Slot Antenna
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2 Meter Slot-Cube Antenna (QST Jan 2019)
Displaying 1-15 of 39
| Dec 9th 2018, 13:19 | |
K1AWCJoined: Nov 7th 2014, 13:42Total Topics: 0 Total Posts: 0 | I would like to know/hear, if anyone has read/built the Antenna in the January QST (Pages 35-36). Please tell me if the dimensions for the antenna are correct. I can't get it to 'Fit'. |
| Dec 11th 2018, 17:46 | |
K1AWCJoined: Nov 7th 2014, 13:42Total Topics: 0 Total Posts: 0 | I was contacted by John, that the short horizontal is 6'(2) Each.. |
| Dec 14th 2018, 10:21 | |
aa4pfJoined: Jan 4th 2012, 01:26Total Topics: 0 Total Posts: 0 | I'm working on building the antenna. I sent John an email suggesting some more details. So far the measurements are OK except that I've had to make the top short horizontal that comes off the top tee about 5 3/8' and the bottom one about 6' to fit better. I've also made up 1' stubbs to connect the tees to the elbows on the 7' vertical. I'm concerned about overheating the CPVC coupling when I solder the last fittings for that mesh. I intend to solder up that section of the antenna first. I'm enjoying the project and look forward to replacing my J-pole. |
| Dec 22nd 2018, 15:02 | |
KD0MQOJoined: Sep 7th 2010, 14:01Total Topics: 0 Total Posts: 0 | Thanks guys. I had the same questions. |
| Dec 22nd 2018, 16:45 | |
n6lgbJoined: Apr 1st 2016, 01:16Total Topics: 0 Total Posts: 0 |
Wrap a wet rag around the CPVC coupler to sink the heat while soldering. |
| Dec 24th 2018, 08:33 | |
K2HYDJoined: Apr 4th 1998, 00:00Total Topics: 0 Total Posts: 0 | I've built one. Only problem I had is that I should have made the 1' pieces that connect the L's to the T's a bit shorter, or maybe I could have jammed the L's and T's closer together. I had about a 3/16in gap between L's and T's, and this pushed the vertical sections up against each other. I held them apart temporarily with a piece of scrap metal when mounting them to the PVC pipe (there was enough 'give' in the whole assembly to allow this). Once mounted and held in place with screws and nuts I could remove the scrap metal piece and everything looks good. |
| Dec 25th 2018, 15:00 | |
K1AWCJoined: Nov 7th 2014, 13:42Total Topics: 0 Total Posts: 0 | 4 Each 8.5' 2 Each 8' 2 Each 7' 2 Each 6' 2 Each 3.5' 2 Each 1' Gap in CPVC connector is 1/8' 10 Each 90* Elbow 2 Each 'T' Fittings |
| Dec 27th 2018, 11:23 | |
KI5BWVJoined: Oct 18th 2018, 10:44Total Topics: 0 Total Posts: 0 | Interesting looking project as I live in a restrictive HOA. Has anyone completed the project and measured the gain and SWR? The SWR appears to be low (Figure 2 in the article) but I was unable to determine the projected gain. |
| Dec 27th 2018, 11:57 | |
KC8THCJoined: Apr 5th 2018, 08:41Total Topics: 0 Total Posts: 0 | And so we add 2 more pieces of 6 inch pipe. Where do they go? Wow. This isn't going to be anything to teach in the antenna class I see. |
| Dec 27th 2018, 12:53 | |
K1AWCJoined: Nov 7th 2014, 13:42Total Topics: 0 Total Posts: 0 | Looking DOWN at the antenna, North has 1 Each 8.5' West has 1 Each 8.5' East has 1 Each 8' South has 1 Each 6',a 'T' fitting, and 1 Each 1'. (2 Sets/N,E,W,S) Stack them Vertical with the 2 Each 7'. |
| Dec 27th 2018, 19:09 | |
KC6ZBEJoined: Jul 16th 2010, 02:31Total Topics: 0 Total Posts: 0 | Started to build this yesterday and noticed it didn't 'come together' as specified in the article. Glad I found I wasn't the only one! Finished the antenna today with the updated dimensions and I am resonant at 152.4 mhz. Checking the 2 meter portion gives me a SWR of 4.2 It was a fun build, but just curious how your guys' cube came out. Dave |
| Dec 28th 2018, 19:56 | |
AD6ZHJoined: Jul 16th 2001, 00:00Total Topics: 0 Total Posts: 0 | I built as in the article. I bored the T connector on a lathe so it could be adjusted. Best swr was with the T touching the elbow. It resonated at about 150mhz. I reheated joints a pair at a time, bumping with a hammer to extend about 1/4 inch in 3 places. This added about 3/4 to 1 inch to the length of a loop. That brouht resonance to 146, and gave a little more separation to the ends. Took a while to get there, but passed all the on the air tests sitting on a wooden table. I don't have an antenna range, so can't say what the gain is. Feels like 5-6 db. A bit lower than a 5/8 jpole, but much better than a rubber duck. Next step is to try it on the car roof to see what a metal plane does to it.. |
| Dec 31st 2018, 13:51 | |
K1AWCJoined: Nov 7th 2014, 13:42Total Topics: 0 Total Posts: 0 | I can't give a full report...yet, But this antenna is turning into 'FRANKNTENNA'. I've made some mods (I will tell more when finished), But I'm still liking this as a portable trip/field antenna. I can hit Repeaters 37 Miles away (MFJ-1918ex 10' stand, Cheap RG58 coax, and a 4 Watt Baofeng UV5-R). Not bad for a start....more to come |
| Jan 1st 2019, 14:32 | |
K1AWCJoined: Nov 7th 2014, 13:42Total Topics: 0 Total Posts: 0 | I spent the day trying different things, and found using 75 Ohm Video Coax dropped the SWR's from 2.4+ (RG-58) to 1.2 !! Runs good SWR's thru the whole Band. I might just be done testing things, this is all I need for my uses. THANKS JOHN, for another GREAT Antenna! |
| Jan 16th 2019, 15:02 | |
N7LTJoined: Apr 4th 1998, 00:00Total Topics: 0 Total Posts: 0 | I started to build this antenna from the article and upon dry fitting the copper fittings, found nothing was coming together properly, Started searching the net and found this form but still have questions... K1AWC, what mods did you make? You never elaborated on them other than changing the coax to 75 ohm. Did anybody find out why the dimensions are so different than the article? KC6ZBE, your initial resonance at 152Mhz is a LONG way off from the ham band. Did you readjust the size to reach resonance on 2 meters? if so, what are your final measurements? AD6ZH, you said you increased the loop by 1 inch. What were your final dimensions for the loops? Any change to the vertical copper? Thanks for your help guys! de N7LT |
Amazon.com: slot antenna. Skip to main content. Try Prime EN Hello, Sign in Account & Lists Sign in Account & Lists Orders Try Prime Cart. The waveguideSlotted object creates a slotted waveguide antenna. There are different types of slotted waveguides, including longitudinal slots, transversal slots, center inclined slots, inclined slots, and inclined slots cut into a narrow wall. A slot antenna is a narrow rectangular opening in a large conductive surface, such as a TV satellite dish. Slot antennas are familiar in the commercial radio world, but not to hams. They’re common in TV broadcasting, the skin of aircraft and in radar, microwave and cell phone applications. This disguised TV dish slot is equal to a J-pole. In this video, i have explained Slot Antenna by following outlines:1. Basics of Slot Antenna3. Structure of Slot Antenna4. Operation of Slot A.
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Displaying 1-15 of 39
I decided to use Westflex 103 cable without a connector at the slot antenna to reduce losses and because all the problems that I had over the years had come from faulty connectors. An N socket could be fitted if preferred and does help reduce any pulling from the weight of cable. The pipe was 35mm x 900mm. Can be 600mm upwards.The length of the tube beyond the slot is not important, in fact other aerials can be attached to the pole away from the slot. The Westflex 103 is too large for 15mm pipes where Quickform 141 or other semi-rigid etc is more suitable.
Due to the hard copper of the pipe I used there appeared to be no bowing at the centre of the slot, but cable ties would be useful if soft copper is found to 'bow' at the centre..
Weatherproofing: PVC pipe is likely to worsen SWR & needs to be >3 times the diam of the pipe and as thin as possible. I used black DPC sheet and PVC tape instead. They worked really well. I have tried EcoFlex 10 instead of Westflex. The flexability of the Ecoflex comes partly from its thinner sheath. This makes cutting slits a little more tricky than the firmer Westflex and means that care is needed as the cable is bent before connecting to the solder tags. Otherwise it seems a good alternative.
If you do make one of these slot antenna please let me know how you get on and I will pass on the info here for others to read. If you wish to keep the visibility of your antennas to a minimum I recommend that you consider making the Bassoon.
Due to the hard copper of the pipe I used there appeared to be no bowing at the centre of the slot, but cable ties would be useful if soft copper is found to 'bow' at the centre..
Weatherproofing: PVC pipe is likely to worsen SWR & needs to be >3 times the diam of the pipe and as thin as possible. I used black DPC sheet and PVC tape instead. They worked really well. I have tried EcoFlex 10 instead of Westflex. The flexability of the Ecoflex comes partly from its thinner sheath. This makes cutting slits a little more tricky than the firmer Westflex and means that care is needed as the cable is bent before connecting to the solder tags. Otherwise it seems a good alternative.
If you do make one of these slot antenna please let me know how you get on and I will pass on the info here for others to read. If you wish to keep the visibility of your antennas to a minimum I recommend that you consider making the Bassoon.