Isolation between Ant 1 and 2??
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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: [hidden email] 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 |
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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: [hidden email] >> [mailto:[hidden email]]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: [hidden email] >> 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: [hidden email] 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: Isolation between Ant 1 and 2??
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In reply to this post by raroth7
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: [hidden email] [mailto:elecraft- > [hidden email]] 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: [hidden email] > 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: [hidden email] 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: Isolation between Ant 1 and 2??
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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: [hidden email] [mailto:elecraft- >> [hidden email]] 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. >> 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: [hidden email] >> 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: [hidden email] > 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: [hidden email] 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 |
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