Author Topic: 440 Antenna for VHF contest  (Read 4335 times)

Offline jerseyboy

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440 Antenna for VHF contest
« on: August 16, 2015, 11:04:48 PM »
http://www.fredspinner.com/W0FMS/CheapYagi/vjbcy.html

I am going to try and build an 11 element yagi for the September VHF contest.  I may not have time to travel to the mountains this time but I only have 20 watts ssb on my 897 so I could use all of the gain I can get.

I bought 9 gauge galvanized bare wire at home depot. 50 feet for 11 dollars. The hard part was finding the wire clamps. The funny part was the wire was not in electrical but in the part of the store where fasteners are next to the plain and threaded galvanized bars and screws.

Wish me luck.

Jerseyboy

Offline Carl

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Re: 440 Antenna for VHF contest
« Reply #1 on: August 17, 2015, 06:15:58 AM »
That is a good design with great results and fairly strong, just keep all measurements within 1/16 inch of plan and you will have a great antenna...mine made with 1 inch PVC plastic pipe lasted over a year before the PVC got brittle and gave out.

Offline jerseyboy

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Re: 440 Antenna for VHF contest
« Reply #2 on: September 06, 2015, 09:46:17 PM »
http://www.wa5vjb.com/yagi-pdf/cheapyagi.pdf

Here is a better description of the yagi, especially the driven element.

I have the antenna mostly built except for the feedpoint.  I am going to put a connector on the antenna instead of soldering the coax directly to the driven element.

I will post pictures when I am done... Uh, how do you post pictures?

Jerseyboy

Offline Carl

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Re: 440 Antenna for VHF contest
« Reply #3 on: September 06, 2015, 09:53:47 PM »
I up load to PHOTOBUCKET and it allows you to get a link that posts the photo into the group...there is a thread describing how to do it here on TSP forum.

Offline jerseyboy

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Re: 440 Antenna for VHF contest
« Reply #4 on: September 07, 2015, 08:36:11 PM »
Okay, here is the finished product which is about 5' long mounted on a 1x3.  The elements are galvanized 9-guage wire held on with low-voltage staples (like for CAT3) then encapsulated in RTV silicone.

This is the top


This is the SO-239 and its connection to the driven element


This is the 2" PVC Tee which allows me to choose vertical or horizontal polarization depending on how I attach the 8' 2" PVC pipe


I tested it out with my HT and I was able to hit a few repeaters while the antenna was sitting on my plastic garbage can

All ready to be tested out next weekend for the contest

Jerseyboy

Offline Carl

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Re: 440 Antenna for VHF contest
« Reply #5 on: September 07, 2015, 09:20:13 PM »
It looks GREAT,I could not make measurements but I suspect it will perform well...maybe 7 to 8 DB gain..

Offline jerseyboy

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Re: 440 Antenna for VHF contest
« Reply #6 on: September 08, 2015, 08:20:57 PM »
It looks GREAT,I could not make measurements but I suspect it will perform well...maybe 7 to 8 DB gain..

Thanks Carl.  My goal is to actually make a contact on 440 during the contest.  I haven't made one in the VHF/UHF contest since moving to New Jersey.  No mountaintopping this weekend though.  Maybe January.

Jerseyboy

Offline jerseyboy

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Re: 440 Antenna for VHF contest
« Reply #7 on: September 13, 2015, 03:55:43 PM »
It looks GREAT,I could not make measurements but I suspect it will perform well...maybe 7 to 8 DB gain..

Hey, it worked.  I actually made contacts with this antenna while sitting on my back porch with the antenna on an 8-foot PVC pipe tied to the railing.  If anyone was doubting whether elevation/height makes a difference in VHF/UHF work, well, doubt no longer.  Most of New Jersey is in the Coastal Plains and rarely gets 100 feet above mean sea level.  The 1500+ feet of elevation I had for the June contest was awesome.

Also, I now have a reason to make a better 2m yagi.  Mine came crashing down and split the boom.  I turned around to get some rope to tie if off and down it came.  I spent 30 minutes this morning trying to patch it up well enough to put it into service.  It must have worked since it was the band I did most of my contacts on.  Definitely need a new one now.  Hey, any excuse to make a new antenna.

Oddly enough, the 440 yagi played nice with my radio while on 2m.  I didn't make any contacts with it but it had low enough SWR that I was able to push 50 watts through it.

Jerseyboy

Offline Carl

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Re: 440 Antenna for VHF contest
« Reply #8 on: September 13, 2015, 04:58:18 PM »
 :clap:

Great work.

Offline TiredOldGrunt

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Re: 440 Antenna for VHF contest
« Reply #9 on: September 13, 2015, 05:00:47 PM »
440 is UHF not VHF so I am confused with what you want...  Carl must understand though...
TOG

Offline Carl

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Re: 440 Antenna for VHF contest
« Reply #10 on: September 13, 2015, 05:23:27 PM »
440 is UHF not VHF so I am confused with what you want...  Carl must understand though...
TOG

He made antennas for BOTH BANDS and the VHF broke...but he put it back together.UHF apparently performed well.

Offline jerseyboy

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Re: 440 Antenna for VHF contest
« Reply #11 on: September 13, 2015, 08:29:01 PM »
He made antennas for BOTH BANDS and the VHF broke...but he put it back together.UHF apparently performed well.

Yes.  I had a 2m yagi I built a few years ago and I just built a new 70cm yagi for the contest this weekend.  While setting up both antennas, the 2m yagi fell and split the boom and some elements fell off.  I had to fix it quickly as I only had so much time dedicated to operating the contest.  While jumping up bands to get a 440MHz contact after meeting on 144MHz, I had to switch antennas to the 440MHz antenna.  Before switching back, I tested the 440MHz yagi on 144MHz.  Oddly enough it had a low SWR (~1.4:1) as reported by the radio and I was able to push most of the 50 watts (as reported by the radio) out of the new antenna on a band it was not designed for.

The fun part is working other operators on equipment you made.  Something very pleasing about that.  Also, it adds something to the skills list as an added benefit.  Also, I was just reporting progress, not asking a question.  Also trying to spur some interest in Ham Radio by hopefully showing something interesting to the others.

Jerseyboy