: June 10, 2022, 0339 UTC »
In the modern era of 56V power tools, higher voltage operation is no longer a challenge. My Ego trimmer has enough battery on it to run a 50 watt transmitter for over two hours, and recharges in 15 minutes!
I too have had reasonable success with CMCD since 2017 and have been running with Cree 1200V devices. They have even survived a few moments of stupidity with VSWR easily over 2:1 at rated power. I am now eying Microsemi as they have 1700V devices at reasonable cost, and in stock. This should facilitate 2KW carrier or greater in one PA with two devices. Time will tell, as prototypes are in the works.
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I too have had reasonable success with CMCD since 2017 and have been running with Cree 1200V devices. They have even survived a few moments of stupidity with VSWR easily over 2:1 at rated power. I am now eying Microsemi as they have 1700V devices at reasonable cost, and in stock. This should facilitate 2KW carrier or greater in one PA with two devices. Time will tell, as prototypes are in the works.
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75
