Sir, I just love you practical approach, a joy to watch, the measurements don't lie. Fascinating that PVC pipe is RF 2.4GHz transparent. Thank you kindly.
You have had that Collins RF amp for a long time then ;) I am really lucky in regard to dishes and Grid Packs......I think I would have at least 50 of them....different sizes and configurations, from 6m down to about 8 inches or so......I must get back to playing with them one day...
18:23 Maybe cantenna feed gives better VSWR with parabolic TV dishes where focal point is on side, not exactly in the center of dish. With focal point out of center there are no parasitic reflections between dish and cantenna. Original LNB unit is something like cantenna too, it's best feed for satellite dishes I believe.
ElPaso TubeAmps Thank you for all the good information. It seems that the cantenna is a real winer ! BTW I noticed that you don't have the impedance matching radial screws anymore, are they not needed?
The screws are really not needed but can be used to match it perfectly. I have to agree that the cantenna type antenna is amazing. I took the big black dish to the mountain side in El Paso and I could see lots of access points in every direction but none that were open. I suppose the open ones in businesses like McDonalds, for example, are pretty weak and enclosed in the building. I used the slotted line as the feed in this antenna as it seems to be within about 2 dB of the can feed horn and the output comes straight out the back of the dish were I directly connected the AP via a SMA to N connector and it also looks so much better than the big piece of coax that has to come off the can. Thanks for your kind comments.
What about mounting the cantenna on the back of the dish and use three struts to hold a small sub reflector so the signal get sent down through the dish to the cantenna aka Gregorian Dish antenna
I would love it but I don't have the hyperbolic reflector. I understand that Cassegrain/Gregorian antennas are about 70% efficient so I would need a bigger dish. The difference in the two antennas is that one uses the concave hyperbolic reflector and the other used the reflector in convex configuration. As I understand it, the dish should be at least 10 wavelength which is what the black dish is at 2.4 GHz. Maybe someday I will run across a 6 foot Gregorian/Cassegrain antenna at an estate sale for a couple of dollars.
Is the large mast-mounted parabola you made for 2.4 GHz or was it something else? Do you think it would've worked if it were a factory manufactured C-band mesh dish?
Not sure what the original use for the large black dish was but here is a link to gain formulas. C band being 4-8 GHz, I would think a dish this size would work pretty well. It had gain at 2.4 GHz especially with the 46 ounce bean can for a feed horn. www.electronics-notes.com/articles/antennas-propagation/parabolic-reflector-antenna/antenna-gain-directivity.php
I agree with you, Nick. Just recently, I installed two 5 GHz dishes to have Internet access at my mother-in-laws house and the performance is fantastic. I get 100 MB download here off cable and I get around 95 MB performance at the other end of the 5 GHz link. Everything is built into the probe at prime focus of the dish and is powered over the CAT-5 cable.
I don't know exactly the size but at least half the size of the smallest one in this video. I would guess 0.5 meter across. Very pleased with them. I don't remember the exact model but it is by this company and very similar to the link below. www.balticnetworks.com/ubiquiti-antenna-5ghz-30dbi-light-weight-dual-pol-parabolic-rocketdish.html?gclid=EAIaIQobChMIs_idq-CD2gIVgz2BCh2R4gIoEAQYASABEgKNrPD_BwE
Sir, I just love you practical approach, a joy to watch, the measurements don't lie. Fascinating that PVC pipe is RF 2.4GHz transparent. Thank you kindly.
You have had that Collins RF amp for a long time then ;)
I am really lucky in regard to dishes and Grid Packs......I think I would have at least 50 of them....different sizes and configurations, from 6m down to about 8 inches or so......I must get back to playing with them one day...
18:23 Maybe cantenna feed gives better VSWR with parabolic TV dishes where focal point is on side, not exactly in the center of dish. With focal point out of center there are no parasitic reflections between dish and cantenna. Original LNB unit is something like cantenna too, it's best feed for satellite dishes I believe.
ElPaso TubeAmps Thank you for all the good information. It seems that the cantenna is a real winer !
BTW I noticed that you don't have the impedance matching radial screws anymore, are they not needed?
The screws are really not needed but can be used to match it perfectly. I have to agree that the cantenna type antenna is amazing. I took the big black dish to the mountain side in El Paso and I could see lots of access points in every direction but none that were open. I suppose the open ones in businesses like McDonalds, for example, are pretty weak and enclosed in the building. I used the slotted line as the feed in this antenna as it seems to be within about 2 dB of the can feed horn and the output comes straight out the back of the dish were I directly connected the AP via a SMA to N connector and it also looks so much better than the big piece of coax that has to come off the can. Thanks for your kind comments.
What about mounting the cantenna on the back of the dish and use three struts to hold a small sub reflector so the signal get sent down through the dish to the cantenna aka Gregorian Dish antenna
I would love it but I don't have the hyperbolic reflector. I understand that Cassegrain/Gregorian antennas are about 70% efficient so I would need a bigger dish. The difference in the two antennas is that one uses the concave hyperbolic reflector and the other used the reflector in convex configuration. As I understand it, the dish should be at least 10 wavelength which is what the black dish is at 2.4 GHz. Maybe someday I will run across a 6 foot Gregorian/Cassegrain antenna at an estate sale for a couple of dollars.
Is the large mast-mounted parabola you made for 2.4 GHz or was it something else? Do you think it would've worked if it were a factory manufactured C-band mesh dish?
Not sure what the original use for the large black dish was but here is a link to gain formulas. C band being 4-8 GHz, I would think a dish this size would work pretty well. It had gain at 2.4 GHz especially with the 46 ounce bean can for a feed horn.
www.electronics-notes.com/articles/antennas-propagation/parabolic-reflector-antenna/antenna-gain-directivity.php
far better to dispense with lengthy coax, mount the dongle as close to the can as possible and use a powered usb extension lead.
I agree with you, Nick. Just recently, I installed two 5 GHz dishes to have Internet access at my mother-in-laws house and the performance is fantastic. I get 100 MB download here off cable and I get around 95 MB performance at the other end of the 5 GHz link. Everything is built into the probe at prime focus of the dish and is powered over the CAT-5 cable.
wonderful, how bigis the dish?
I don't know exactly the size but at least half the size of the smallest one in this video. I would guess 0.5 meter across. Very pleased with them.
I don't remember the exact model but it is by this company and very similar to the link below.
www.balticnetworks.com/ubiquiti-antenna-5ghz-30dbi-light-weight-dual-pol-parabolic-rocketdish.html?gclid=EAIaIQobChMIs_idq-CD2gIVgz2BCh2R4gIoEAQYASABEgKNrPD_BwE
so about 18 ins, thanks
The stressed parabola didn’t work? Aww that’s what I was going to try.