The CRES Amateur Radio Club held a meeting over lunch on Wednesday, 16 May 2001. The meeting was called to order by President Gordy Lashley/WD8CZG at 11:40 AM. Those in attendance were: WD8CZG, WB7AIZ, KC8HIH, K8ON, K8TWH, KB8DEO, KA8ZRT, WD8EBS, KD8ZG, K9RV, K8RSP, KD8WK, and special guest Dave Klinect, KA8MHW. The revised minutes from the March meeting were accepted as mailed. The Treasurer reported $928.46 in checking, $23.61 in petty cash, and $40 in undeposited dues. The Treasurer indicated he had renewed the subscription to CQ Magazine, at a cost of $31.95. A brief canvassing of those present revealed that only one member read the magazine regularly. A motion was made and seconded to not renew the magazine next year, and passed. Gordy announced that Jerry Scott/K9RV resigned as Lab Manager, effective 2 May 2001. Gordy indicated that he will work to appoint someone to fulfill the position for the remainder of year. Dave Woolf/K8RSP agreed to chair the Field Day committee. Arg Grandle/ KD8ZG agrred to assist. Dave indicated the main receiver on W8ZPF/R still has problems and will be removed, probably over the weekend of May 25-27th, to allow for bench testing. The repeater will remain on the air, but coverage will be degraded, with only the remote receiver at Dave's house in Pickerington online. [ See below for more information on this. ] Tricia Kovacs/KC8HIH reported that we are getting backlogged with COARES radios which need to be repaired. She requests anyone who could assist give her a call at x5967. Dave Jeffords/K8ON indicated the next Club meeting will be offsite at Universal Amateur Radio. The meeting will be Saturday, June 9th, at 3:30 PM. Universal is interested in hosting the meeting to allow them to showcase the latest ham gear to us. Please try to attend and support the club. There will be door prizes. The meeting was adjourned at 11:55 after which Dave Klinect/KA8MHW from AEP gave an excellent talk on finding and eliminating RF interference from powerlines and gave a tour of the AEP RFI van. Respectfully submitted, Rob Stampfli/KD8WK CRES-ARC Secretary/Treasurer =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= At the request of the President, the following offline items from the previous month are appended to these minutes: From: David E Woolf Date: Wed, 2 May 2001 11:38:10 -0400 Repeater Committee Report 5/2/01 1) Voter - Adjustment on the voter and particularly lowering of audio input levels seem to have corrected both the popping and frying noise on the main and the false voting. The voter appears to be working correctly. 2) Antenna - No progress has been made in getting the tower lowered so we can get the base coil on the main antenna replaced. A new SWR measurement up the feedline after the duplexer indicated a value of 1.6. This seems reasonably in line with the value of 1.8 measured on the roof at the antenna last fall and would indicate no major problems with the feedline or antenna. Never the less we will continue our efforts to get the tower lowered so we can replace the antenna base sometime in the near future. 3) Grounding - This looks to be a dead issue as we cannot seem to get the attention of the facilities people to do anything. 4) Control Receiver - Thanks to the effort KD8ZG and with help of WD8CZG the control receiver is back on-line and functioning. 5) 440 Receivers - Two of the 440 receivers have now been connectorized so they can be easily removed to work on. When convenient to remove the 3rd (Pickerington link) will also be done. Sensitivity was measured on the two rcvrs while they were removed from the repeater: Dublin link = -113dbm (0.5 microvolt) for 20db quieting (currently off-line) Control = -107dbm (1 microvolt) for 20 db quieting The tone decoder on the Dublin rcvr appears to not be working this will be worked on as time permits. 6) Main Rcvr - Work is concentrating right now on determining why the main site seems to have poor rcv sensitivity. Inital measurements point to both a problem in the Motorola receiver as well as the duplexer. Respectfully submitted for the Repeater Committee (K9RV, KD8ZG, K8RSP), Dave - K8RSP From: David E Woolf Date: Wed, 2 May 2001 10:13:29 -0400 I did some measurements on the repeater last night to determine the whether the receive sensitivity at the main site is up to par. For you techies, here is what I found: Rcvr sens. (for 20 db quieting) = 1.23 microvolt Duplxr rcv side cavities: notch @ 146.67 MHz = -76 db insertion loss @ 146.07 MHz = -7 db It appears the maximum notch is not tuned to 146.67 but somewhat higher Duplxr xmt side cavities: notch @ 146.07 MHz = -86 db insertion loss @ 146.67 MHz = -2 db It appears the maximum notch is tuned to 146.07 So it seems we may have multiple problems: 1) The receiver sensitivity with the pre-amp option (which I am told by Gordon we do have) should be 0.25 microvolt. This contributes a loss of -13.8db in sensitivity. 2) The insertion loss on the rcv side is too high. I would expect it to be more like the -2 db measured on the xmit side. This may be improved by tuning but not yet sure. This is contributing -5 db to -7db in lost sensitivity. 3) The notch attenuation is not what we should expect from the cavities. The ARRL FM manual (from which we took the design for the cavities) says we should expect -100 db for each side. I am not sure what this might be contributing to lost sensitivity. From the ARRL FM manual article rule of thumb says that for our xmit power, on rcv side we need about -80 db notch and on the xmit side -100 db notch. We are going to take one problem at a time. First we are going to try and determine why the receiver is out of spec. This could be as simple as a blown pre-amp. After we fix that then we will tackle adjusting the duplexer to optimum. If that fails to be adequate we may want to think about obtaining a new duplexer. The one we have is homebrew and was original with the repeater when we installed it in the late 1970's. Dave - K8RSP From: "Jeffords, Robert David (Dave)" Date: Wed, 2 May 2001 10:14:31 -0400 Status of Program arrangements for CRES ARC: A firm commitment from Fred Osterman for a program featuring new transceivers at Universal Radio has been received for Saturday afternoon, June 9th at 3:30pm. Dave Klinect, KA8MHW, from AEP has tentatively agreed to speak to the CRES ARC on May 16th at 11:30am concerning RF interference, locating methods and equipment. He will bring his van containing his equipment for viewing as well. Expect to confirm or reschedule when I contact Dave next week. Barrie L. Schwartz, AFF1OH/AFA1GE/W3ENL, State MARS Director of Ohio, on April 25, 2001 stated he would not be able to talk with us about MARS programs in our regular lunchtime hours, since he works at DSCC during the day. I queried about alternate hours convenient for him, but have not yet heard back from him. David K8ON From: "Stampfli, Robert E (Rob)" Date: Tue, 1 May 2001 17:51:59 -0400 The auto-reminder function is installed on w8zpf.cb.lucent.com. We'll know Monday the 7th, if it works. At that time, it should "remind" Gordy and me that, in a week, all members will be notified of meeting scheduled for the third Wednesday. Then, if we don't disable it, it should send out the official notice on the 14th. We'll see.... Rob From: David E Woolf Date: Wed, 16 May 2001 13:48:48 -0400 This is an update to my report of 5/2/01. Progress on repeater work: 1) The Dublin Rcvr is now back on line. Tone decoder now works. Turned out to be a bad diode on the tone board. Anyone that would like to try getting into the repeater via this link it is 445.750 using our standard tone of 131.8 Hz. The antenna still points toward Dublin. 2) Main Rcvr: The receiver pre-amp was removed and checked out. It is working to spec after a few adjustments. It actually was not that far off. It has been re-installed. We also discovered that we had a 146.07 crystal filter installed ahead of the pre-amp. I did not realize that they made xtal filters at those frequencies, so I learned something new. Anyway the filter looks OK except that it has -6db of insertion loss. We could find no specs on the filter which was sold by Motorola. That -6db was directly lowering our receive sensitivity so for the moment it has been removed. Current measured sensitivity is 0.84 microvolt, An improvement, but not the 0.25 we should have. All measurements seem to indicate the main receiver is at fault. We plan to remove it next and try to determine what is wrong. This will most likely be done the weekend of May 25-27 Dave Woolf - K8RSP 5/16/01