[Elecraft] K3 Front End Protection
I have saw this posted before but not quite in this respect. I'm using 2 K3's with a Array Solutions SIXpack antenna controller SO2R, using 3 different antennas for HF a beam covering all bands 10-40m, vertical 10-160m and a OCFD @ 55' 270' long 10-160m. The OCFD is using the same tower as the beam only 10' from the feed point. The vertical a Hy Gain AV-18HT with a top mounted kit for 160m is only about 125' from the tower very good radial field. My B station K3 is a full Elecraft KPA500/KAT500/W2, the second A station is a K3/P3-SVGA into an Alpha 87A legal limit + Palstar HF-Auto. With these power levels I don't want to tempt fate but may very well like to use both radios at the same time while monitoring another band on the other radio and a quick call once in a while. I have looked at several front end protectors but they to be all for just receiving antennas and preamps no transmit ones Am I correct not to trust the built in protection in the K3 for this? It's a great radio but don't want to destroy it either by running that much power in antennas so close. If the K3 cannot handle this power could anyone guide me to a source that sells something that meets my needs. Thanks to all for your response. 73, Fred/N0AZZ __ 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] K3 Front End Protection
Fred, The best source of good information that I have found on operating multiple radios safely is the book by George Cutsogeorge, W2VJN: Managing Interstation Interferrence. It covers all the issues with running SO2R as well as other multi-transmitter configurations, and provides techniques to measure interference and mediate it. The book is available from Array Solutions here: http://www.arraysolutions.com/Products/Books/W2VJN_Interference.htm Antenna isolation is the name of the game and, particularly with QRO, requires a great deal of care and planning. I run 100W in an SO2R configuration with 2 K3's on a small city lot. My solution to the isolation problem has been the use of W3NQN bandpass filters and antenna geometries to minimize interaction. Using W2VJN's analysis techniques and employing some of the possible solutions noted by him, I can operate safely and have confidence that I am not damaging my K3's receiver. - 73, Stan - KR7C -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-Front-End-Protection-tp7567094p7567100.html Sent from the Elecraft 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] K3 Front End Protection
Stan Gibbs wrote and mediate it. Doh! That should be mitigate it. - 73, Stan - KR7C -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-Front-End-Protection-tp7567094p7567129.html Sent from the Elecraft 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] K3 Front End Protection
Stan Thanks I ordered the book looks like what I needed. Thx 73, Fred/N0AZZ -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Stan Gibbs Sent: Thursday, December 13, 2012 10:30 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Front End Protection Fred, The best source of good information that I have found on operating multiple radios safely is the book by George Cutsogeorge, W2VJN: Managing Interstation Interferrence. It covers all the issues with running SO2R as well as other multi-transmitter configurations, and provides techniques to measure interference and mediate it. The book is available from Array Solutions here: http://www.arraysolutions.com/Products/Books/W2VJN_Interference.htm Antenna isolation is the name of the game and, particularly with QRO, requires a great deal of care and planning. I run 100W in an SO2R configuration with 2 K3's on a small city lot. My solution to the isolation problem has been the use of W3NQN bandpass filters and antenna geometries to minimize interaction. Using W2VJN's analysis techniques and employing some of the possible solutions noted by him, I can operate safely and have confidence that I am not damaging my K3's receiver. - 73, Stan - KR7C -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-Front-End-Protection-tp7567094p75671 00.html Sent from the Elecraft 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 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2221 / Virus Database: 2634/5456 - Release Date: 12/13/12 __ 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] K3 front end protection
Hello, The K3 have enough protection itself to prevents large amounts of RF getting into the AUX input? I am looking for a switch for RX antennas, to connect to both RX ANT IN and AUX RF in the K3. I did a search in www and there´s two very interesting device. One is the DX Pedition II by KD9SV. A great tool, maybe more useful for radios without RX capabilities. It have a FRONT END SAVER and also very interesting that it relay the amp, this to protect the radio relays in some cases where it´s very small. So here is a great protection for the radio. The other device is the RAS 8x2 by K9AY. It is great to switch up to 8 RX antennas in both the main and subreceiver. But I don´t know more about the RAS 8x2, for example if the RAS 8x2 disconnect your receive antennas during transmit which prevents large amounts of RF (like the front end saver of the DXP II box) getting into the AUX and RX ANT inputs. Or this is not necessary in the RAS 8x2 because the disconnection of the RX antennas is made itself by the K3? Thanks for your feedback! 73, Jorge CX6VM/CW5W __ 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] K3 front-end protection
Hi Toby, [NOTE: I'm so busy that I'm answering about one e-mail a day, now, and yours is it :) Normally someone else will answer, or the answers will end up in the FAQ later on.] 1) A friend of mine with a big 160m station killed his RX front end because too much power was coming back on his beverages and the rig's RX antenna input was not grounded / disconnected during transmission by the transceiver. Are the K3 antenna inputs which might be used for RX only antennas protected against too much power coming back via the RX antenna? All antenna ports have gas-discharge tubes, and the RX-only ports also have carrier-operated relays. We also monitor the SWR bridge in receive mode (forward/reflected power). If a signal large enough to cause front-end damage appears in the main T-R path (a reverse transmit condition), we quickly open the PIN diode path to the receiver, typically in less than 1 ms. The path will recover equally fast when the huge external signal disappears. Obviously this situation is to be avoided, which is why such stations often use external band-pass filters. 2) At our contest QTH when we work multi between some of the antennas we also have a lot of power coming back - roughly 20W in the worst case combination of beams and bands (without the extra band passes). How strong is the RX front end of the K3? How much power can it handle without releasing its smoke? See above. At a certain power level the RX path will be opened (and the audio muted) to avoid exposing the preamp, mixer, and down-stream stages to multi-watt signals. 73, Wayne N6KR --- http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
