Re: [AFMUG] How to count amplifiers in link budget
I have heard tales of cyrogenic LNA with NF below 1 dB. -Original Message- From: Brian Webster Sent: Thursday, July 12, 2018 5:43 PM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] How to count amplifiers in link budget Also keep in mind in the cellular world they used diversity antennas and pre-amps to make up for the lower return path power budget. Their radios have separate transmit and receive ports and antenna systems, they are not locked in to the one antenna half duplex mentality. Having a separate receive antenna or array that offers more gain than on the transmit side has worked for many years in that space. In the early cellular days when capacity and spectrum reuse was not an issue, it was common deployment practice to have both an Omni for the tower side to transmit and sectors with higher gain for receive to try and balance out the power budgets from the mobile units. The radios at the tower sites had separate ports for TX and RX. Thank You, Brian Webster www.wirelessmapping.com www.Broadband-Mapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Adam Moffett Sent: Thursday, July 12, 2018 4:00 PM To: af@af.afmug.com Subject: Re: [AFMUG] How to count amplifiers in link budget Good to know. On 7/12/2018 3:30 PM, ch...@wbmfg.com wrote: 3dB NF is nothing to crow about these days. Lots of front ends and preamps are below 2 dB. Even 1.5 is common. -Original Message- From: Adam Moffett Sent: Thursday, July 12, 2018 1:24 PM To: af@af.afmug.com Subject: Re: [AFMUG] How to count amplifiers in link budget Understood. This is 700mhz A-Block, so I'm allowed 1000W ERP in one direction and 30W ERP in the other. I hadn't thought it through yet when I talked about amping the 30W side. My thinking was to use the higher power channel for downlink. I'm looking at setting Tx power to +24, adding an amp which says +22 on the spec sheet, and a 10db omni. That puts me around 400W before cable losses, might be 300W after cables and connectors depending on the specifics. The spec sheet claims a noise figure of "<3db", and that seems reasonable as long as it's not a lie. In this configuration the uplink might be up to 12db weaker than the downlink, but if I have the maximum modulation level down, then I'll still have something acceptable up. Something like 500kbps x 200kbps in a 250khz channel. -Adam On 7/12/2018 2:57 PM, Brian Webster wrote: Remembering also that you will likely need a balanced path so if both ends of the link don't have the amplification you may have a problem. Amps with a preamplifier also included have noise figures that don't always give you a realized gain on the receive side. Using antenna gain over just amplification to reach the max legal power is always preferable if possible as the gain benefits you on both receive and transmit. Thank You, Brian Webster Skype: Radiowebst www.wirelessmapping.com www.Broadband-Mapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Robert Andrews Sent: Thursday, July 12, 2018 2:16 PM To: af@af.afmug.com Subject: Re: [AFMUG] How to count amplifiers in link budget But he said he gets 30 ERP not 30 EIRP where EIRP = 1.64 * ERP ( if he is actually allowed 30 ERP and not 30 EIRP ). So that would be 49.2 EIRP IF he is allowed 30 _ERP_.. so 49.2. watts would be another 2.15 db.. 9.85 dbm gain antenna. Still no need for an amp... Please check my math and assumptions, as I _always_ stick my hand up in class and then spit out the wrong answer... On 07/12/2018 10:30 AM, ch...@wbmfg.com wrote: Yep, that is how you do it. 30 watts EIRP is 44.7 dBm 5 watts is 37 dBm. So 44.7 - 37 = 7.7 dB gain. A 7.7 dBi antenna is pretty common. After adding antenna gain, I don't see much room to amplify. -Original Message- From: Adam Moffett Sent: Thursday, July 12, 2018 11:06 AM To: af@af.afmug.com Subject: [AFMUG] How to count amplifiers in link budget I'm looking at an IoT application where we're allowed 30W ERP. The transmitter is 5W, so even with antenna gain I have room to amplify that. How do you count an amplifier in your link budget? Just add the amp's tx gain and subtract connectors, or is there more to it than that? Strangely I've never used an amplifier.I've never had a legal application for one before. -Adam -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
Also keep in mind in the cellular world they used diversity antennas and pre-amps to make up for the lower return path power budget. Their radios have separate transmit and receive ports and antenna systems, they are not locked in to the one antenna half duplex mentality. Having a separate receive antenna or array that offers more gain than on the transmit side has worked for many years in that space. In the early cellular days when capacity and spectrum reuse was not an issue, it was common deployment practice to have both an Omni for the tower side to transmit and sectors with higher gain for receive to try and balance out the power budgets from the mobile units. The radios at the tower sites had separate ports for TX and RX. Thank You, Brian Webster www.wirelessmapping.com www.Broadband-Mapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Adam Moffett Sent: Thursday, July 12, 2018 4:00 PM To: af@af.afmug.com Subject: Re: [AFMUG] How to count amplifiers in link budget Good to know. On 7/12/2018 3:30 PM, ch...@wbmfg.com wrote: > 3dB NF is nothing to crow about these days. Lots of front ends and > preamps are below 2 dB. Even 1.5 is common. > > -Original Message- From: Adam Moffett > Sent: Thursday, July 12, 2018 1:24 PM > To: af@af.afmug.com > Subject: Re: [AFMUG] How to count amplifiers in link budget > > Understood. This is 700mhz A-Block, so I'm allowed 1000W ERP in one > direction and 30W ERP in the other. I hadn't thought it through yet > when I talked about amping the 30W side. > > My thinking was to use the higher power channel for downlink. I'm > looking at setting Tx power to +24, adding an amp which says +22 on the > spec sheet, and a 10db omni. That puts me around 400W before cable > losses, might be 300W after cables and connectors depending on the > specifics. The spec sheet claims a noise figure of "<3db", and that > seems reasonable as long as it's not a lie. > > In this configuration the uplink might be up to 12db weaker than the > downlink, but if I have the maximum modulation level down, then I'll > still have something acceptable up. Something like 500kbps x 200kbps > in a 250khz channel. > > -Adam > > > On 7/12/2018 2:57 PM, Brian Webster wrote: >> Remembering also that you will likely need a balanced path so if both >> ends >> of the link don't have the amplification you may have a problem. Amps >> with a >> preamplifier also included have noise figures that don't always give >> you a >> realized gain on the receive side. Using antenna gain over just >> amplification to reach the max legal power is always preferable if >> possible >> as the gain benefits you on both receive and transmit. >> >> Thank You, >> Brian Webster >> Skype: Radiowebst >> www.wirelessmapping.com >> www.Broadband-Mapping.com >> >> -Original Message- >> From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Robert Andrews >> Sent: Thursday, July 12, 2018 2:16 PM >> To: af@af.afmug.com >> Subject: Re: [AFMUG] How to count amplifiers in link budget >> >> But he said he gets 30 ERP not 30 EIRP where EIRP = 1.64 * ERP ( if he >> is actually allowed 30 ERP and not 30 EIRP ). So that would be 49.2 >> EIRP IF he is allowed 30 _ERP_.. so 49.2. watts would be another 2.15 >> db.. 9.85 dbm gain antenna. Still no need for an amp... >> >> Please check my math and assumptions, as I _always_ stick my hand up in >> class and then spit out the wrong answer... >> >> On 07/12/2018 10:30 AM, ch...@wbmfg.com wrote: >>> Yep, that is how you do it. 30 watts EIRP is 44.7 dBm >>> 5 watts is 37 dBm. So 44.7 - 37 = 7.7 dB gain. >>> >>> A 7.7 dBi antenna is pretty common. >>> After adding antenna gain, I don't see much room to amplify. >>> -Original Message- From: Adam Moffett Sent: Thursday, July 12, >>> 2018 11:06 AM To: af@af.afmug.com Subject: [AFMUG] How to count >>> amplifiers in link budget >>> I'm looking at an IoT application where we're allowed 30W ERP. The >>> transmitter is 5W, so even with antenna gain I have room to amplify >>> that. >>> >>> How do you count an amplifier in your link budget? Just add the amp's >>> tx gain and subtract connectors, or is there more to it than that? >>> >>> Strangely I've never used an amplifier.I've never had a legal >>> application for one before. >>> >>> -Adam >>> >>> > > -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
Good to know. On 7/12/2018 3:30 PM, ch...@wbmfg.com wrote: 3dB NF is nothing to crow about these days. Lots of front ends and preamps are below 2 dB. Even 1.5 is common. -Original Message- From: Adam Moffett Sent: Thursday, July 12, 2018 1:24 PM To: af@af.afmug.com Subject: Re: [AFMUG] How to count amplifiers in link budget Understood. This is 700mhz A-Block, so I'm allowed 1000W ERP in one direction and 30W ERP in the other. I hadn't thought it through yet when I talked about amping the 30W side. My thinking was to use the higher power channel for downlink. I'm looking at setting Tx power to +24, adding an amp which says +22 on the spec sheet, and a 10db omni. That puts me around 400W before cable losses, might be 300W after cables and connectors depending on the specifics. The spec sheet claims a noise figure of "<3db", and that seems reasonable as long as it's not a lie. In this configuration the uplink might be up to 12db weaker than the downlink, but if I have the maximum modulation level down, then I'll still have something acceptable up. Something like 500kbps x 200kbps in a 250khz channel. -Adam On 7/12/2018 2:57 PM, Brian Webster wrote: Remembering also that you will likely need a balanced path so if both ends of the link don't have the amplification you may have a problem. Amps with a preamplifier also included have noise figures that don't always give you a realized gain on the receive side. Using antenna gain over just amplification to reach the max legal power is always preferable if possible as the gain benefits you on both receive and transmit. Thank You, Brian Webster Skype: Radiowebst www.wirelessmapping.com www.Broadband-Mapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Robert Andrews Sent: Thursday, July 12, 2018 2:16 PM To: af@af.afmug.com Subject: Re: [AFMUG] How to count amplifiers in link budget But he said he gets 30 ERP not 30 EIRP where EIRP = 1.64 * ERP ( if he is actually allowed 30 ERP and not 30 EIRP ). So that would be 49.2 EIRP IF he is allowed 30 _ERP_.. so 49.2. watts would be another 2.15 db.. 9.85 dbm gain antenna. Still no need for an amp... Please check my math and assumptions, as I _always_ stick my hand up in class and then spit out the wrong answer... On 07/12/2018 10:30 AM, ch...@wbmfg.com wrote: Yep, that is how you do it. 30 watts EIRP is 44.7 dBm 5 watts is 37 dBm. So 44.7 - 37 = 7.7 dB gain. A 7.7 dBi antenna is pretty common. After adding antenna gain, I don't see much room to amplify. -Original Message- From: Adam Moffett Sent: Thursday, July 12, 2018 11:06 AM To: af@af.afmug.com Subject: [AFMUG] How to count amplifiers in link budget I'm looking at an IoT application where we're allowed 30W ERP. The transmitter is 5W, so even with antenna gain I have room to amplify that. How do you count an amplifier in your link budget? Just add the amp's tx gain and subtract connectors, or is there more to it than that? Strangely I've never used an amplifier.I've never had a legal application for one before. -Adam -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
Understood. This is 700mhz A-Block, so I'm allowed 1000W ERP in one direction and 30W ERP in the other. I hadn't thought it through yet when I talked about amping the 30W side. My thinking was to use the higher power channel for downlink. I'm looking at setting Tx power to +24, adding an amp which says +22 on the spec sheet, and a 10db omni. That puts me around 400W before cable losses, might be 300W after cables and connectors depending on the specifics. The spec sheet claims a noise figure of "<3db", and that seems reasonable as long as it's not a lie. In this configuration the uplink might be up to 12db weaker than the downlink, but if I have the maximum modulation level down, then I'll still have something acceptable up. Something like 500kbps x 200kbps in a 250khz channel. -Adam On 7/12/2018 2:57 PM, Brian Webster wrote: Remembering also that you will likely need a balanced path so if both ends of the link don't have the amplification you may have a problem. Amps with a preamplifier also included have noise figures that don't always give you a realized gain on the receive side. Using antenna gain over just amplification to reach the max legal power is always preferable if possible as the gain benefits you on both receive and transmit. Thank You, Brian Webster Skype: Radiowebst www.wirelessmapping.com www.Broadband-Mapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Robert Andrews Sent: Thursday, July 12, 2018 2:16 PM To: af@af.afmug.com Subject: Re: [AFMUG] How to count amplifiers in link budget But he said he gets 30 ERP not 30 EIRP where EIRP = 1.64 * ERP ( if he is actually allowed 30 ERP and not 30 EIRP ). So that would be 49.2 EIRP IF he is allowed 30 _ERP_.. so 49.2. watts would be another 2.15 db.. 9.85 dbm gain antenna. Still no need for an amp... Please check my math and assumptions, as I _always_ stick my hand up in class and then spit out the wrong answer... On 07/12/2018 10:30 AM, ch...@wbmfg.com wrote: Yep, that is how you do it. 30 watts EIRP is 44.7 dBm 5 watts is 37 dBm. So 44.7 - 37 = 7.7 dB gain. A 7.7 dBi antenna is pretty common. After adding antenna gain, I don't see much room to amplify. -Original Message- From: Adam Moffett Sent: Thursday, July 12, 2018 11:06 AM To: af@af.afmug.com Subject: [AFMUG] How to count amplifiers in link budget I'm looking at an IoT application where we're allowed 30W ERP. The transmitter is 5W, so even with antenna gain I have room to amplify that. How do you count an amplifier in your link budget? Just add the amp's tx gain and subtract connectors, or is there more to it than that? Strangely I've never used an amplifier.I've never had a legal application for one before. -Adam -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
Remembering also that you will likely need a balanced path so if both ends of the link don't have the amplification you may have a problem. Amps with a preamplifier also included have noise figures that don't always give you a realized gain on the receive side. Using antenna gain over just amplification to reach the max legal power is always preferable if possible as the gain benefits you on both receive and transmit. Thank You, Brian Webster Skype: Radiowebst www.wirelessmapping.com www.Broadband-Mapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Robert Andrews Sent: Thursday, July 12, 2018 2:16 PM To: af@af.afmug.com Subject: Re: [AFMUG] How to count amplifiers in link budget But he said he gets 30 ERP not 30 EIRP where EIRP = 1.64 * ERP ( if he is actually allowed 30 ERP and not 30 EIRP ). So that would be 49.2 EIRP IF he is allowed 30 _ERP_.. so 49.2. watts would be another 2.15 db.. 9.85 dbm gain antenna. Still no need for an amp... Please check my math and assumptions, as I _always_ stick my hand up in class and then spit out the wrong answer... On 07/12/2018 10:30 AM, ch...@wbmfg.com wrote: > Yep, that is how you do it. 30 watts EIRP is 44.7 dBm > 5 watts is 37 dBm. So 44.7 - 37 = 7.7 dB gain. > > A 7.7 dBi antenna is pretty common. > After adding antenna gain, I don't see much room to amplify. > -Original Message- From: Adam Moffett Sent: Thursday, July 12, > 2018 11:06 AM To: af@af.afmug.com Subject: [AFMUG] How to count > amplifiers in link budget > I'm looking at an IoT application where we're allowed 30W ERP. The > transmitter is 5W, so even with antenna gain I have room to amplify that. > > How do you count an amplifier in your link budget? Just add the amp's > tx gain and subtract connectors, or is there more to it than that? > > Strangely I've never used an amplifier.I've never had a legal > application for one before. > > -Adam > > -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
Yeah, I actually have 1000W ERP, my mistake. On 7/12/2018 2:16 PM, Robert Andrews wrote: But he said he gets 30 ERP not 30 EIRP where EIRP = 1.64 * ERP ( if he is actually allowed 30 ERP and not 30 EIRP ). So that would be 49.2 EIRP IF he is allowed 30 _ERP_.. so 49.2. watts would be another 2.15 db.. 9.85 dbm gain antenna. Still no need for an amp... Please check my math and assumptions, as I _always_ stick my hand up in class and then spit out the wrong answer... On 07/12/2018 10:30 AM, ch...@wbmfg.com wrote: Yep, that is how you do it. 30 watts EIRP is 44.7 dBm 5 watts is 37 dBm. So 44.7 - 37 = 7.7 dB gain. A 7.7 dBi antenna is pretty common. After adding antenna gain, I don't see much room to amplify. -Original Message- From: Adam Moffett Sent: Thursday, July 12, 2018 11:06 AM To: af@af.afmug.com Subject: [AFMUG] How to count amplifiers in link budget I'm looking at an IoT application where we're allowed 30W ERP. The transmitter is 5W, so even with antenna gain I have room to amplify that. How do you count an amplifier in your link budget? Just add the amp's tx gain and subtract connectors, or is there more to it than that? Strangely I've never used an amplifier.I've never had a legal application for one before. -Adam -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
But he said he gets 30 ERP not 30 EIRP where EIRP = 1.64 * ERP ( if he is actually allowed 30 ERP and not 30 EIRP ). So that would be 49.2 EIRP IF he is allowed 30 _ERP_.. so 49.2. watts would be another 2.15 db.. 9.85 dbm gain antenna. Still no need for an amp... Please check my math and assumptions, as I _always_ stick my hand up in class and then spit out the wrong answer... On 07/12/2018 10:30 AM, ch...@wbmfg.com wrote: Yep, that is how you do it. 30 watts EIRP is 44.7 dBm 5 watts is 37 dBm. So 44.7 - 37 = 7.7 dB gain. A 7.7 dBi antenna is pretty common. After adding antenna gain, I don't see much room to amplify. -Original Message- From: Adam Moffett Sent: Thursday, July 12, 2018 11:06 AM To: af@af.afmug.com Subject: [AFMUG] How to count amplifiers in link budget I'm looking at an IoT application where we're allowed 30W ERP. The transmitter is 5W, so even with antenna gain I have room to amplify that. How do you count an amplifier in your link budget? Just add the amp's tx gain and subtract connectors, or is there more to it than that? Strangely I've never used an amplifier.I've never had a legal application for one before. -Adam -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
I read that as the 5w was with antenna. Chuck is correct. 7dbm antenna and you are good to go. On Thu, Jul 12, 2018 at 10:33 AM Jason Wilson wrote: > 44dbm is your target. You are at 37dbm now. 8dbm amplifier should take > care of any cable loss. > > On Thu, Jul 12, 2018 at 10:08 AM Adam Moffett wrote: > >> I'm looking at an IoT application where we're allowed 30W ERP. The >> transmitter is 5W, so even with antenna gain I have room to amplify that. >> >> How do you count an amplifier in your link budget? Just add the amp's >> tx gain and subtract connectors, or is there more to it than that? >> >> Strangely I've never used an amplifier.I've never had a legal >> application for one before. >> >> -Adam >> >> >> -- >> AF mailing list >> AF@af.afmug.com >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> > -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
44dbm is your target. You are at 37dbm now. 8dbm amplifier should take care of any cable loss. On Thu, Jul 12, 2018 at 10:08 AM Adam Moffett wrote: > I'm looking at an IoT application where we're allowed 30W ERP. The > transmitter is 5W, so even with antenna gain I have room to amplify that. > > How do you count an amplifier in your link budget? Just add the amp's > tx gain and subtract connectors, or is there more to it than that? > > Strangely I've never used an amplifier.I've never had a legal > application for one before. > > -Adam > > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] How to count amplifiers in link budget
Yep, that is how you do it. 30 watts EIRP is 44.7 dBm 5 watts is 37 dBm. So 44.7 - 37 = 7.7 dB gain. A 7.7 dBi antenna is pretty common. After adding antenna gain, I don't see much room to amplify. -Original Message- From: Adam Moffett Sent: Thursday, July 12, 2018 11:06 AM To: af@af.afmug.com Subject: [AFMUG] How to count amplifiers in link budget I'm looking at an IoT application where we're allowed 30W ERP. The transmitter is 5W, so even with antenna gain I have room to amplify that. How do you count an amplifier in your link budget? Just add the amp's tx gain and subtract connectors, or is there more to it than that? Strangely I've never used an amplifier.I've never had a legal application for one before. -Adam -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
