To those interested, I have several brand new 1000' wooden reels of Commscope RG-6 coax for $75/ reel. Willy K3VW In a message dated 1/16/2011 1:32:40 P.M. Eastern Standard Time, [email protected] writes:
Send Topband mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit http://lists.contesting.com/mailman/listinfo/topband or, via email, send a message with subject or body 'help' to [email protected] You can reach the person managing the list at [email protected] When replying, please edit your Subject line so it is more specific than "Re: Contents of Topband digest..." Today's Topics: 1. Shunt tower help (James C. Hall, MD) 2. First attempt at beverage antenna, not working as expected (Mark Lunday) 3. Re: Shunt tower help (James C. Hall, MD) 4. Re: First attempt at beverage antenna, not working as expected (Mark Lunday) 5. Re: First attempt at beverage antenna, not working as expected (Greg - ZL3IX) 6. Re: First attempt at beverage antenna, not working as expected (KL7RA) 7. TB Recovery? ([email protected]) 8. Re: First attempt at beverage antenna, not working as expected (Rick Stealey) 9. Re: First attempt at beverage antenna, not working as expected (Rik van Riel) 10. Re: First attempt at beverage antenna, not working as expected ([email protected]) ---------------------------------------------------------------------- Message: 1 Date: Sat, 15 Jan 2011 16:22:43 -0600 From: "James C. Hall, MD" <[email protected]> Subject: Topband: Shunt tower help To: <[email protected]> Message-ID: <005401cbb502$bb3006c0$31901440$@com> Content-Type: text/plain; charset="us-ascii" Hello TB: I have a problem -I cannot seem to get a decent match either with Gamma or Omega matching. My situation is a complex one that doesn't lend well to modeling and I am forced to trying trial and error - mostly the latter. My tower is 120 feet of Rohn 45 that has attached (non-insulated) EHS guy wires which makes it essentially a pyramidal cage vertical. I have two yagis in a stack arrangement that each have a 44 foot boom with insulated elements - one at 120', and the other at 60' on a TIC ring rotator. The shunt (gamma) wire must be attached below this lower antenna an is at about 56 feet. It is separated from the tower by 22". Right now I don't have much in the way of a radial system - I'll just leave it at that for now. I have two vacuum variable capacitors available to me - a 350pf and a 1000pf. With just a gamma arrangement, I can get the SWR to about 5:1. At this point, my MFJ antenna analyzer shows a Rs=5 and Xs=0. Now, upon hooking up the omega capacitor (parallel to ground), and with all the threads at minimum (minimum capacitance), the Rs jumps up to 194 with Xs remaining at 0. Adding capacitance here will increase the Rs further. I just don't know what to do at this point. I would appreciate any guidance to this situation - while I still have hair I haven't pulled out ! 73, Jamie WB4YDL ======= Email scanned by PC Tools - No viruses or spyware found. (Email Guard: 7.0.0.21, Virus/Spyware Database: 6.16700) http://www.pctools.com/ ======= ------------------------------ Message: 2 Date: Sat, 15 Jan 2011 21:14:09 -0500 From: "Mark Lunday" <[email protected]> Subject: Topband: First attempt at beverage antenna, not working as expected To: <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset="us-ascii" My first beverage, I was expecting better results. I could only roll out 250 feet of new, insulated 14 gauge stranded wire, but I did get it consistently about 6 feet above ground. The ground slopes away at about 10 degrees angle and at the end of the wire the slope increases to 35 degrees and goes into a creek bed. The ground then rises again on the other side of the creek bed. 250 kV power lines on 200 foot towers at 600 foot away, although no noise is noticed. I do have the 450 ohm resistor at the far end for termination, a ground rod at each end with somewhat moist conditions (snow melt), 250 foot of low loss coax. The transformer and resistor are from DX engineering, so I do not suspect an issue with the parts. I read that a bev antenna "wants to work" What I hear on 40, 80, and 160 is a much lower noise floor, no gain (none expected), but I don't hear a better S/N on the EU stations - beverage pointed 045 true from here in NC. I expected to hear the EU stations "better" on the beverage. I am using a Flex 3000, so I do not have (nor should I need) a pre-amp. Any suggestions welcome. I realize that the length is not optimum for 160, but it should do better than my inverted L. Thanks Mark Lunday WD4ELG ------------------------------ Message: 3 Date: Sat, 15 Jan 2011 20:15:11 -0600 From: "James C. Hall, MD" <[email protected]> Subject: Re: Topband: Shunt tower help To: <[email protected]> Message-ID: <00ad01cbb523$3e58f050$bb0ad0f0$@com> Content-Type: text/plain; charset="us-ascii" Hello TB: Thanks so much for the great replies !! Bottom line is I need to insulate the tower from the guys. Several mentioned using a grid dipper to discover the actual resonant frequency of the tower and then go from there. This spring, I'll definitely do both and then get back in the action. Thanks again. 73, Jamie WB4YDL ======= Email scanned by PC Tools - No viruses or spyware found. (Email Guard: 7.0.0.21, Virus/Spyware Database: 6.16700) http://www.pctools.com/ ======= ------------------------------ Message: 4 Date: Sat, 15 Jan 2011 21:44:53 -0500 From: "Mark Lunday" <[email protected]> Subject: Re: Topband: First attempt at beverage antenna, not working as expected To: "'Mark Lunday'" <[email protected]>, <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset="us-ascii" Additional notes: EU stations that I can hear S7 on the 80 meter half-square, are reduced to NIL on the beverage. I can hear some US stations to the NE. _____________________________________________ From: Mark Lunday [mailto:[email protected]] Sent: Saturday, January 15, 2011 9:14 PM To: '[email protected]' Subject: First attempt at beverage antenna, not working as expected My first beverage, I was expecting better results. I could only roll out 250 feet of new, insulated 14 gauge stranded wire, but I did get it consistently about 6 feet above ground. The ground slopes away at about 10 degrees angle and at the end of the wire the slope increases to 35 degrees and goes into a creek bed. The ground then rises again on the other side of the creek bed. 250 kV power lines on 200 foot towers at 600 foot away, although no noise is noticed. I do have the 450 ohm resistor at the far end for termination, a ground rod at each end with somewhat moist conditions (snow melt), 250 foot of low loss coax. The transformer and resistor are from DX engineering, so I do not suspect an issue with the parts. I read that a bev antenna "wants to work" What I hear on 40, 80, and 160 is a much lower noise floor, no gain (none expected), but I don't hear a better S/N on the EU stations - beverage pointed 045 true from here in NC. I expected to hear the EU stations "better" on the beverage. I am using a Flex 3000, so I do not have (nor should I need) a pre-amp. Any suggestions welcome. I realize that the length is not optimum for 160, but it should do better than my inverted L. Thanks Mark Lunday WD4ELG ------------------------------ Message: 5 Date: Sun, 16 Jan 2011 20:36:16 +1300 From: Greg - ZL3IX <[email protected]> Subject: Re: Topband: First attempt at beverage antenna, not working as expected To: [email protected] Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hi Mark, 250ft is VERY short for a TB Beverage. You will get some F/B, but the front lobe will be very broad. Can you extend it at all, maybe asking some kind neighbours to use a bit of their land? 500 ft is really about minimum and 1000 ft even better. 73, Greg, ZL3IX On 2011-01-16 15:14, Mark Lunday wrote: > My first beverage, I was expecting better results. > > I could only roll out 250 feet of new, insulated 14 gauge stranded wire, but > I did get it consistently about 6 feet above ground. ------------------------------ Message: 6 Date: Sun, 16 Jan 2011 00:05:33 -0900 From: "KL7RA" <[email protected]> Subject: Re: Topband: First attempt at beverage antenna, not working as expected To: "Mark Lunday" <[email protected]>, <[email protected]> Message-ID: <004e01cbb55c$8b93a980$6e49a8c0@40M> Content-Type: text/plain; charset="iso-8859-1" > My first beverage, I was expecting better results. Most will mention 250 feet is too short and that might be the reason as it will not match 9:1 or that 450 Ohm resistor. A working beverage is easy to recognize as the noise drops to zero and signals really "pop" out of the noise. They are magic antennas when they are built correctly and I can tell quickly when one has a problem. I suggest measuring the antenna with a MFJ 259B and check the SWR. All mine run around 2:1 from 1.8 to maybe 2.2 Mhz. If the SWR is high and the coax and all connections are okay I would change the length some how to 500+ feet or use one of the variable transformers with its variable resistor package sold by some companies that sell Beverage electronics. By the way I built a new Beverage this winter and it didn't work, excess SWR. I found the new 500 ft spool of RG-6 from Home depot had a bad spot in it where there spliced the cable by a simple overlap of the braid. 73 Rich KL7RA ------------------------------ Message: 7 Date: Sun, 16 Jan 2011 09:54:29 +0100 (CET) From: [email protected] Subject: Topband: TB Recovery? To: [email protected] Message-ID: <[email protected]> Content-Type: text/plain;charset=iso-8859-1 Looks like condx are back to what they were say 5 years back with deep downs and huge ups. Great openings to midwest the past week (599 sigs from W0BV, W0FLS, AA0RS etc. Also good propagations to VK, DU and YB during the same time. But where are the JA:s?? Also heard W6OAR 579 a few days ago. 73 SM6CPY Carl ----------------------------------------- Skaffa gratis e-post du ocks? p? http://www.sverige.nu ------------------------------ Message: 8 Date: Sun, 16 Jan 2011 14:15:00 +0000 From: Rick Stealey <[email protected]> Subject: Re: Topband: First attempt at beverage antenna, not working as expected To: <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset="iso-8859-1" Sounds like "maybe" something is not working. If you have an antenna analyzer can you do a sweep from 160 up to 40 m? There should be a relatively flat SWR over the whole range. Without the far end terminated the impedance and therefore the SWR will flop all over the place. That would show you that the transformer, resistor and connections are ok. Then measure down at the shack end of the coax and it should also be flat, maybe even a little flatter. If you suspect the coax you can also get a loss reading on it with the antenna analyzer by open circuiting it and taking a reading. Your length is a bit short, though. As I understand the Bev starts playing pretty well at 500 feet and up, so your results might be what's expected. Mine is 550 feet and most of the time it beats the inv L on EU signals from here in NJ. But not always, and sometimes the difference is minimal. But there are times when a signal is at the noise level on the L, and switching to the Beverage it becomes readable but not a HUGE difference. Rick K2XT ------------------------------ Message: 9 Date: Sun, 16 Jan 2011 09:39:44 -0500 From: Rik van Riel <[email protected]> Subject: Re: Topband: First attempt at beverage antenna, not working as expected To: [email protected] Message-ID: <[email protected]> Content-Type: text/plain; charset=UTF-8; format=flowed On 01/15/2011 09:44 PM, Mark Lunday wrote: > Additional notes: > > EU stations that I can hear S7 on the 80 meter half-square, are reduced to > NIL on the beverage. > > I can hear some US stations to the NE. That seems consistent with a half wave beverage having a really really high takeoff angle. Something on the order of 70 degrees, IIRC... *googles around* Ahhh, there is the web page with that info: http://www.seed-solutions.com/gregordy/Amateur%20Ra dio/Experimentation/Beverage.htm -- All rights reversed. ------------------------------ Message: 10 Date: Sun, 16 Jan 2011 10:43:54 -0500 (EST) From: <[email protected]> Subject: Re: Topband: First attempt at beverage antenna, not working as expected To: [email protected] Message-ID: <[email protected]> Content-Type: text/plain; charset=us-ascii Hi Rick, Obviously something is very wrong with your new Beverage. While your Beverage is too short for really good performance on 160 meters, it should perform very well on 80 and 40 meters. Please run some tests on those bands. If its not performing as you expect on 80 and 40, you have some kind of serious problem in the antenna, transmission line or connectors. A simplest measurement you can make is DC resistance. Assuming your matching transformer provides a DC short across the far end of your coaxial cable, the shack end of the coax cable should read just one or two ohms. If thats okay, you need to make some RF measurements. An MFJ-259 is an excellent and inexpensive tool. With the Beverage terminated you should see VSWR less than 1.5:1 across a broad frequency range. When you remove the termination, the VSWR should change dramatically with frequency. Please share your results with us. Beverages just want to work, its nearly impossible to get really poor performance without a fault in the system unless its installed over salt water. Good luck! 73 Frank W3LPL ---- Original message ---- >Date: Sun, 16 Jan 2011 14:15:00 +0000 >From: Rick Stealey <[email protected]> >Subject: Re: Topband: First attempt at beverage antenna, not working as expected >To: <[email protected]> > > >Sounds like "maybe" something is not working. If you have an antenna analyzer >can you do a sweep from 160 up to 40 m? There should be a relatively flat >SWR over the whole range. Without the far end terminated the impedance and >therefore the SWR will flop all over the place. That would show you that the >transformer, resistor and connections are ok. Then measure down at the >shack end of the coax and it should also be flat, maybe even a little >flatter. If you suspect the coax you can also get a loss reading on >it with the antenna analyzer by open circuiting it and taking a reading. >Your length is a bit short, though. As I understand the Bev starts >playing pretty well at 500 feet and up, so your results might be what's >expected. Mine is 550 feet and most of the time it beats the inv L >on EU signals from here in NJ. But not always, and sometimes the >difference is minimal. But there are times when a signal is at the >noise level on the L, and switching to the Beverage it becomes readable >but not a HUGE difference. >Rick K2XT > >_______________________________________________ >UR RST IS ... ... ..9 QSB QSB - hw? BK ------------------------------ _______________________________________________ Topband mailing list [email protected] http://lists.contesting.com/mailman/listinfo/topband End of Topband Digest, Vol 97, Issue 18 *************************************** _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
