[sarcmembers] Re: SARC Tower and Dish move...
- From: "John Maetta" <j.maetta@xxxxxxxxxxx>
- To: <sarcmembers@xxxxxxxxxxxxx>
- Date: Tue, 12 May 2009 17:39:59 -0700
Hi George,
Yes, the rotor on the telephone pole does not rotate and we noted that the 2
meter antenna on coax 'B' had 2.5:1 SWR at 144.200. So we have at least two
problems on the pole.
I would sugest that we install a sequencer circuit to properly switch the
preamp into 'bypass', then key the high power amp and finally enabling the
radio's TX. At this power, 'hot' switching any coax relay will quickly shorten
their life or burn them out, I speak from experience on this one. The results
of 'hot' switching can be seen on the relay pieces on the shelf under my 2
meter amp, a rather expensive repair.
Tomorrow I will order two 4 event sequencer kits from W6PQL. One is for another
project of mine and the second will be donated to sequence the IC-736, TE
Systems amp and any preamp we install. I should have these ready for test by
Memorial Day weekend.
The SARC has the makings for a great VHF station with EME capability.
Weak signal VHF station design is not to be rushed...Lets do it right the first
time, I will be glad to help.
73
John
----- Original Message -----
From: george bernard
To: sarcmembers@xxxxxxxxxxxxx
Sent: Monday, May 11, 2009 20:00 PM
Subject: [sarcmembers] Re: SARC Tower and Dish move...
john, i think there is a horiz 2m atenna already on the big mast but the
rotor does not work. it that one corroded also? thank you for providing
yours, should we put a mast mounted preamp on it? we can use the landwehr and
if it doesnt work then i can purchase an AAR model but you need to help me
solve the 300 watt problem. regards, george w6nre
ps: i will be up at the club for 2m ssb nets on wed at 7:30 pm till about
10:30 pm.
want to come up and watch what goes on?
there are two nets, one at 8 and one a 8:30 pm.
santa barbara, ca web page is
www.balanceindustries.com for my company cell 818-370-9407
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From: John Maetta
Sent: Monday, May 11, 2009 5:53 PM
To: sarcmembers@xxxxxxxxxxxxx
Subject: [sarcmembers] Re: SARC Tower and Dish move...
I took the nearly new Cushcraft 13B2 out of my backyard storage shed and
assembled it. Using my backyard test stand, I was able to adjust the SWR to
~1.2:1 @ 144.200Mhz, right at the 2 Meter weak signal calling frequency.
Here are the test photos and the antenna
www.n6vmo.com/arpics/SARCCushcraft13B213ElementYagi/index.html
Just a couple of coats of Krylon just before installing it on the tower and
it should server the SARC very well for several years.
73
John
----- Original Message -----
From: jportune@xxxxxxx
To: David Dowler KA6BFB ; sarcmembers@xxxxxxxxxxxxx
Sent: Monday, May 11, 2009 15:55 PM
Subject: [sarcmembers] Re: SARC Tower and Dish move...
In what state is the 13el 144 beam, up on a tower, down but still
assembled, or disassembled? And what condition is it in? I think Dave Dowler
KA6BFB is the best person to offer it to for the club. See email address above.
TNX John W6NBC
----- Original Message -----
From: Paul Andreasen
To: sarcmembers@xxxxxxxxxxxxx
Sent: Monday, May 11, 2009 3:29 PM
Subject: [sarcmembers] Re: SARC Tower and Dish move...
John, I have an additional 13 element 144 here that isn't being used if
you need it. I haven't come near to getting my antennas back up yet. (give it
another decade)
Paul
At 09:10 AM 5/10/2009, you wrote:
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
To: sarcmembers@freelistsorg
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
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
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