Advice!
Locked
 
|
When running the KPA500 on AM, it there any time limit before unkeying?
While operating, the fan comes on and then it kicks into another speed. Thanks Phil Philip LaMarche LaMarche Enterprises, Inc <mailto:[hidden email]> [hidden email] <http://www.lamarcheenterprises.com/> www.LaMarcheEnterprises.com 727-944-3226 727-937-8834 Fax 727-510-5038 Cell <http://www.w9dvm.com/> www.w9dvm.com K3 # 1605 KPA500 # 029 CCA 98-00827 CRA 1701 W9DVM ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
Phil,
AM with its 50% power carrier and sidebands that change in amplitude should present a less harsh situation than RTTY which is 100% duty cycle. There have been reports of running RTTY for an extended time with no harm. But the specification says 500 watts with 10 minutes key down and 5 minutes standby. It should do at least that well with AM. The KPA500 has temperature alarms should it get too hot, so it should "take care of itself". 73, Don W3FPR On 7/30/2011 2:49 PM, Phil LaMarche wrote: > When running the KPA500 on AM, it there any time limit before unkeying? > While operating, the fan comes on and then it kicks into another speed. > > > > Thanks > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
That should actually about 25% carrier.
125-150 watts carrier - 500-600w PEP AM. Shouldn't be any problem for the KPA-500. Presuming one doesn't make an hour long old buzzard transmission. Sent from my iPhone On Jul 30, 2011, at 2:24 PM, Don Wilhelm <[hidden email]> wrote: > Phil, > > AM with its 50% power carrier and sidebands that change in amplitude > should present a less harsh situation than RTTY which is 100% duty > cycle. There have been reports of running RTTY for an extended time > with no harm. But the specification says 500 watts with 10 minutes key > down and 5 minutes standby. It should do at least that well with AM. > > The KPA500 has temperature alarms should it get too hot, so it should > "take care of itself". > > 73, > Don W3FPR > > On 7/30/2011 2:49 PM, Phil LaMarche wrote: >> When running the KPA500 on AM, it there any time limit before unkeying? >> While operating, the fan comes on and then it kicks into another speed. >> >> >> >> Thanks >> >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Don Wilhelm-4
Don, > AM with its 50% power carrier and sidebands that change in amplitude > should present a less harsh situation than RTTY which is 100% duty > cycle. AM carrier power is 25% of PEP (not 50%). The RF voltage and current are each 50% of peak values which makes power 25% of peak. The US "legal limit" for AM is 375W carrier (1500/4). For the KPA-500 this means 125W (certainly no more than 150W) carrier. 73, ... Joe, W4TV On 7/30/2011 3:24 PM, Don Wilhelm wrote: > Phil, > > AM with its 50% power carrier and sidebands that change in amplitude > should present a less harsh situation than RTTY which is 100% duty > cycle. There have been reports of running RTTY for an extended time > with no harm. But the specification says 500 watts with 10 minutes key > down and 5 minutes standby. It should do at least that well with AM. > > The KPA500 has temperature alarms should it get too hot, so it should > "take care of itself". > > 73, > Don W3FPR > > On 7/30/2011 2:49 PM, Phil LaMarche wrote: >> When running the KPA500 on AM, it there any time limit before unkeying? >> While operating, the fan comes on and then it kicks into another speed. >> >> >> >> Thanks >> >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Phil LaMarche-2
At low heat levels, the fans operate at low speeds.
As the temperature of the PA rises, the fans increase in speed (and they're louder). Depending on humidity, ambient temperature, and the free space around the amplifier, the increased fan speed moves heat energy out of the amplifier. If the PA transistors get "too warm", the firmware causes a temperature-related fault. That shuts the amplifier down until the temperature returns to a safe level. During development a number of amplifiers were subjected to very long key down times, sometimes with restricted airflow. We've exercised the protection logic quite a bit. That doesn't mean you need to run with all the knobs to the right, but if the fans are running, that's good, heat is being moved out. The PA devices are not being operated at their maximum thermal rating. The KPA500 temperature fault occurs before the RF transistor manufacturer's maximum temperature rating. Dick, K6KR -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Phil LaMarche Sent: Saturday, July 30, 2011 11:49 AM To: [hidden email] Subject: [Elecraft] Advice! When running the KPA500 on AM, it there any time limit before unkeying? While operating, the fan comes on and then it kicks into another speed. Thanks Phil Philip LaMarche LaMarche Enterprises, Inc <mailto:[hidden email]> [hidden email] <http://www.lamarcheenterprises.com/> www.LaMarcheEnterprises.com 727-944-3226 727-937-8834 Fax 727-510-5038 Cell <http://www.w9dvm.com/> www.w9dvm.com K3 # 1605 KPA500 # 029 CCA 98-00827 CRA 1701 W9DVM ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Don Wilhelm-4
Many thanks for all the responses regarding AM operation. I'm good to go
and am happy to use the K3 on AM, having gotten rid of my heavy metal. Everyone have a great weekend. Phil Philip LaMarche LaMarche Enterprises, Inc [hidden email] www.LaMarcheEnterprises.com 727-944-3226 727-937-8834 Fax 727-510-5038 Cell www.w9dvm.com K3 # 1605 KPA500 # 029 CCA 98-00827 CRA 1701 W9DVM -----Original Message----- From: Don Wilhelm [mailto:[hidden email]] Sent: Saturday, July 30, 2011 3:25 PM To: Phil LaMarche Cc: [hidden email] Subject: Re: [Elecraft] Advice! Phil, AM with its 50% power carrier and sidebands that change in amplitude should present a less harsh situation than RTTY which is 100% duty cycle. There have been reports of running RTTY for an extended time with no harm. But the specification says 500 watts with 10 minutes key down and 5 minutes standby. It should do at least that well with AM. The KPA500 has temperature alarms should it get too hot, so it should "take care of itself". 73, Don W3FPR On 7/30/2011 2:49 PM, Phil LaMarche wrote: > When running the KPA500 on AM, it there any time limit before unkeying? > While operating, the fan comes on and then it kicks into another speed. > > > > Thanks > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
|
|
In reply to this post by Joe Subich, W4TV-4
Joe,
You are correct - I was looking at the RF voltage - not the power. 73, Don W3FPR On 7/30/2011 3:47 PM, Joe Subich, W4TV wrote: > > Don, > > > AM with its 50% power carrier and sidebands that change in amplitude > > should present a less harsh situation than RTTY which is 100% duty > > cycle. > > AM carrier power is 25% of PEP (not 50%). The RF voltage and current > are each 50% of peak values which makes power 25% of peak. The US > "legal limit" for AM is 375W carrier (1500/4). For the KPA-500 this > means 125W (certainly no more than 150W) carrier. > > 73, > > ... Joe, W4TV > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
«
Return to [QRO]
|
1 view|%1 views
| Free forum by Nabble | Edit this page |