2 Meter Slot-Cube Antenna (QST Jan 2019)
| Feb 13th 2019, 09:28 | |
jimvw57Total Topics: 0 Total Posts: 0 |
I believe different brands of the copper connectors are not all the same length. kmikemoo did that change the gap between the vertical tubes? |
| Feb 16th 2019, 23:06 | |
jimvw57Total Topics: 0 Total Posts: 0 |
did some more playing around today and found that by moving the feed point to 4 inches back from the vertical l, I get resonance at 148 Mhz with SWR at 1.3. I attached wire directly to the horizontal tube without using the short stubs with the tee connectors UPDATE I took it outside and stuck it in a tree about 6 1/2 ft off the ground, reports from other stations say it is much better than my od J-Pole and lots less background noise, I noticed it also doesn't feedback into my computer speakers. |
| Feb 26th 2019, 20:32 | |
kmikemooTotal Topics: 0 Total Posts: 0 |
jimvw57 I didn't change the vertical spacing (which I assumed was the 7" pieces). I just expanded the two squares. I also tried moving the t stubs away from the verticals with the original lengths and I'm pretty sure that my resonant frequency went up. I have yet to put mine on the air. Snow and cold are winning. |
| Mar 2nd 2019, 16:31 | |
jimvw57Total Topics: 0 Total Posts: 0 |
same as what I found. |
| Mar 11th 2019, 06:04 | |
hartfordTotal Topics: 0 Total Posts: 0 |
I built the antenna over the past couple of weekends and found that mine also was resonant at 152 MHz. I lengthened two of the horizontal pipe sections 1 1/4" each and the resonant frequency dropped to 146 MHz. The SWR is below 1.3:1 across the band. I also abandoned the CPVC coupling for two copper end caps, this gives a little more metal to tap into for the coax connection. I would also like to try this antenna as a mobile as suggested by AD6ZH, and would like to know if anyone has tried it over a ground plane. |
| Apr 17th 2019, 00:01 | |
KC6ZBETotal Topics: 0 Total Posts: 0 |
Sorry for the late response, OM. I see a lot of other people got their cube resonant somewhere in the 150mhz range as well with the original specs. I tried the heating up/hammering out method but gave up. I decided to try to make a new one using K1TGF's dimensions. I like the idea of how he added some length on some sides. Got a few more pieces to solder and we will see how it goes. |
| Apr 17th 2019, 19:56 | |
KC6ZBETotal Topics: 0 Total Posts: 0 |
SUCCESS! Using K1TGF's dimensions, the new one I built came out resonant enough in the 2 meter portion with an SWR of 1.4 at 146.500 mhz which is just fine by me. Also, instead of screwing in the feed line to the stubs, I used 3/4in copper pipe strap and wraped it around the 1/2in stubs and secured it with a bolt (if that makes sense). 73 Dave. |
| Apr 21st 2019, 18:13 | |
jimvw57Total Topics: 0 Total Posts: 0 |
I used hose clamps so I could adjust where they are positioned. Easier to tune |
| Apr 30th 2019, 10:19 | |
KG7QJBTotal Topics: 0 Total Posts: 0 |
My swr came out 1.4 at 146.520 using 50 feet of LMR 400 and 5 wraps of choke using a smaller coax on the plastic gray pipe (electrical pvc) . Very impressed with it , works as it should. My pictures are on QRZ.com not sure how to get a picture on here. KG7QRZ Curtis in Pasco, Washington. P.S. some of the lengths were wrong on the copper pipe, figured it out pretty quick that something was wrong. |
| Jul 15th 2022, 15:25 | |
jimvw57Total Topics: 0 Total Posts: 0 |
after over 3 years of weekly use, the only thing I found needed was to clean up the contact points and added a hole to drain water out of the tubes. Not sure how it gets in there but it has a way out now. When i see the SWR go up, it is time to clean up the contact points for the cable connections. |
| Jan 28th, 14:01 | |
jimvw57Total Topics: 0 Total Posts: 0 |
Update** Still using this lil guy at least weekly, I did change and added it to the top of a 40 ft tower, Still getting reports of clear transmissions up to 50 plus miles away. |
| Aug 20th, 22:48 | |
jimvw57Total Topics: 0 Total Posts: 0 |
Been a while since I was in here, my antenna is now (and has been) up near the top of my 37 Ft tower, and has been working great! I get reports weekly of being able to hit a repeater 40 plus miles away with good clarity and full quieting. Lots of operators want to copy my setup. Only thing I have changed was to solder the feed points to take care of needing to clean them after being exposed to the elements. |
