I have a background in Amateur (HAM) Radio and have been thinking about this topic for some time. More recently I found myself standing in the toy aisle of my local Cheap Shop - the one like Ali Baba's Cave full of imports - staring at frisbees wondering. Two frisbees ($4) glued together would make an excellent low drag aerodynamic disc for an RV TV Antenna. Here's what I have come up with in a step by step home brew DIY project that will save your pocket hundreds.
Step 1. Measure three lengths of soft wire - I used some old power cord - measured and cut to be resonant on three Australian UHF TV frequencies - that is 550Mhz = 54cm, 650Mhz = 46cm, and 750Mhz = 40cm - which will give you three loops to glue inside the bottom frisbee.
Step2. Purchase a TV Balun* ($5) from Jaycar or eBay and glue it to the bottom frisbee with the ends near the outside circumference and join the three loops to the Balun.
*A Balun is a matching transformer that matches a balanced loop antenna to unbalance coax cable - balanced to un-balanced, hence the name Balun.
Step 3. Drill a small hole in the center of the bottom frisbee and feed a length of RG6 (or RG59) coax cable through the hole. The cable should be long enough to stretch from wherever you decide to mount the final assembly to the through panel connector or whatever/whichever method you decide to get the coax cable inside the RV. On the frisbee end you will need to connect the coax cable to to the Balun via a F-Type coax cable connector or similar. Again Jaycar and crap bay have these cheap as chips.
Step 4. Build a riser/mount assembly and fit the frisbee to the mount. I suggest you use two PVC floor drain flanges from Bunnings (less then $5 for the pair) and a short length of 50mm PVC plumbers tube for another couple of dollars to join the two flanges. You choose the height by the length of the 50mm tube; I would suggest the entire height be around 15cm. Then glue and bolt the bottom frisbee to the top flange with at least 4 small stainless bolts nuts and washers and snot it up with some Sika or good quality silicone to keep the water out. You decide whether to drill a small hole for the coax cable to feed through the flange mount riser assembly or whatever way you choose to feed the cable from outside.
Step 5. Glue the top frisbee with some super glue or very good quality two pack epoxy and seal the entire circumference with Sika or silicone to keep out the moisture and or rain.
About this time you should have a disc mounted to the two flanges such that it resembles a store bought RV Disc Antenna.
Step 6. Mount the whole assembly to the roof of the RV - this is entirely your decision as to how and where you want to put it. Try to give it clear line of sight in 360 degrees.
Step 7. Finally get on to crap bay or dumb tree and buy a second hand household distribution amplifier* for around $30-$40.
Mount the distribution amplifier inside the RV and connect the coax cable to the input side and then hook the TV up to the output side and BINGO you have built and installed a DIY RV TV Antenna to be proud of.
* A distribution amplifier is around the size of a packet of cigarettes and boosts the signal from the wire loops. These come in various sizes from around 10dB to 30dB or more. 10dB will multiply your signal from the loops by 10 times, 20dB will multiply the signal by 100 times and 30 will multiply the signal by 1,000 times. Try to match the size of the distribution amplified to the strength of the signal. That is if you use the antenna in built up areas, you don't need ahuge amplifier/booster - if you will be using the antenna where reception is weak you will need a larger more powerful amplifier/booster. Finally finally if you get fuzzy bands or herringbone patterns your amplifier booster is too strong and is creating feedback internally and needs to be adjusted lower if it has that function or replaced with a smaller unit - same same if the picture pixelises and drops out, so that you need a bigger unit.
I will try to upload several photos and include a link to a Facebook page with a full description. Also check out my DIY project for a UHF CB Double Zepp that I made up from a few bits and pieces for less then $20 that has unique compact size and staggering 3dB over a dipole (4.5dB over an isotrophic) and dominates the channel with clean crisp transmission and reception.
73 from Aaron formerly VK4VOX
P.S. If you see my Toyota Commuter van with a green RV TV Antenna on top lol please don't hesitate to say hi or feel free to message me on Aaron 0416 480 371 (sorry admin and please remove if numbers are not allowed)
-- Edited by Aaron on Friday 20th of August 2021 10:50:19 AM
-- Edited by Aaron on Friday 20th of August 2021 10:54:12 AM
-- Edited by Aaron on Friday 20th of August 2021 10:59:15 AM
-- Edited by Aaron on Friday 20th of August 2021 11:00:38 AM
-- Edited by Aaron on Friday 20th of August 2021 11:06:17 AM
-- Edited by Aaron on Friday 20th of August 2021 11:09:46 AM
-- Edited by Aaron on Friday 20th of August 2021 11:11:08 AM
Step 1. Measure three lengths of soft wire - I used some old power cord - measured and cut to be resonant on three Australian UHF TV frequencies - that is 550Mhz = 54cm, 650Mhz = 46cm, and 750Mhz = 40cm - which will give you three loops to glue inside the bottom frisbee.
Aaron, you may care to reassess the cut frequencies of your three elements. Since you have considered your frequencies the Australian frequencies in the 700 MHz band have been cleared and the spectrum reassigned to mobile data. The bottom channel is CH 28 with a lower frequency of 554 MHz. The top channel is CH 51 with an upper frequency of 698 MHz.
You may also consider adding a filter like this one - 4G/LTE Filter for Digital TV Reception - to eliminate interference from the new mobile data channels.
Aaron said
02:38 PM Aug 21, 2021
Hi PeterD - yep I already considered that - the 750 Mhz element is to give a little bit of extra bandwidth top and bottom of Band IV and V and the interference issue was deliberately left out for the sake of KISS - let them have fun Peter THEN if they have a problem they can always post here for a solution that won't cost the earth - what do you reckon !
PeterD said
04:37 PM Aug 21, 2021
Aaron, forget Band 5, it has been given over to the LTE data services. If you bring your elements closer together in frequency then the reception response acrosss the bane will be a little less lumpy.
Aaron said
10:00 PM Aug 21, 2021
PeterD - maybe you should write an article about antennas instead of posting a critique of my article - did you find anything positive in my post ?
PeterD said
10:16 PM Aug 21, 2021
Yes, that is why I gave a suggestion for you to improve your device.
Aaron said
09:02 AM Aug 22, 2021
How about you find someone else to critique
-- Edited by Aaron on Sunday 22nd of August 2021 12:12:39 PM
Mike Harding said
11:54 AM Aug 22, 2021
Aaron wrote:
How about you find someone else to critique
PeterD has good knowledge in this area, if you listen you may learn....
Aaron said
12:13 PM Aug 22, 2021
I am removing the post to avoid a serial pest
Mike Harding said
12:33 PM Aug 22, 2021
For a working lifetime I have been deeply involved in both electrical engineering and advanced electronic hardware and real-time firmware design. Every time one completes a design it is subject to a design review by peers or people brought in with the specific knowledge required to undertake such a task. It is never pleasant role for the designer, having his lovingly created design which may have occupied him for months, taken apart with forensic precision and then being required to justify every decision he made within the design especially when one cannot justify it or a fault in ones skill or thinking is discovered.
However such a process is essential because it stops people being killed or injured or product recalls which may cost millions - it is not a personal process and should not be seen as such by the designer because *we all* make mistakes and *we all* can learn from others who have good knowledge in areas where we are lacking. The wise man learns from such a process and does not repeat his errors.
Do not take constructive criticism of your efforts personally Aaron and if you feel it's incorrect then ask for clarification or challenge it from a technical viewpoint.
Blues Man said
12:36 PM Aug 22, 2021
Well said Mike Harding.
Aaron said
11:49 AM Aug 23, 2021
well said indeed - likewise I spent over 30 years fault finding in the industry - with electrical engineering background - frequently fixing the mistakes of others (usually industry engineers who were quick with throwing stones but slow when asked for a remedy) - if it were a pissing competition here then who wins ? I did note that nothing was said about the impedance mismatch which gave rise to suspicion of a lot of knowledge about very little - nor was there any mention of front end selectivity in a modern receiver that easily blocks digi coms even while standing under the tx - or the dozen or so grammatical errors - however what was singled out was one loop !!! yet not a mention of what the correct length is that gave rise to the authors bona fides - fortunately the post has been removed to another platform where babies are not thrown out with the bath water and arm chair critics are few and far between - as a first time user it is sadly my last here
-- Edited by Aaron on Monday 23rd of August 2021 03:08:02 PM
Aus-Kiwi said
12:18 PM Aug 23, 2021
Years ago I was putting a you beaut aerial up . I dropped the cable on the floor and the TV worked absolutely brilliant ! The days of old flex cable .
Aus-Kiwi said
12:22 PM Aug 23, 2021
Aaron your right ! To be fair ? This is text and we tend to say one part of things . It often comes through as the cure to things ? Or often misunderstood being text !! We dont want to print out 10 paragraphs to explain what we dont really mean !! Aha
Are We Lost said
12:31 PM Aug 23, 2021
Aaron, I appreciated your write-up. Your design gives an inexpensive yet relatively elegant solution to replace more expensive commercial antennae. I read the comments as suggestions for improvement rather than criticising your design. So I suggest you continue to post such ideas.
Dick0 said
12:45 PM Aug 23, 2021
Aaron wrote:
PeterD - maybe you should write an article about antennas instead of posting a critique of my article - did you find anything positive in my post ?
Aaron, I found your post very informative. Your endeavor to provide a low cost DIY antenna with step by step instructions was admirable and I am sure will be helpful to others.
I would, also, like to see the critics of your project post a detailed DIY solution, as you have, supported with data and explaining the reasons, and provide visual and pictorial and parts source assistance as you have.
I am all for critical opinions and welcome comments but more importantly I would prefer to see the results of the claimed better solutions.
Aaron said
03:12 PM Aug 23, 2021
I was waiting for the author to state how many antennas they had personally built or designed but only heard crickets - its always easier to throw stone - thanks for the comments - I have a killer gorilla folded J-Pole with 3dB or gain for under $10 that I built that I am keen share but reluctant to do so here
Aaron said
03:15 PM Aug 23, 2021
Awesome - your post hit the mark as indeed the one above - thanks for the encouragement, it is MUCH appreciated
Aaron said
03:28 PM Aug 23, 2021
Thanks - the story of a new suit with a soup stain on the tie comes to mind, or is the glass half empty or half full etc - its always easier to pull down then build up - I am still waiting on a answer to my original question - "how many antennas" has the author "designed and or built" ?
I have made it a lifetime endeavor to build simple yet elegant solutions to specific needs - I have published and had peer review all of my designs and received glowing accounts from those who have replicated the design/s - my days go back to correspondence with the legendary Dickie Bird from before him going silent key. I hoped I could one day emulate his efforts. Sadly all I have been capable of were iterations - yet with an eye to improvement so I do get the "critique".
In the scheme of things a single dipole loop in a three loop array being a little shorter (or longer, we know not yet from the author - although I have adjust the calc) would make little if any difference in real life.
What I really was hoping for was questions that would lead to solving other problems . . . I have a UHF CB antenna I built the other day for under $10 with a great band with and almost zero SWR that is ground plane independent and ideally suited to some of the new composite RVs. I am writing it as we speak.
Dick0 said
04:47 PM Aug 23, 2021
Aaron wrote:
Thanks - the story of a new suit with a soup stain on the tie comes to mind, or is the glass half empty or half full etc - its always easier to pull down then build up - I am still waiting on a answer to my original question - "how many antennas" has the author "designed and or built" ?
I have made it a lifetime endeavor to build simple yet elegant solutions to specific needs - I have published and had peer review all of my designs and received glowing accounts from those who have replicated the design/s - my days go back to correspondence with the legendary Dickie Bird from before him going silent key. I hoped I could one day emulate his efforts. Sadly all I have been capable of were iterations - yet with an eye to improvement so I do get the "critique".
In the scheme of things a single dipole loop in a three loop array being a little shorter (or longer, we know not yet from the author - although I have adjust the calc) would make little if any difference in real life.
What I really was hoping for was questions that would lead to solving other problems . . . I have a UHF CB antenna I built the other day for under $10 with a great band with and almost zero SWR that is ground plane independent and ideally suited to some of the new composite RVs. I am writing it as we speak.
Keep at it mate!
Ignore the detractors. Put your ideas forward and let the majority decide if they like your projects.
Lap up the objective opinions and dismiss the subjective ones.
I have a background in Amateur (HAM) Radio and have been thinking about this topic for some time. More recently I found myself standing in the toy aisle of my local Cheap Shop - the one like Ali Baba's Cave full of imports - staring at frisbees wondering. Two frisbees ($4) glued together would make an excellent low drag aerodynamic disc for an RV TV Antenna. Here's what I have come up with in a step by step home brew DIY project that will save your pocket hundreds.
Step 1. Measure three lengths of soft wire - I used some old power cord - measured and cut to be resonant on three Australian UHF TV frequencies - that is 550Mhz = 54cm, 650Mhz = 46cm, and 750Mhz = 40cm - which will give you three loops to glue inside the bottom frisbee.
Step2. Purchase a TV Balun* ($5) from Jaycar or eBay and glue it to the bottom frisbee with the ends near the outside circumference and join the three loops to the Balun.
*A Balun is a matching transformer that matches a balanced loop antenna to unbalance coax cable - balanced to un-balanced, hence the name Balun.
Step 3. Drill a small hole in the center of the bottom frisbee and feed a length of RG6 (or RG59) coax cable through the hole. The cable should be long enough to stretch from wherever you decide to mount the final assembly to the through panel connector or whatever/whichever method you decide to get the coax cable inside the RV. On the frisbee end you will need to connect the coax cable to to the Balun via a F-Type coax cable connector or similar. Again Jaycar and crap bay have these cheap as chips.
Step 4. Build a riser/mount assembly and fit the frisbee to the mount. I suggest you use two PVC floor drain flanges from Bunnings (less then $5 for the pair) and a short length of 50mm PVC plumbers tube for another couple of dollars to join the two flanges. You choose the height by the length of the 50mm tube; I would suggest the entire height be around 15cm. Then glue and bolt the bottom frisbee to the top flange with at least 4 small stainless bolts nuts and washers and snot it up with some Sika or good quality silicone to keep the water out. You decide whether to drill a small hole for the coax cable to feed through the flange mount riser assembly or whatever way you choose to feed the cable from outside.
Step 5. Glue the top frisbee with some super glue or very good quality two pack epoxy and seal the entire circumference with Sika or silicone to keep out the moisture and or rain.
About this time you should have a disc mounted to the two flanges such that it resembles a store bought RV Disc Antenna.
Step 6. Mount the whole assembly to the roof of the RV - this is entirely your decision as to how and where you want to put it. Try to give it clear line of sight in 360 degrees.
Step 7. Finally get on to crap bay or dumb tree and buy a second hand household distribution amplifier* for around $30-$40.
Mount the distribution amplifier inside the RV and connect the coax cable to the input side and then hook the TV up to the output side and BINGO you have built and installed a DIY RV TV Antenna to be proud of.
* A distribution amplifier is around the size of a packet of cigarettes and boosts the signal from the wire loops. These come in various sizes from around 10dB to 30dB or more. 10dB will multiply your signal from the loops by 10 times, 20dB will multiply the signal by 100 times and 30 will multiply the signal by 1,000 times. Try to match the size of the distribution amplified to the strength of the signal. That is if you use the antenna in built up areas, you don't need ahuge amplifier/booster - if you will be using the antenna where reception is weak you will need a larger more powerful amplifier/booster. Finally finally if you get fuzzy bands or herringbone patterns your amplifier booster is too strong and is creating feedback internally and needs to be adjusted lower if it has that function or replaced with a smaller unit - same same if the picture pixelises and drops out, so that you need a bigger unit.
I will try to upload several photos and include a link to a Facebook page with a full description. Also check out my DIY project for a UHF CB Double Zepp that I made up from a few bits and pieces for less then $20 that has unique compact size and staggering 3dB over a dipole (4.5dB over an isotrophic) and dominates the channel with clean crisp transmission and reception.
73 from Aaron formerly VK4VOX
P.S. If you see my Toyota Commuter van with a green RV TV Antenna on top lol please don't hesitate to say hi or feel free to message me on Aaron 0416 480 371 (sorry admin and please remove if numbers are not allowed)
-- Edited by Aaron on Friday 20th of August 2021 10:50:19 AM
-- Edited by Aaron on Friday 20th of August 2021 10:54:12 AM
-- Edited by Aaron on Friday 20th of August 2021 10:59:15 AM
-- Edited by Aaron on Friday 20th of August 2021 11:00:38 AM
-- Edited by Aaron on Friday 20th of August 2021 11:06:17 AM
-- Edited by Aaron on Friday 20th of August 2021 11:09:46 AM
-- Edited by Aaron on Friday 20th of August 2021 11:11:08 AM
Or just a bit of wire behind plastic trim panels.
Aaron, you may care to reassess the cut frequencies of your three elements. Since you have considered your frequencies the Australian frequencies in the 700 MHz band have been cleared and the spectrum reassigned to mobile data. The bottom channel is CH 28 with a lower frequency of 554 MHz. The top channel is CH 51 with an upper frequency of 698 MHz.
You may also consider adding a filter like this one - 4G/LTE Filter for Digital TV Reception - to eliminate interference from the new mobile data channels.
How about you find someone else to critique
-- Edited by Aaron on Sunday 22nd of August 2021 12:12:39 PM
PeterD has good knowledge in this area, if you listen you may learn....
I am removing the post to avoid a serial pest
For a working lifetime I have been deeply involved in both electrical engineering and advanced electronic hardware and real-time firmware design. Every time one completes a design it is subject to a design review by peers or people brought in with the specific knowledge required to undertake such a task. It is never pleasant role for the designer, having his lovingly created design which may have occupied him for months, taken apart with forensic precision and then being required to justify every decision he made within the design especially when one cannot justify it or a fault in ones skill or thinking is discovered.
However such a process is essential because it stops people being killed or injured or product recalls which may cost millions - it is not a personal process and should not be seen as such by the designer because *we all* make mistakes and *we all* can learn from others who have good knowledge in areas where we are lacking. The wise man learns from such a process and does not repeat his errors.
Do not take constructive criticism of your efforts personally Aaron and if you feel it's incorrect then ask for clarification or challenge it from a technical viewpoint.
Well said Mike Harding.
well said indeed - likewise I spent over 30 years fault finding in the industry - with electrical engineering background - frequently fixing the mistakes of others (usually industry engineers who were quick with throwing stones but slow when asked for a remedy) - if it were a pissing competition here then who wins ? I did note that nothing was said about the impedance mismatch which gave rise to suspicion of a lot of knowledge about very little - nor was there any mention of front end selectivity in a modern receiver that easily blocks digi coms even while standing under the tx - or the dozen or so grammatical errors - however what was singled out was one loop !!! yet not a mention of what the correct length is that gave rise to the authors bona fides - fortunately the post has been removed to another platform where babies are not thrown out with the bath water and arm chair critics are few and far between - as a first time user it is sadly my last here
-- Edited by Aaron on Monday 23rd of August 2021 03:08:02 PM
Aaron, I found your post very informative. Your endeavor to provide a low cost DIY antenna with step by step instructions was admirable and I am sure will be helpful to others.
I would, also, like to see the critics of your project post a detailed DIY solution, as you have, supported with data and explaining the reasons, and provide visual and pictorial and parts source assistance as you have.
I am all for critical opinions and welcome comments but more importantly I would prefer to see the results of the claimed better solutions.
I was waiting for the author to state how many antennas they had personally built or designed but only heard crickets - its always easier to throw stone - thanks for the comments - I have a killer gorilla folded J-Pole with 3dB or gain for under $10 that I built that I am keen share but reluctant to do so here
Awesome - your post hit the mark as indeed the one above - thanks for the encouragement, it is MUCH appreciated
Thanks - the story of a new suit with a soup stain on the tie comes to mind, or is the glass half empty or half full etc - its always easier to pull down then build up - I am still waiting on a answer to my original question - "how many antennas" has the author "designed and or built" ?
I have made it a lifetime endeavor to build simple yet elegant solutions to specific needs - I have published and had peer review all of my designs and received glowing accounts from those who have replicated the design/s - my days go back to correspondence with the legendary Dickie Bird from before him going silent key. I hoped I could one day emulate his efforts. Sadly all I have been capable of were iterations - yet with an eye to improvement so I do get the "critique".
In the scheme of things a single dipole loop in a three loop array being a little shorter (or longer, we know not yet from the author - although I have adjust the calc) would make little if any difference in real life.
What I really was hoping for was questions that would lead to solving other problems . . . I have a UHF CB antenna I built the other day for under $10 with a great band with and almost zero SWR that is ground plane independent and ideally suited to some of the new composite RVs. I am writing it as we speak.
Keep at it mate!
Ignore the detractors. Put your ideas forward and let the majority decide if they like your projects.
Lap up the objective opinions and dismiss the subjective ones.