Re: [Elecraft] KPA500 active devices!!
The fcc requires amplifier gain to be 15 decibels maximum for any amatuer radio amplifier. What a stupid regulation! On the one hand you are allowed 1500W and on the other only 15dB gain? It makes no sense. Presumably one of the CB regulations. A gain of 15 dB is reasonable for a single stage FET amplifier I agree. Does the FCC also forbid operating amplifiers in series? Mike -- View this message in context: http://n2.nabble.com/News-from-Visalia-tp4914396p4930822.html Sent from the [QRO] mailing list archive at Nabble.com. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
The VRF2933 is rated 3:1 Load VSWR Capability at Specifi ed Operating Conditions according to its datasheet; perhaps that's why there no built-in ATU. .but that doesn't mean SSB IMD would be acceptable, or it would be safe in every circuit at that mismatch, so keep that in mind. :-) No matter what the data sheets say about device life, the PA often needs to be kept within 1.5:1 or better SWR to meet IMD specs. 3:1 is a huge loadline move, depending on the direction of the impedance move it could really put the PA into severe flattopping. Use a tuner or fix the antenna, be safe. 73 Tom On Sat, Apr 17, 2010 at 6:44 PM, Doug Faunt N6TQS +1-510-655-8604 fa...@panix.com wrote: There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: A known bad url was replaced by VIPRE Please help support this email list: A known bad url was replaced by VIPRE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: A known bad url was replaced by VIPRE Please help support this email list: A known bad url was replaced by VIPRE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
Well said tom, an often overlooked aspect is the angle of the mismatch, load pull is the only way to tell, while a 3:1 resitive is not to harsh, very few things will survive a 3:1 at an inductive reactance angle. Load pull is the only way to be sure, and I would be uncomfortable making any claims until such a test has been done. Matt W8ESE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
Device web site was claiming any angle in the device specs. (!!!???) This should be fun to watch. 73, Guy. On Sun, Apr 18, 2010 at 9:54 AM, Matt Palmer kd8...@gmail.com wrote: Well said tom, an often overlooked aspect is the angle of the mismatch, load pull is the only way to tell, while a 3:1 resitive is not to harsh, very few things will survive a 3:1 at an inductive reactance angle. Load pull is the only way to be sure, and I would be uncomfortable making any claims until such a test has been done. Matt W8ESE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
It's pretty basic stuff Guy. Look at what happens in this MRF150: http://www.w8ji.com/demonstation.htm It would be nice if there was a free lunch and we could magically buy a device that didn't care about the load and gave reasonable operating efficiency and good IMD with any impedance from perfect to a 3:1 mismatch, but it isn't possible. Not blowing up in a few seconds on a data sheet test circuit is a whole lot different than being acceptable to operate that way in the real world. 73 Tom Device web site was claiming any angle in the device specs. (!!!???) This should be fun to watch. 73, Guy. On Sun, Apr 18, 2010 at 9:54 AM, Matt Palmer kd8...@gmail.com wrote: Well said tom, an often overlooked aspect is the angle of the mismatch, load pull is the only way to tell, while a 3:1 resitive is not to harsh, very few things will survive a 3:1 at an inductive reactance angle. Load pull is the only way to be sure, and I would be uncomfortable making any claims until such a test has been done. Matt W8ESE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: A known bad url was replaced by VIPRE Please help support this email list: A known bad url was replaced by VIPRE __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
The fcc requires amplifier gain to be 15 decibels maximum for any amatuer radio amplifier. In reality, with negative feedback applied to level PA gain, the required drive to reach 500W is closer to 30 W here. Eric _..._ Joe Subich, W4TV li...@subich.com wrote: The VRF2933 is rated for 300 Watts each according to the data sheet on the manufacturer's web site (Microsemi) ... That makes their use in a 500 W amplifier reasonable from an IMD perspective. The VRF 2933 minimum gain is also 20dB (23 dB typical) so it would appear that the KPA-500 should be capable of clean operation with 5 W of drive (e.g., K3 in low power mode). 73, ... Joe, W4TV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Doug Faunt N6TQS +1-510-655-8604 Sent: Saturday, April 17, 2010 6:45 PM To: elecraft@mailman.qth.net Subject: [Elecraft] KPA500 active devices!! There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] KPA500 active devices!!
There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
The VRF2933 is rated 3:1 Load VSWR Capability at Specifi ed Operating Conditions according to its datasheet; perhaps that's why there no built-in ATU. On Sat, Apr 17, 2010 at 6:44 PM, Doug Faunt N6TQS +1-510-655-8604 fa...@panix.com wrote: There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
At any phase angle with no signal degradation. Minimum 20 dB gain, 300 watt output 400 typical per device. So being operated very conservatively. On Sat, Apr 17, 2010 at 7:22 PM, S Sacco nn4x.st...@gmail.com wrote: The VRF2933 is rated 3:1 Load VSWR Capability at Specifi ed Operating Conditions according to its datasheet; perhaps that's why there no built-in ATU. On Sat, Apr 17, 2010 at 6:44 PM, Doug Faunt N6TQS +1-510-655-8604 fa...@panix.com wrote: There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
Hi All' Works for me..Bring it on Elecraft...!!! Gary On Sun, Apr 18, 2010 at 9:30 AM, Guy Olinger K2AV olin...@bellsouth.netwrote: At any phase angle with no signal degradation. Minimum 20 dB gain, 300 watt output 400 typical per device. So being operated very conservatively. On Sat, Apr 17, 2010 at 7:22 PM, S Sacco nn4x.st...@gmail.com wrote: The VRF2933 is rated 3:1 Load VSWR Capability at Specifi ed Operating Conditions according to its datasheet; perhaps that's why there no built-in ATU. On Sat, Apr 17, 2010 at 6:44 PM, Doug Faunt N6TQS +1-510-655-8604 fa...@panix.com wrote: There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html -- Gary VK4FD - Motorhome Mobile http://www.qsl.net/vk4fd/ K3 #679 For everything else there's Mastercard!!! __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
Just for curiosity, what do a pair of VRF2933 cost? Availability? 73 de Brian/K3KO Guy Olinger K2AV wrote: At any phase angle with no signal degradation. Minimum 20 dB gain, 300 watt output 400 typical per device. So being operated very conservatively. On Sat, Apr 17, 2010 at 7:22 PM, S Sacco nn4x.st...@gmail.com wrote: The VRF2933 is rated 3:1 Load VSWR Capability at Specifi ed Operating Conditions according to its datasheet; perhaps that's why there no built-in ATU. On Sat, Apr 17, 2010 at 6:44 PM, Doug Faunt N6TQS +1-510-655-8604 fa...@panix.com wrote: There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
The VRF2933 is rated for 300 Watts each according to the data sheet on the manufacturer's web site (Microsemi) ... That makes their use in a 500 W amplifier reasonable from an IMD perspective. The VRF 2933 minimum gain is also 20dB (23 dB typical) so it would appear that the KPA-500 should be capable of clean operation with 5 W of drive (e.g., K3 in low power mode). 73, ... Joe, W4TV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Doug Faunt N6TQS +1-510-655-8604 Sent: Saturday, April 17, 2010 6:45 PM To: elecraft@mailman.qth.net Subject: [Elecraft] KPA500 active devices!! There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
Hi Joe Have you seen any IMD data on these devices? John --- On Sat, 4/17/10, Joe Subich, W4TV li...@subich.com wrote: From: Joe Subich, W4TV li...@subich.com Subject: Re: [Elecraft] KPA500 active devices!! To: 'Doug Faunt N6TQS +1-510-655-8604' fa...@panix.com, elecraft@mailman.qth.net Date: Saturday, April 17, 2010, 4:45 PM The VRF2933 is rated for 300 Watts each according to the data sheet on the manufacturer's web site (Microsemi) ... That makes their use in a 500 W amplifier reasonable from an IMD perspective. The VRF 2933 minimum gain is also 20dB (23 dB typical) so it would appear that the KPA-500 should be capable of clean operation with 5 W of drive (e.g., K3 in low power mode). 73, ... Joe, W4TV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Doug Faunt N6TQS +1-510-655-8604 Sent: Saturday, April 17, 2010 6:45 PM To: elecraft@mailman.qth.net Subject: [Elecraft] KPA500 active devices!! There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
Hi Brian Digikey has them listed for about 154 dollars per piece. The datasheet mentions superb IMD performance however there is no IMD data on the datasheet. I wonder if they perform as well as the MRF150's? in terms of IMD performance. John --- On Sat, 4/17/10, Brian Alsop als...@nc.rr.com wrote: From: Brian Alsop als...@nc.rr.com Subject: Re: [Elecraft] KPA500 active devices!! To: Cc: elecraft@mailman.qth.net Date: Saturday, April 17, 2010, 4:42 PM Just for curiosity, what do a pair of VRF2933 cost? Availability? 73 de Brian/K3KO Guy Olinger K2AV wrote: At any phase angle with no signal degradation. Minimum 20 dB gain, 300 watt output 400 typical per device. So being operated very conservatively. On Sat, Apr 17, 2010 at 7:22 PM, S Sacco nn4x.st...@gmail.com wrote: The VRF2933 is rated 3:1 Load VSWR Capability at Specifi ed Operating Conditions according to its datasheet; perhaps that's why there no built-in ATU. On Sat, Apr 17, 2010 at 6:44 PM, Doug Faunt N6TQS +1-510-655-8604 fa...@panix.com wrote: There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
Digi-Key has them listed at $153.34 each (Qty 1), down to $86.67 in lots of 1000. They have 30 in stock, if you want to order spares early :) 73 Dave KQ3T Brian Alsop wrote: Just for curiosity, what do a pair of VRF2933 cost? Availability? 73 de Brian/K3KO __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
digikey has them at $153.34 each now the PA is out of the bag, perhaps we will see progress on the long promised board to lock the radio to an external referencethe ext ref socket on the k3 has been blanked off for a long time now! Dave ww2r Message: 49 Date: Sat, 17 Apr 2010 23:42:39 + From: Brian Alsop als...@nc.rr.com Subject: Re: [Elecraft] KPA500 active devices!! Cc: elecraft@mailman.qth.net Message-ID: 4bca476f.8020...@nc.rr.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed Just for curiosity, what do a pair of VRF2933 cost? Availability? 73 de Brian/K3KO __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] KPA500 active devices!!
John, It's not shown on the datasheet. However, the VRF2933 is specified as a communications product (not a repurposed switching device) and is from the same family as the VRF150 (upgraded MRF150) which is specified at -32dBc (-38 dB to ARRL standard). Since the VFR2933 is a higher gain part (20 dB minimum gain) than the MRF150/VRF150, I would guess the IMD performance might be a bit worse at maximum output. Still, with the VRF2933 rated for 300W minimum - 375 typical at 50V - the KPA-500 is not pushing them at 500W. I'd look for IMD numbers on the mid to high 30's (ARRL spec). 73, ... Joe, W4TV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of juergen Sent: Saturday, April 17, 2010 7:50 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA500 active devices!! Hi Joe Have you seen any IMD data on these devices? John --- On Sat, 4/17/10, Joe Subich, W4TV li...@subich.com wrote: From: Joe Subich, W4TV li...@subich.com Subject: Re: [Elecraft] KPA500 active devices!! To: 'Doug Faunt N6TQS +1-510-655-8604' fa...@panix.com, elecraft@mailman.qth.net Date: Saturday, April 17, 2010, 4:45 PM The VRF2933 is rated for 300 Watts each according to the data sheet on the manufacturer's web site (Microsemi) ... That makes their use in a 500 W amplifier reasonable from an IMD perspective. The VRF 2933 minimum gain is also 20dB (23 dB typical) so it would appear that the KPA-500 should be capable of clean operation with 5 W of drive (e.g., K3 in low power mode). 73, ... Joe, W4TV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Doug Faunt N6TQS +1-510-655-8604 Sent: Saturday, April 17, 2010 6:45 PM To: elecraft@mailman.qth.net Subject: [Elecraft] KPA500 active devices!! There are two VRF2933's in push-pull, so they're not 750 watts each, but per pair. There are only three amps in existance, and no devices have been destroyed (yet). Again, 500 watts is a very conservative rating. It's been key-down for 10 minutes withy no problems. 73, doug __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
