External Amplifier Legality Questions
Hello everyone, I have a question about FCC Rules regarding external amplifiers. I am considering re-purposing a wideband commercial amplifier for amateur use as a final stage for my ground station. The amplifier is capable of producing about 100W of power between 20 MHz and 500 MHz. I want to use this amp in conjunction with coax relays to switch between the 2m band and the 70cm band depending upon which spacecraft I'm operating.
My questions are as follows: Is it legal to use an amplifier designed for commercial applications in the Amateur Bands? This amplifier does not meet spurious signal suppression requirements, so I plan to use band specific filters after the amp to make sure I knock any spurs down below the required limits. Does the amplifier have to be type certified for use in the amateur bands?
As far as I can tell reading Part 97.315(subsection 3), The amplifier itself does not need to be type certified if: "(3)The amplifier is sold to an amateur radio operator or to a dealer, the amplifier is purchased in used condition by a dealer, /or the amplifier is sold to an amateur radio operator for use at that operator's station/. [emphasis added]"
I'm planning to use it in my amateur station so I don't think it has to be type certified. Am I missing something?
Also, The amplifier's 2nd Harmonic is about -30dBc down at 145 MHz. According to 97.307e: "The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30--225 MHz must be at least 60 dB below the mean power of the fundamental."
I'm planning to use a filter with about 40 dB of suppression at 290 MHz (2nd harmonic), so I get about -70 dB of suppression at the second harmonic, meeting the emission requirements of 97.307e.
I see no specific spurious signal suppression requirement for the 70cm band. The amplifier has similar 2nd Harmonic characteristics and I'm planning to use a similar filter for the 70cm band so the spurs should be down by about 70 dB of the fundamental mean power as well. The only wording I see that might apply is 97.307c: "All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice. "
I'm taking steps to eliminate interference by suppressing the 2nd Harmonic down about 70dB from the fundamental "in good engineering practice" so I think I meet all the requirements. Again, what am I missing?
I've heard of lots of hams re-purposing amplifiers for amateur use without legal concern, and I think this might be the case for my situation. I'd like some advice from those that may have gone down this road in the past. Any and all feedback from the group on this would be greatly appreciated. If I'm way off, please let me know.
Thanks in advance.
Sincerely, Zach, KJ4QLP
Hi ZAC
Seems you have the regs down well.
You modify it is like Home Brew, still must meet to meet FCC specifications.
The question is why do you need that much pwer for the satellittes?
You should keep your power down to a minim to communicate so you don't stress the birds.
100 watts with a 10dB gain is a lot of ERP!
R W4BUE
----- Original Message ----- From: "Zach Leffke" zleffke@vt.edu To: amsat-bb@amsat.org Sent: Wednesday, March 19, 2014 2:18 PM Subject: [amsat-bb] External Amplifier Legality Questions
Hello everyone, I have a question about FCC Rules regarding external amplifiers. I am considering re-purposing a wideband commercial amplifier for amateur use as a final stage for my ground station. The amplifier is capable of producing about 100W of power between 20 MHz and 500 MHz. I want to use this amp in conjunction with coax relays to switch between the 2m band and the 70cm band depending upon which spacecraft I'm operating.
My questions are as follows: Is it legal to use an amplifier designed for commercial applications in the Amateur Bands? This amplifier does not meet spurious signal suppression requirements, so I plan to use band specific filters after the amp to make sure I knock any spurs down below the required limits. Does the amplifier have to be type certified for use in the amateur bands?
As far as I can tell reading Part 97.315(subsection 3), The amplifier itself does not need to be type certified if: "(3)The amplifier is sold to an amateur radio operator or to a dealer, the amplifier is purchased in used condition by a dealer, /or the amplifier is sold to an amateur radio operator for use at that operator's station/. [emphasis added]"
I'm planning to use it in my amateur station so I don't think it has to be type certified. Am I missing something?
Also, The amplifier's 2nd Harmonic is about -30dBc down at 145 MHz. According to 97.307e: "The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30--225 MHz must be at least 60 dB below the mean power of the fundamental."
I'm planning to use a filter with about 40 dB of suppression at 290 MHz (2nd harmonic), so I get about -70 dB of suppression at the second harmonic, meeting the emission requirements of 97.307e.
I see no specific spurious signal suppression requirement for the 70cm band. The amplifier has similar 2nd Harmonic characteristics and I'm planning to use a similar filter for the 70cm band so the spurs should be down by about 70 dB of the fundamental mean power as well. The only wording I see that might apply is 97.307c: "All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice. "
I'm taking steps to eliminate interference by suppressing the 2nd Harmonic down about 70dB from the fundamental "in good engineering practice" so I think I meet all the requirements. Again, what am I missing?
I've heard of lots of hams re-purposing amplifiers for amateur use without legal concern, and I think this might be the case for my situation. I'd like some advice from those that may have gone down this road in the past. Any and all feedback from the group on this would be greatly appreciated. If I'm way off, please let me know.
Thanks in advance.
Sincerely, Zach, KJ4QLP
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I was going to follow up with my post. I see that Zach is involved in the Fox project and may be working on a command station. I can certainly see where he may want some extra power to ensure that commands get through.
But for operating - yes, you don't need a ton of EIRP. 100w is about the most as you need. On the transponders, any more just takes power away from other stations on the bird.
73,
Paul, N8HM
On Wed, Mar 19, 2014 at 3:10 PM, Rich/wa4bue richard.siff@verizon.net wrote:
Hi ZAC
Seems you have the regs down well.
You modify it is like Home Brew, still must meet to meet FCC specifications.
The question is why do you need that much pwer for the satellittes?
You should keep your power down to a minim to communicate so you don't stress the birds.
100 watts with a 10dB gain is a lot of ERP!
R W4BUE
----- Original Message ----- From: "Zach Leffke" zleffke@vt.edu To: amsat-bb@amsat.org Sent: Wednesday, March 19, 2014 2:18 PM Subject: [amsat-bb] External Amplifier Legality Questions
Hello everyone, I have a question about FCC Rules regarding external amplifiers. I am considering re-purposing a wideband commercial amplifier for amateur use as a final stage for my ground station. The amplifier is capable of producing about 100W of power between 20 MHz and 500 MHz. I want to use this amp in conjunction with coax relays to switch between the 2m band and the 70cm band depending upon which spacecraft I'm operating.
My questions are as follows: Is it legal to use an amplifier designed for commercial applications in the Amateur Bands? This amplifier does not meet spurious signal suppression requirements, so I plan to use band specific filters after the amp to make sure I knock any spurs down below the required limits. Does the amplifier have to be type certified for use in the amateur bands?
As far as I can tell reading Part 97.315(subsection 3), The amplifier itself does not need to be type certified if: "(3)The amplifier is sold to an amateur radio operator or to a dealer, the amplifier is purchased in used condition by a dealer, /or the amplifier is sold to an amateur radio operator for use at that operator's station/. [emphasis added]"
I'm planning to use it in my amateur station so I don't think it has to be type certified. Am I missing something?
Also, The amplifier's 2nd Harmonic is about -30dBc down at 145 MHz. According to 97.307e: "The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30--225 MHz must be at least 60 dB below the mean power of the fundamental."
I'm planning to use a filter with about 40 dB of suppression at 290 MHz (2nd harmonic), so I get about -70 dB of suppression at the second harmonic, meeting the emission requirements of 97.307e.
I see no specific spurious signal suppression requirement for the 70cm band. The amplifier has similar 2nd Harmonic characteristics and I'm planning to use a similar filter for the 70cm band so the spurs should be down by about 70 dB of the fundamental mean power as well. The only wording I see that might apply is 97.307c: "All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice. "
I'm taking steps to eliminate interference by suppressing the 2nd Harmonic down about 70dB from the fundamental "in good engineering practice" so I think I meet all the requirements. Again, what am I missing?
I've heard of lots of hams re-purposing amplifiers for amateur use without legal concern, and I think this might be the case for my situation. I'd like some advice from those that may have gone down this road in the past. Any and all feedback from the group on this would be greatly appreciated. If I'm way off, please let me know.
Thanks in advance.
Sincerely, Zach, KJ4QLP
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
My goal is to run a half watt into I what I hope will be some good antennas. We'll know something this spring. george wi9i
On Mar 19, 2014, at 2:10 PM, Rich/wa4bue wrote:
Hi ZAC
Seems you have the regs down well.
You modify it is like Home Brew, still must meet to meet FCC specifications.
The question is why do you need that much pwer for the satellittes?
You should keep your power down to a minim to communicate so you don't stress the birds.
100 watts with a 10dB gain is a lot of ERP!
R W4BUE
----- Original Message ----- From: "Zach Leffke" zleffke@vt.edu To: amsat-bb@amsat.org Sent: Wednesday, March 19, 2014 2:18 PM Subject: [amsat-bb] External Amplifier Legality Questions
Hello everyone, I have a question about FCC Rules regarding external amplifiers. I am considering re-purposing a wideband commercial amplifier for amateur use as a final stage for my ground station. The amplifier is capable of producing about 100W of power between 20 MHz and 500 MHz. I want to use this amp in conjunction with coax relays to switch between the 2m band and the 70cm band depending upon which spacecraft I'm operating.
My questions are as follows: Is it legal to use an amplifier designed for commercial applications in the Amateur Bands? This amplifier does not meet spurious signal suppression requirements, so I plan to use band specific filters after the amp to make sure I knock any spurs down below the required limits. Does the amplifier have to be type certified for use in the amateur bands?
As far as I can tell reading Part 97.315(subsection 3), The amplifier itself does not need to be type certified if: "(3)The amplifier is sold to an amateur radio operator or to a dealer, the amplifier is purchased in used condition by a dealer, /or the amplifier is sold to an amateur radio operator for use at that operator's station/. [emphasis added]"
I'm planning to use it in my amateur station so I don't think it has to be type certified. Am I missing something?
Also, The amplifier's 2nd Harmonic is about -30dBc down at 145 MHz. According to 97.307e: "The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30--225 MHz must be at least 60 dB below the mean power of the fundamental."
I'm planning to use a filter with about 40 dB of suppression at 290 MHz (2nd harmonic), so I get about -70 dB of suppression at the second harmonic, meeting the emission requirements of 97.307e.
I see no specific spurious signal suppression requirement for the 70cm band. The amplifier has similar 2nd Harmonic characteristics and I'm planning to use a similar filter for the 70cm band so the spurs should be down by about 70 dB of the fundamental mean power as well. The only wording I see that might apply is 97.307c: "All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice. "
I'm taking steps to eliminate interference by suppressing the 2nd Harmonic down about 70dB from the fundamental "in good engineering practice" so I think I meet all the requirements. Again, what am I missing?
I've heard of lots of hams re-purposing amplifiers for amateur use without legal concern, and I think this might be the case for my situation. I'd like some advice from those that may have gone down this road in the past. Any and all feedback from the group on this would be greatly appreciated. If I'm way off, please let me know.
Thanks in advance.
Sincerely, Zach, KJ4QLP
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi Zach,
What is the power output you have available from your transceiver and what type of antennas/coax do you plan to use.
In most cases, you need no more than 100W EIRP to operate through any LEO satellite. There are some rare exceptions where you might go a little beyond 100W EIRP, of course, but if you have a transceiver capable of putting out 20 watts and are feeding a moderate sized yagi with high-quality coax, you almost certainly don't need an amplifier.
You are correct that you may use that amplifier filtered as described, but depending on your situation, it may be best to put your money towards antennas and coax.
73,
Paul, N8HM
On Wed, Mar 19, 2014 at 2:18 PM, Zach Leffke zleffke@vt.edu wrote:
Hello everyone, I have a question about FCC Rules regarding external amplifiers. I am considering re-purposing a wideband commercial amplifier for amateur use as a final stage for my ground station. The amplifier is capable of producing about 100W of power between 20 MHz and 500 MHz. I want to use this amp in conjunction with coax relays to switch between the 2m band and the 70cm band depending upon which spacecraft I'm operating.
My questions are as follows: Is it legal to use an amplifier designed for commercial applications in the Amateur Bands? This amplifier does not meet spurious signal suppression requirements, so I plan to use band specific filters after the amp to make sure I knock any spurs down below the required limits. Does the amplifier have to be type certified for use in the amateur bands?
As far as I can tell reading Part 97.315(subsection 3), The amplifier itself does not need to be type certified if: "(3)The amplifier is sold to an amateur radio operator or to a dealer, the amplifier is purchased in used condition by a dealer, /or the amplifier is sold to an amateur radio operator for use at that operator's station/. [emphasis added]"
I'm planning to use it in my amateur station so I don't think it has to be type certified. Am I missing something?
Also, The amplifier's 2nd Harmonic is about -30dBc down at 145 MHz. According to 97.307e: "The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30--225 MHz must be at least 60 dB below the mean power of the fundamental."
I'm planning to use a filter with about 40 dB of suppression at 290 MHz (2nd harmonic), so I get about -70 dB of suppression at the second harmonic, meeting the emission requirements of 97.307e.
I see no specific spurious signal suppression requirement for the 70cm band. The amplifier has similar 2nd Harmonic characteristics and I'm planning to use a similar filter for the 70cm band so the spurs should be down by about 70 dB of the fundamental mean power as well. The only wording I see that might apply is 97.307c: "All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice. "
I'm taking steps to eliminate interference by suppressing the 2nd Harmonic down about 70dB from the fundamental "in good engineering practice" so I think I meet all the requirements. Again, what am I missing?
I've heard of lots of hams re-purposing amplifiers for amateur use without legal concern, and I think this might be the case for my situation. I'd like some advice from those that may have gone down this road in the past. Any and all feedback from the group on this would be greatly appreciated. If I'm way off, please let me know.
Thanks in advance.
Sincerely, Zach, KJ4QLP
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Amateur radio equipment does not have to be FCC type accepted but it must meet the requirements of Part 97. So you may repurpose your commercial amp for ham radio use as long as it meets the requirements of a "clean signal" and does not violate the power limitations of your license or the band.
Kevin Muenzler, WB5RUE Grid-EL09uf Eagle Creek Observatory http://www.eaglecreekobservatory.org I'd be unstoppable if it weren't for law enforcement and physics
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Zach Leffke Sent: Wednesday, March 19, 2014 1:19 PM To: amsat-bb@amsat.org Subject: [amsat-bb] External Amplifier Legality Questions
Hello everyone, I have a question about FCC Rules regarding external amplifiers. I am considering re-purposing a wideband commercial amplifier for amateur use as a final stage for my ground station. The amplifier is capable of producing about 100W of power between 20 MHz and 500 MHz. I want to use this amp in conjunction with coax relays to switch between the 2m band and the 70cm band depending upon which spacecraft I'm operating.
My questions are as follows: Is it legal to use an amplifier designed for commercial applications in the Amateur Bands? This amplifier does not meet spurious signal suppression requirements, so I plan to use band specific filters after the amp to make sure I knock any spurs down below the required limits. Does the amplifier have to be type certified for use in the amateur bands?
As far as I can tell reading Part 97.315(subsection 3), The amplifier itself does not need to be type certified if: "(3)The amplifier is sold to an amateur radio operator or to a dealer, the amplifier is purchased in used condition by a dealer, /or the amplifier is sold to an amateur radio operator for use at that operator's station/. [emphasis added]"
I'm planning to use it in my amateur station so I don't think it has to be type certified. Am I missing something?
Also, The amplifier's 2nd Harmonic is about -30dBc down at 145 MHz. According to 97.307e: "The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30--225 MHz must be at least 60 dB below the mean power of the fundamental."
I'm planning to use a filter with about 40 dB of suppression at 290 MHz (2nd harmonic), so I get about -70 dB of suppression at the second harmonic, meeting the emission requirements of 97.307e.
I see no specific spurious signal suppression requirement for the 70cm band. The amplifier has similar 2nd Harmonic characteristics and I'm planning to use a similar filter for the 70cm band so the spurs should be down by about 70 dB of the fundamental mean power as well. The only wording I see that might apply is 97.307c: "All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice. "
I'm taking steps to eliminate interference by suppressing the 2nd Harmonic down about 70dB from the fundamental "in good engineering practice" so I think I meet all the requirements. Again, what am I missing?
I've heard of lots of hams re-purposing amplifiers for amateur use without legal concern, and I think this might be the case for my situation. I'd like some advice from those that may have gone down this road in the past. Any and all feedback from the group on this would be greatly appreciated. If I'm way off, please let me know.
Thanks in advance.
Sincerely, Zach, KJ4QLP
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi Zach...
Amateurs have worked very hard to remain responsible for their own emissions.
The need for 100 watts for your application aside, you can use any transmitter/amplifier you want as long as it's output is under the maximum limit for the band and your license.
However...you are PERSONALLY responsible for your signal, it's spurs, harmonics and any other junk it causes.
It sounds like you have everything well researched as to how to engineer it to your needs and signal requirements.
That's why we have licenses...to show the world that we are capable of being responsible for our own designs and protecting our service.
We do not want to go down the path of type acceptance for re-purposed electronics.
Enjoy your experimenting but listen to the experienced.
Roger WA1KAT (First 145 mcs rig was a SCR-522 AND yes I did try to run a TBS)
On 3/19/2014 2:18 PM, Zach Leffke wrote:
Hello everyone, I have a question about FCC Rules regarding external amplifiers. I am considering re-purposing a wideband commercial amplifier for amateur use as a final stage for my ground station. The amplifier is capable of producing about 100W of power between 20 MHz and 500 MHz. I want to use this amp in conjunction with coax relays to switch between the 2m band and the 70cm band depending upon which spacecraft I'm operating.
My questions are as follows: Is it legal to use an amplifier designed for commercial applications in the Amateur Bands? This amplifier does not meet spurious signal suppression requirements, so I plan to use band specific filters after the amp to make sure I knock any spurs down below the required limits. Does the amplifier have to be type certified for use in the amateur bands?
participants (6)
-
george hinkle -
Kevin Muenzler, WB5RUE -
Paul Stoetzer -
Rich/wa4bue -
Roger Kolakowski -
Zach Leffke