Re: [Elecraft] Isolation between Ant 1 and 2??
John King wrote: Has anyone else seen this crosstalk? Yep. I'm sure everyone that's tried it has. If so, what is considered acceptable? Well, that's harder to answer and entirely dependent upon your definition of acceptable. Clearly, the K3 wasn't designed to provide high isolation between the antenna ports - just look at the unshielded ANT1 and ANT2 leads in close proximity to each other. If they had been concerned about isolation, these runs would have been miniature coax (which you could easily install yourself.) In the scheme of things, though, the isolation isn't really too bad. Let's take your case: S3 to S9+20. That's 56 dB of isolation, which is about what one would expect from a typical commercial amateur radio grade antenna switch (pay no attention to the manufacturer's claims - I have measured them.) Isolation values of 80 dB and up are common in expensive commercial and military switches (Transco, Narda, etc.) So, it depends. I knew the port-to-port isolation in my K3 was going to be less than it could be when I built it. I though about installing RG-174 in place of the bare wires, but decided not to. I didn't see where it would buy me anything. All in all, I love my K3. I'm an engineer, and I've been on the air for over 40 years. The K3 is a real gem. 73, john WA1ABI -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net]on Behalf Of Dick Roth, KA1OZ Sent: Saturday, January 03, 2009 12:14 AM To: Elecraft Reflector Subject: [Elecraft] Isolation between Ant 1 and 2?? Hello and Happy New Year!! Was doing some testing and discovered Ant 1 signal on Ant 2. Ant 1 is my GAP Titan-DX and Ant 2 is a 100W dummy load. I was just reading the mail on 75 meters and switched to Ant 2 to test power. When key was off, I heard part of the QSO that was going on. While on my dummy load, I was receiving a station S3, which on Ant 1 was 20 over S9. Has anyone else seen this crosstalk? If so, what is considered acceptable? -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX ___ 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 Thanks for your input, John. It had been quite a few years before getting my K3 that I really had my hands in electronic gear. Once I left the world of two-way radio component-level troubleshooting and repair work and migrated into microwave radio system-level maintenance parts of my brain must have atrophied. 56 db really does seem adequate after all. It all really does have to do with perspective. By the way...I love my K3! Regardless of the era of ownership (last HF rig=National NCX-3), it is the finest piece of electronics I've ever owned. -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX ___ 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
AW: [Elecraft] Isolation between Ant 1 and 2??
yes isolation between ant1 and ant2 is very bad... if I have time I try to change the silgle wires from the rs323 ports to the atu-board to koax wires, maybe this will help a little 73 OE6KYG KX1 244 K2 1331 K3 115 -Ursprüngliche Nachricht- Von: elecraft-boun...@mailman.qth.net [mailto:elecraft- boun...@mailman.qth.net] Im Auftrag von Dick Roth, KA1OZ Gesendet: Samstag, 03. Jänner 2009 06:14 An: Elecraft Reflector Betreff: [Elecraft] Isolation between Ant 1 and 2?? Hello and Happy New Year!! Was doing some testing and discovered Ant 1 signal on Ant 2. Ant 1 is my GAP Titan-DX and Ant 2 is a 100W dummy load. I was just reading the mail on 75 meters and switched to Ant 2 to test power. When key was off, I heard part of the QSO that was going on. While on my dummy load, I was receiving a station S3, which on Ant 1 was 20 over S9. Has anyone else seen this crosstalk? If so, what is considered acceptable? -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX ___ 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 ___ 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
[Elecraft] Isolation between Ant 1 and 2??
Do not assume that this entirely due to poor isolation. Much of it probably is, but not all. I remember about 40+ years ago, hearing a friend on 15m on a dead band. He was only around 2 miles from, but he was really weak. I called him. Turns out, he was testing on his DUMMY LOAD. No second antenna port (his was a Galaxy V Mk II). Obviously, the dummy load was not total isolation. Or if it was, then the coax going to it was not. He was using a Heath Cantenna. How many others have had a QSO using their dummy load or were able to hear other stations while using their dummy load? How many have tried? An easy test would be to keep the DL connected and disconnect the other coax from the rig. Then calculate the difference. My K3s only have Ant 1, so not possible to try here. de Doug KR2Q ___ 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
Re: AW: [Elecraft] Isolation between Ant 1 and 2??
I would consider that figure acceptable. With my K3 the isolation between ANT1 and ANT2 is 42dB worst case, 56dB Max. Moving the single wires around made no difference. I suspect that the level of isolation is determined by the ATU PCB layout. Given the size of that board I think that the isolation obtained is reasonable. 73 Stewart G3RXQ On Sat, 3 Jan 2009 13:43:21 +0100, Koppendorfer Klaus wrote: yes isolation between ant1 and ant2 is very bad... if I have time I try to change the silgle wires from the rs323 ports to the atu-board to koax wires, maybe this will help a little 73 OE6KYG KX1 244 K2 1331 K3 115 -Ursprüngliche Nachricht- Von: elecraft-boun...@mailman.qth.net [mailto:elecraft- boun...@mailman.qth.net] Im Auftrag von Dick Roth, KA1OZ Gesendet: Samstag, 03. Jänner 2009 06:14 An: Elecraft Reflector Betreff: [Elecraft] Isolation between Ant 1 and 2?? Hello and Happy New Year!! Was doing some testing and discovered Ant 1 signal on Ant 2. Ant 1 is my GAP Titan-DX and Ant 2 is a 100W dummy load. I was just reading the mail on 75 meters and switched to Ant 2 to test power. When key was off, I heard part of the QSO that was going on. While on my dummy load, I was receiving a station S3, which on Ant 1 was 20 over S9. Has anyone else seen this crosstalk? If so, what is considered acceptable? -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX ___ 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 ___ 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 ___ 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
[Elecraft] Isolation between Ant 1 and 2??
Hello and Happy New Year!! Was doing some testing and discovered Ant 1 signal on Ant 2. Ant 1 is my GAP Titan-DX and Ant 2 is a 100W dummy load. I was just reading the mail on 75 meters and switched to Ant 2 to test power. When key was off, I heard part of the QSO that was going on. While on my dummy load, I was receiving a station S3, which on Ant 1 was 20 over S9. Has anyone else seen this crosstalk? If so, what is considered acceptable? -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX ___ 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
