delara newsDelaware Amateur Radio Association, Delaware OH VOL 37 NUMBER 11
DELARA At the ARC
An Antenna Mystery - Solved! But you won’t believe the cause! Under the tireless efforts of Dale, W8KTQ, DELARA version 2.0 is rapidly taking shape! We left off last months with the new operating desks having been delivered and rolled into place. Tim’s handiwork will be a great foundation for our operating. Dale started this month off:- Completed making, testing, installing and labeling the four 14' jumpers on the north lightning arrestors and ran them into the room.- Went to connect them to the back of the feed-thru connectors on the MFJ Patch Panel but quickly discovered the lock-washers and nuts we put on were not holding tight. Decided to end the madness and JB weld them to the panel!! Started with the antenna feed-thrus (top row) first and the next day, found out that the bottom ones weren't any better so I tore the entire panel out and JB'd all of them. Also decided not to use the Right-Angle SO-239 connectors as there is barely enough room to tighten them down so I extended the panel out more so we can hook the coax feeds directly to the feed-thrus. In the mean time, I hooked the beam directly to ANT Pos 1 on the 950 and the GOTA dipole directly to ANT Pos 2. This is temporary until the panel gets put back together. This is WIP so I plan to finish it up tomorrow once the JB dries completely. The radio is operational at this point.- I measured how much coax we have to connect from the dipoles into the arrestors. Turns out there are 5-50' rolls and 1-38' roll of RG-213. I labeled and coiled them back up for now until we're ready to use them.- I added a shelf to the Station #1 table for the computer to sit on. Will do the other tables as I have time.- The W2AU 1:1 baluns finally came today so I'll start putting the dipoles together. - We are planning a work day Friday afternoon (weather depending) probably around 1pm but not certain at this point. The goal will be to lay out the coax through the grass and then use the RG8X coax up to the dipoles to see how much of it we need. Bob Dixon has offered to put connectors on the RG8X coax once we have it cut to length. We'll work on it this weekend or Monday.The JB Weld is dry and all connections are back as they should be, tight this time! The top row is for antennas and the bottom row goes to the radios with one EXCEPTION: the last one on the right on the bottom is the HF VERTICAL as I had 7 antennas and six connectors. I sacrificed the HF3-2 position which is on the right wall as you come into the room. Station 1 is now hooked back up through the panel.We put up the 80M CW and the 40M CW dipoles this afternoon. The 80 resonated around 3503 with an SWR of 1.3:1. The 40 gave us fits! Both antennas had brand new W2AU 1:1 baluns and the lowest SWR we could get on the 40 was 2.9:1 at 6.95 Mhz. I cut it long on purpose so we could trim it to get it to where we wanted so the 6.95 didn't surprise me but the fact we could not get the SWR down was frustrating. We actually suspected a bad balun so we took it out and just went direct with coax to see what it would be. Still around 2.9:1!!! OK, is the wire bad?????? Using Joe's #18 copper clad wire but used it on the 80CW and it worked fine.
I brought it home to troubleshoot so the jury is still out. Joe (MP) suggested that the balun might be mis-marked and actually be a 4:1...….hmmmmm, a possibility but have not had time to test it yet. But it wasn't any better with the balun out so will have to investigate further. We temporarily used RG-213 coax to test both dipoles but took them off when we left. We did leave the 80CW dipole up as the antenna needs to be stretched so the wire doesn't coil up. Will replace it with RG8X which we measured and cut for all three dipoles. I have to make the 40M PH dipole yet and will put it up in the next couple of days. We found out that we can run the 40CW and the 80CW dipole coaxes directly to the tower 15-20' up so we won't have to lay them on the ground. The 40PH (farthest north dipole) will have to be run to a stake at the woods edge and then in the grass to the arrestors. That's a 200' run but there's no other way to do it. When Field Day comes around, we can just disconnect it from the arrestor and run it to Stan's station. I also cut the remaining shelves for the computer tables but didn't have a chance to install them yet.Thanks to everyone who showed up to help! Joe (TA), Larry (HTT), Donn, Stan and Jamie. George was there too performing his magic!!George reports: I purchased a DLINK Router for the ARC. The Video Adapter came in also. And my ANTI Melt Down program is done so I will head to the ARC tomorrow to install and test this stuff. Hope to see you folks there. The anti melt down program sits between the FT2000RC program and the FT950 and monitors the data stream on the RS232 connection. It looks for a signal that puts the FT950 into transmit. If it detects an XT signal it will watch for an RX signal to return to receive mode. If it does not detect an RX signal within a designated time period it will shut down the transmitter and turn the rig off. Eventually I hope to also disconnect AC power to the rig. I hope the DLINK router will get us on the WEB as an independent station. And I hope the Video Adapter will let us work with two monitors on each station. (It did.) The radio setup is progressing. The Yaesu 950 is in and operational (withi remote operating to come soon). The Kenwood 120 digital station is set, awaiting PC placement. The ARES desk with 2 Yaesu 8800’s and a DMR radio is set, awaiting PC placement and antenna feeds.
…and the solution? What was causing the problem??Thanks to Bob Dixon for providing the PL-259 and reducer connectors Saturday. He and I put six of them on three long lengths of RG8X coax for the dipoles. I looked into why the 40M CW dipole I made had a consistent SWR of 2.9:1. I tested the new balun and it was fine so the only thing left was the wire. I examined it closely and found small rust spots on it every couple of inches. I really didn't think this would be the problem but then I got to thinking about skin effect and the fact that RF current flows on the surface of a conductor. With no other choice, I found shiny copper coated wire on the roll that Joe (MP) gave me, cut it to length, put it together and believe it or not, the SWR was 1:1 with the dipole 2' off the ground! Wala! Problem resolved! Who woulda thunk it??? (See pic;). Guess that's a good reminder not to use rusty wire for an antenna or coax that has black on the outside of the center conductor or outside of the braid. It just won't work!!! Most times too, when you find a piece of coax that has been compromised like that, it will ruin the entire length of coax no matter how long it is. Good reason to use coax seal or other weatherproofing material that will stop moisture from getting into it.Today, I put up both the 80CW and the 40CW dipoles between the south and north trees (end to end) with about 20' of separation. I ran both lengths of coax in to the north lightning arrestors, hooked everything up and went inside to test. The 80CW antenna worked fine but the 40CW had a very high SWR! Troubleshooting revealed that it looks like a couple of the lightningn arrestors are bad so I temporarily bypassed them until I can troubleshoot more. I ran out of time to make the 40PH dipole but will do that this week and add it to the lineup. I re-connected the beam to the 950 ANT 1 position and put the 40CW dipole on ANT 2, replacing the GOTA dipole that was there.