Topband: Phase lines
Hi Ed Can you share some of that information. I didn't think 259b couldn't do 75 ohm coax. CU Lloyd K5ZO _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 160 Meter Radio Propagation Prediction Table
Moscow, Raoul, I believe.72 Jim R. K9JWV Africa is not part of their world? I thought so, as my radio also seems to say I live in a Black 160m hole.:-) bTW Where is Mos? kind regards,Raoul ZS1C _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 160 Meter Radio Propagation Prediction Table
http://www.w0btu.com/AM-longwaveStations.html is likely out of date, On Jul 12, 2016 9:09 AM, "K1FZ-Bruce" wrote: > > > Years ago, some of the 80 meter Dxers used to monitor a commercial JA > broadcast frequency. It was a good indicator of Japanese propagation. > Anyone done this on 160 meters?.if yes, what frequency, call sign ? > > Bruce-K1FZ > http://www.qsl.net/k1fz/beverage_antenna.html > > > > .I know, I KNOW . top band propagation predictors are about > useless BUT, Hey..anything is worth a looksee.doncha know?!?! > > You see this in the write up below the "dashboard" (url at the bottom of > this post) "A GREEN box means that propagation on the specific path > might be possible..." > > 71.5/72 de Jim Rodenkirch K9JWV > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 160 Meter Radio Propagation Prediction Table
Africa is not part of their world? I thought so, as my radio also seems to say I live in a Black 160m hole.:-) bTW Where is Mos? kind regards,Raoul ZS1C From: James Rodenkirch To: Top Band Contesting Sent: Tuesday, July 12, 2016 3:22 PM Subject: Topband: 160 Meter Radio Propagation Prediction Table ..I know, I KNOW . top band propagation predictors are about useless BUT, Hey..anything is worth a looksee.doncha know?!?! You see this in the write up below the "dashboard" (url at the bottom of this post) "A GREEN box means that propagation on the specific path might be possible..." We all know anything is possible..it's when some numerical probability is assigned we know some true "measuring" was performed AND we know measuring and predicting propagation on top band can approach whimsical BUTconsider this a "tool," of sortsI see where the page is updated every five minutes. 71.5/72 de Jim Rodenkirch K9JWV P.S. Enjoy the days ahead!! http://www.spacew.com/www/160pred.html _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Cutting Delay Lines
Thanks Wes and thanks all who replied directly . I've received some very good information. I should be good to go Ed N5DG On 7/13/2016 9:45 AM, Wes Stewart wrote: I have no idea how critical the phase shift is for your design, but I'll offer a couple of caveats. Unless you have characterized your cable, you don't know Vf or Zo. Furthermore, both of these vary with frequency. These effects are probably in the noise and with your instrumentation you will never know the difference. That said, finding a phase length at a multiple frequency doesn't necessarily predict the phase length at the design frequency. On 7/12/2016 8:04 PM, Ed Stallman wrote: I'm cutting a 40 degree and a 20 Degree Delay line using RG6 at 1.83MHz for a receive 8 circle array ! I know the velocity factor of the RG6 and have all the math worked out . After doing the calculations and trimming the RG6 back , I'm looking for X=0 at 4.118 MHZ ( or as close to X=0 as possible ) Now to my question: I'm finding the X=0 to be a broad range , looks to be + - 50 KHz on my MFJ 259b .. I know , I need a better analyzer ... Can I double of quadruple the frequency to narrow the span where X=0? Thanks Ed N5DG --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Cutting Delay Lines
I have no idea how critical the phase shift is for your design, but I'll offer a couple of caveats. Unless you have characterized your cable, you don't know Vf or Zo. Furthermore, both of these vary with frequency. These effects are probably in the noise and with your instrumentation you will never know the difference. That said, finding a phase length at a multiple frequency doesn't necessarily predict the phase length at the design frequency. On 7/12/2016 8:04 PM, Ed Stallman wrote: I'm cutting a 40 degree and a 20 Degree Delay line using RG6 at 1.83MHz for a receive 8 circle array ! I know the velocity factor of the RG6 and have all the math worked out . After doing the calculations and trimming the RG6 back , I'm looking for X=0 at 4.118 MHZ ( or as close to X=0 as possible ) Now to my question: I'm finding the X=0 to be a broad range , looks to be + - 50 KHz on my MFJ 259b .. I know , I need a better analyzer ... Can I double of quadruple the frequency to narrow the span where X=0? Thanks Ed N5DG --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Cutting Delay Lines
In principle, any *odd* multiple of 4.118 MHz (the frequency where the cable is 1/4 wavelengths long) will work when the far end of the cable is open-circuited. If you short-circuit the far end of the cable, then look for X=0 at *even* multiples of 4.118 MHz. 73, John W1FV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Ed Stallman Sent: Tuesday, July 12, 2016 11:05 PM To: Topband Subject: Topband: Cutting Delay Lines I'm cutting a 40 degree and a 20 Degree Delay line using RG6 at 1.83MHz for a receive 8 circle array ! I know the velocity factor of the RG6 and have all the math worked out . After doing the calculations and trimming the RG6 back , I'm looking for X=0 at 4.118 MHZ ( or as close to X=0 as possible ) Now to my question: I'm finding the X=0 to be a broad range , looks to be + - 50 KHz on my MFJ 259b .. I know , I need a better analyzer ... Can I double of quadruple the frequency to narrow the span where X=0? Thanks Ed N5DG --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
