Please, endure an opinion. I have never been a fan of log periodic antennas. They yield relatively poor gain compared to yagis. Yes they have great bandwidth, but that bandwith has a BIG down side. It naturally causes MUCH more front end overload than an equivalent tuned antenna onone band. Therefore, if broadband is desired for a general puprose testing antenna, that big discone Dave recovered is probably as good a compromise. If one needs gain, then go to a yagi or a quad, not a log periodic. So much for mouthing off. So if we can repair this one, fine, in my not-so-humble opinion, I personally wouldn't spend money on a replacement that won't really give us that much performance. As we all know, even a dummy load "gets out," and I suppose some ham has gotten his DXCC on one.
John W6NBC----- Original Message ----- From: "Eric Lemmon" <wb6fly@xxxxxxxxxxx>
To: <sarcmembers@xxxxxxxxxxxxx> Sent: Sunday, May 10, 2009 6:29 PM Subject: [sarcmembers] Re: SARC Tower and Dish move...
Dave, Thank you for bringing your antenna-repair expertise to bear on the log-periodic problem. I guess we should not be surprised that antennas donot last forever in this climate! When we dismantled the Wilson tri-banderfor PM, several years ago, we found a lot of corrosion and loose connections. Not many antennas are built well enough to "install and forget." 73, Eric Lemmon WB6FLY -----Original Message----- From: sarcmembers-bounce@xxxxxxxxxxxxx [mailto:sarcmembers-bounce@xxxxxxxxxxxxx] On Behalf Of David Dowler Sent: Sunday, May 10, 2009 5:37 PM To: sarcmembers@xxxxxxxxxxxxx Subject: [sarcmembers] Re: SARC Tower and Dish move... John I went up and played a bit with the log periodic today. The connection to the coil in back were corroded beyond belief. A quick check with an ohm meter showed one side was totally floating. I finally got the coil off and spent some time cleaning the connections, and put it back together. The I discovered the the place where the feedline actually meets the antenna had a bad press fit. I cleaned that up but I could tell the connection was intermittent. since the press fit was with copper, I dabbed a little solder on the other side of where it was fitting. I knew I could not solder the aluminum, I was just trying to temporarily make a connection of any kind to the center of the feed line. It worked and the connection was constant, and the SWR was constant, but it was constantly bad. It now worked in the 440 Mhz and (which it did not before I started) with a good SWR, but it was not happy on 2M or 6M. That is where I left it. I might return to it later. George was discussing getting a new antenna while I was there, so I'll see what happens. Dave John Maetta wrote:George, With all the amateur expertise we have in our club, troubleshooting the log periodic should be easy, so there is no need to order a new one. Let us know how you net activity goes. 73 John ----- Original Message ----- From: "george bernard" <gbernard@xxxxxxxxx> To: <sarcmembers@xxxxxxxxxxxxx> Sent: Sunday, May 10, 2009 9:32 AM Subject: [sarcmembers] Re: SARC Tower and Dish move...fyi, i have located the create log periodic in a catalog and it is now only $450. it advertises a 10-12 db gain with a 15db front to back ratio. i am willing to order another one tomorrow from henry radio and have it sent for assy and install if the club techs think it is worth doing. i am going to the club today with my mfj and try to size things up again. my cell is 818-370-9407 , bob harrison is supposed to be going up , too. i will try to run the ft-736 barefoot this evening from the position by the refrig with beam ese and see if i can get into the LA and SD nets on 144.240 at 8 PM. george w6nre santa barbara, ca web page is www.balanceindustries.com for my company cell 818-370-9407 -----Original Message----- From: Eric Lemmon Sent: Sunday, May 10, 2009 9:22 AM To: sarcmembers@xxxxxxxxxxxxx Subject: [sarcmembers] Re: SARC Tower and Dish move... John, We have plenty of 9914- the new stuff we got from DRMO- to add more feedlines. I have a water-cooled core drill to make some additional penetrations, not only on the west side for the dish system, but also a few more into the radio room and the workshop. I am awaiting delivery of a special adapter to connect a 2.5" core drill to my water injection swivel. It should be delivered within a week. 73, Eric Lemmon WB6FLY -----Original Message----- From: sarcmembers-bounce@xxxxxxxxxxxxx [mailto:sarcmembers-bounce@xxxxxxxxxxxxx] On Behalf Of John Maetta Sent: Sunday, May 10, 2009 9:10 AM To: sarcmembers@xxxxxxxxxxxxx Subject: [sarcmembers] Re: SARC Tower and Dish move... I agree with John P.'s assessment and propose the following: In an effort to get the SARC on the 6 meter band, I will donate a 5 element 50MHz yagi to install on the portable roof tower. Along with that, I will donate a Cushcraft 13B2 144MHz yagi for the portable roof tower. We can troubleshoot the log periodic at our leisure, and reinstall it if decided. I will have a day or so over the Memorial Day weekend and will try to get the two antennas (50Mhz and 144MHz) mounted and tested. Hopefully, I can have it ready and use the station on 50MHz during the June VHF contest. If someone has a 220Mhz yagi, now would be a good time to get it mounted too. Does the SARC have enough 9913 or equivalent to make another run or two up to the portable tower? Is the radio room penetration have enough room for another coax or two? In addition, we noted that SARC's the horizontal 144MHz, on coax 'B' exhibited 2.5:1 SWR at 144.200MHz. Something else to troubleshoot in the future. 73 John ----- Original Message ----- From: jportune@xxxxxxx To: sarcmembers@xxxxxxxxxxxxx Sent: Sunday, May 10, 2009 8:30 AM Subject: [sarcmembers] Re: SARC Tower and Dish move... My phone is 805-406-6176. But on a conventional SWR bridge you should not be getting high SWR. So if you are, you do have a problem which is not due to the basic design of the antenna. Other than that I really do not have any other suggestion. Call if you wish, though. John W6NBC ----- Original Message ----- From: george bernard <mailto:gbernard@xxxxxxxxx> To: sarcmembers@xxxxxxxxxxxxx Sent: Sunday, May 10, 2009 8:26 AM Subject: [sarcmembers] Re: SARC Tower and Dish move... john, i think you are correct. can you call me on home fone? 805-688-6324 and we can discuss what to do about this $1500 antenna? how do we use it? do we just have to tolerate the high swr? george santa barbara, ca web page is www.balanceindustries.com for my company cell 818-370-9407 ________________________________ From: jportune@xxxxxxx Sent: Sunday, May 10, 2009 8:22 AM To: sarcmembers@xxxxxxxxxxxxx Subject: [sarcmembers] Re: SARC Tower and Dish move... Rember basic radio theory. A log-periodic is basically a NON-resonant antenna. So "some" instruments may not see it correctly. But on a basic SWR bridge is should show low SWR on any requency within its range. ----- Original Message ----- From: george bernard <mailto:gbernard@xxxxxxxxx> To: sarcmembers@xxxxxxxxxxxxx Sent: Sunday, May 10, 2009 8:09 AM Subject: [sarcmembers] Re: SARC Tower and Dish move... john, do you think that a log periodic antenna might not resonate on any ham bands? it is covering 50-1300 mcs so maybe it doesnt dip like we expected it to on 144.2? perhaps i should just call ted henry at hrc and purchase a 15 element yage for that tower/rotator and call it quits with the log periodic? it worked fine for me in goleta on six and two meters and also on 432.12 ssb. thank you for donating the use of your 70 amps for this rig. we need to tell all members not to run power up past 300 watts as you recommend and also how do you want to proceed on the landwehr preamp which is in the workshop area? btw i got the ultrasonic bird repeller installed in my airplane hangar at smx airport yesterday. it is made by Bird-X.com company of chicago, cost was only $249. regards, george bernard w6nre PS: the photo of the explorer sheriff scouts who are using my donated "black box uhf radios" on 460.275 and .325 were useful by visiting police officers from other jurisdistricts working the fire. sheriff brown allowed us to program channels 1-7 to the same freqs as the regular motorolas which his peole carry. i bought 24 of them and a computer to program the freqs. channels 8-16 are gmrs channels for the kids to talk with each other. these are only $150 each so if they fail we delete the serial number and trash the radio. if one gets lost we dont worry about it. santa barbara, ca web page is www.balanceindustries.com for my company cell 818-370-9407 ________________________________ From: John Maetta Sent: Sunday, May 10, 2009 7:22 AM To: sarcmembers@xxxxxxxxxxxxx Subject: [sarcmembers] SARC Tower and Dish move... All, Yesterday, with the help of Bob, W6RFH, we were able to reposition the EME dish and portable tower. The new locations allow much shorter control and hardline runs to the operating positions. My special thanks to Bob, for his expertise in delicately moving of the fully loaded EME tower. www.n6vmo.com/arpics/SARCTowerandDishMoveMay92009/index.html I have loaned SARC the use of my Astron RS-70 powersupply to power the TE Systems 144MHz amplifier. It is modified to power and provide cooling air to the amplifier. Later, W6NRE arrived and we discovered during testing, that the log periodic antenna exhibited high SWR on 144.200MHz We also noted that the antenna was not resonate on any amateur band or frequencies in the VHF range. The log periodic antenna was taken down for further troubleshooting and the tower is currently laying flat on the SARC roof. The 1.29GHz amplifer has new cooling water and tested to 200 watts output, it should be ready for 1.2Ghz EME operation by June 6th. Hopefully, after the monthly meeting, it can be successfully demonstrated by providing our first 1296MHz EME contact. This past week, I noted an ad on QTH.com for a almost new 12' parabolic TVRO dish. The dish is for sale and located in Solvang. I emailed the seller and asked if he had not sold it, would he be interested in donating it to the club. He happily agreed. If it becomes available, and meets with the board's approval, along with focal and mounting requirements, I will meet with him to transport it to the club, swap it out with the current 10' dish. The 10' dish will then leave for the dump, unless a club member wants it. The new dish will provide ~50% more reflective surface area than the 10' dish. This extra surface area will add ~2.8dB of gain, effectively almost doubling the ERP and adding ~1/2 S-Unit of received signal strength. 73 John _______________________________________________ You have received this because you are subscribed to the Satellite Amateur Radio Club Members Mailing List To post on the mailing list, simply send email to sarcmembers@xxxxxxxxxxxxxx This mailing list will only accept email from subscribed members so SPAMMERS will not get your email address To unsubscribe, send an email to sarcmembers-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field OR by logging into the Web interface at: //www.freelists.org/cgi-bin/lsg2.cgi _______________________________________________ You have received this because you are subscribed to the Satellite Amateur Radio Club Members Mailing List To post on the mailing list, simply send email to sarcmembers@xxxxxxxxxxxxxx This mailing list will only accept email from subscribed members so SPAMMERS will not get your email address To unsubscribe, send an email to sarcmembers-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field OR by logging into the Web interface at: //www.freelists.org/cgi-bin/lsg2.cgi_______________________________________________ You have received this because you are subscribed to the Satellite Amateur Radio Club Members Mailing List To post on the mailing list, simply send email to sarcmembers@xxxxxxxxxxxxxx This mailing list will only accept email from subscribed members so SPAMMERS will not get your email address To unsubscribe, send an email to sarcmembers-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field OR by logging into the Web interface at: //www.freelists.org/cgi-bin/lsg2.cgi_______________________________________________ You have received this because you are subscribed to the Satellite Amateur Radio Club Members Mailing ListTo post on the mailing list, simply send email to sarcmembers@xxxxxxxxxxxxxxThis mailing list will only accept email from subscribed members so SPAMMERS will not get your email address To unsubscribe, send an email to sarcmembers-request@xxxxxxxxxxxxx with'unsubscribe' in the Subject field OR by logging into the Web interface at://www.freelists.org/cgi-bin/lsg2.cgi _______________________________________________ You have received this because you are subscribed to the Satellite Amateur Radio Club Members Mailing ListTo post on the mailing list, simply send email to sarcmembers@xxxxxxxxxxxxxx This mailing list willonly accept email from subscribed members so SPAMMERS will not get your email addressTo unsubscribe, send an email to sarcmembers-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field OR by logging into the Web interface at: //www.freelists.org/cgi-bin/lsg2.cgi
_______________________________________________ You have received this because you are subscribed to the Satellite Amateur Radio Club Members Mailing List To post on the mailing list, simply send email to sarcmembers@xxxxxxxxxxxxxx This mailing list will only accept email from subscribed members so SPAMMERS will not get your email address To unsubscribe, send an email to sarcmembers-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field OR by logging into the Web interface at: //www.freelists.org/cgi-bin/lsg2.cgi
