best antenna

[trigger]

The CoCo is "love at first sight→ quick matriage→ divorce" "Marry in haste, repent later" as the saying goes.

then after the divorce you realise what the original attraction was and get back together. We should write a book !!

Anyway, I've made some big strides with my CoCo. I now have a 12 segment CoCo (91mm) which gives a range of 200nm with an amplifier. Try Try and Try again. This one is the 12th CoCo I've made.

I've started to feed Flight Radar 24 as T-EGUB1 and here is my first "hit" My first feed.jpg

[abcd567]

then after the divorce you realise what the original attraction was and get back together. We should write a book !!

Anyway, I've made some big strides with my CoCo. I now have a 12 segment CoCo (91mm) which gives a range of 200nm with an amplifier. Try Try and Try again. This one is the 12th CoCo I've made.

I've started to feed Flight Radar 24 as T-EGUB1 and here is my first "hit" [ATTACH=CONFIG]5169[/ATTACH]

CONGRATULATION

This reminds me the song.....
Congratulations
And jubilations
I want the world to know I'm happy as can be.
(Cliff Richard oldies)

[abcd567]

....... Try Try and Try again. This one is the 12th CoCo I've made ........

After my 7th CoCo, and frequent bitter & frustrating experience, I got fed up and practically quit trying it. Your persistance & diligence encourages me to try again

[trigger]

The first successful 8 element CoCo I put to one side as the "standard". I then made another to check the repeatability of construction and it was almost the same regarding range. I then took 4 of the elements from the second one and added to the "standard". It improved the range by a few nm. The 12 element is the one I've installed outside inside some plastic pipe.

I don't really know what has made a successful build. I haven't changed the process.

Take a look at this build for FLARM http://openglidernetwork.wdfiles.com...ar_antenna.pdf I shall try using this build for 1090Mhz.

Do you think I can replace the cone at the base of the antenna with an appropriately cut down can?

[abcd567]

.......Take a look at this build for FLARM..........Do you think I can replace the cone at the base of the antenna with an appropriately cut down can?

Can cut to proper length should work. Most builders use much smaller dia sleeve than a commonly available 330ml/12 oz (66 or 70 mm dia) drink/food can. Better use the smaller diameter ones.

Alternatively use a 3/4" (20mm) dia copper water pipe with end cap. Earlier in this forum, I have posted photos of a cantenna & a sleeve, both made of a narrow drink can & of a 3/4" copper water pipe with end cap.

DSC03299-RR2.JPG.jpeg

[abcd567]

...... I now have a 12 segment CoCo (91mm) which gives a range of 200nm with an amplifier.....

Very good range!

I remember ealier you have mentioned you have a high birch tree which blocks your asdb signals from behind it. Why not you use this birch tree as antenna mast? Mount antenna on top of a fiberglass rod or pvc pipe, and clamp this fiberglass/ pvc pipe to uppermost part of the tree trunk. This way you will overcome the obstruction by the tree, as well as gain antenna height. Many have done this already. See pictures below.

antenna-on-a-tree-1.jpg . antenna-on-a-tree-4.jpg . antenna-on-a-tree-2.jpg . antenna-on-a-tree-5.jpg . antenna-on-a-tree-3.jpg

[gquejada]

(1) Using BNC & F are alternates to each other. Any one is ok. I use F type because in North America, it is used for Cable TV, and its accessories are readily available even in small stores, and are very cheap. Also most of in-Line Amplifiers, power inserters, DC Blockers etc have F-Female Type connectors.

(2) DO NOT use the element length shown in post 1309. It is a FAILED experiment as subsequent trial runs by me and 2 other forum members have proved. The excellent result I got on the very first trial shown in this post was due to extraordinary weather & atmospheric conditions.

Instead, calculate element length by formula "Element Length = Velocity Factor of Coax Cable x 275/2". Check specifications/data sheet of your cable to find Velocity Factor.

If you do not have data sheet/specs, then try these Velocity Factors:

For Coax Cable with Foamed PolyEthylene insulation, also known as FPE insulation, V.F. = 0.83 (use it for RG6 coax as most manufacturers of RG6 coax use FPE insulation). This will give you element length of 114 mm.

For Coax Cable with PolyEthylene insulation, also known as PE insulation, V.F. = 0.66 (use it for RG58 coax most manufacturers of RG58 Coax use PE insulation). This will give you element length of 91 mm.

However the exact value varies from manufacturer to manufacturer & model to model.

Hi, abcd567!

I found the Belden RG Coaxial Reference Guide here - http://www.belden.com/resourcecenter...ad/06-3_15.pdf
But nowhere in the reference does it indicate the exact VF of each cable depending on insulation dielectric used! Where can these values be found?

To add confusion to the "dark arts of coco making" just for RG58, as an example, there are more than 5 different materials used: FEP, FFEP, GIFPE, GIFHDPE aside from the usual PE and FPE you mention above. These diff materials are explained in the reference. I guess we really have to look closely at the specific cable being used. The Reference guide can tell us exactly the dielectric used, but where do we find the exact VF for each different material?

[abcd567]

Hi, abcd567!

I found the Belden RG Coaxial Reference Guide here - http://www.belden.com/resourcecenter...ad/06-3_15.pdf
But nowhere in the reference does it indicate the exact VF of each cable depending on insulation dielectric used! Where can these values be found?

To add confusion to the "dark arts of coco making" just for RG58, as an example, there are more than 5 different materials used: FEP, FFEP, GIFPE, GIFHDPE aside from the usual PE and FPE you mention above. These diff materials are explained in the reference. I guess we really have to look closely at the specific cable being used. The Reference guide can tell us exactly the dielectric used, but where do we find the exact VF for each different material?

Above link gives a document which is only upto page 6.15. These pages are index and give page number of detail specs. For example on page #6.6 RG6U is referred to page # 6.84 which is missing.

Here is the complete catalouge (download & save it on your computer):
http://www.datasheets.pl/coaxial_cab...IAL_CABLES.pdf

Please see below the screenshots 1 & 2 showing how to find exact VF from Belden's Catalog

Belden-1.PNG . Belden-2.PNG

[gquejada]

Above link gives a document which is only upto page 6.15. These pages are index and give page number of detail specs. For example on page #6.6 RG6U is referred to page # 6.84 which is missing.

Here is the complete catalouge (download & save it on your computer):
http://www.datasheets.pl/coaxial_cab...IAL_CABLES.pdf

Please see below the screenshots 1 & 2 showing how to find exact VF from Belden's Catalog

[ATTACH=CONFIG]5178[/ATTACH] . [ATTACH=CONFIG]5179[/ATTACH]

AWESOME!

Thanks again, abcd567!

[SpaxmoidJAm]

when building a coco you really need to solder the connections, just pushing the section together makes for a really variable and poor performing aerial.

When i have tested coco's where the element are just pushed together you only have to think about touching the aerial for it change characteristics.

[abcd567]

when building a coco you really need to solder the connections, just pushing the section together makes for a really variable and poor performing aerial......

A variable coco is a very common experience in push-pin type construction.
I have often thought of it. A possible reason I thought of was that the cut end of core wire is very sharp, and when the core wire is pushed into shield of another element, it damages the shield (foil & braid both, but mainly damages the foil). This damage is hidden under outer jacket of the coax, so never noticed by anybody.

The one successful coco I made was the one in which I rounded the sharp cut ends of the core wire by a file & knife sharpening stone. This rounding should have sure reduced shield damage. However, this is not likely to be the only reason for coco's success, but most likely played some part in it's success.

When i have tested coco's where the element are just pushed together you only have to think about touching the aerial for it change characteristics.

Well if you touch any antenna during testing, it's characteristics will change. If you are listening to an FM station on your FM Radio and touch the tuning circuit, particularly oscillator circuit, you will notice it has detuned.

[SpaxmoidJAm]

i meant when they have been touched to move location etc. they end up being considerably different in their tuning.

I put it down to to the fact that relying on pressure from the cable it self to maintain a good connection is just unreliable, had better success with the push together ones when they were cable tied to a wooden rod.

[wxmeddler]

Hi all,

First post here. Just read through the last 150 pages or so. Wow, what a experiment you all have going here. I got my first SDR USB Dongle a few days ago after pondering for months whether I want to dive into this or not. I'm taking the plunge! I live 2.5 miles from the largest commercial/GA airport in North Dakota (KFAR) and really want to improve the coverage here. Unfortunately, I live in an apartment so I'm somewhat limited in that respect, but I do have a 180° view that includes a clear (minus some trees) to the airport.

I have the SDR dongle hooked up with a 10ft USB 2.0 extension cord to the dongle sitting in the window. So far with the midget antenna I've reached 50NM (80km)with ADS-B and about 80NM (120km) with Mode-S. My Female F to Male MCX is currently in the mail and I went out and purchased 25ft of RG-6 coax today. I was going to cut it up and make a "coco" out of it but after reading the about the dark world of coco's I think I'm going to use it to run to the porch so I don't have to shoot through the glass of the apartment. My plan is to build a cantenna and move on from there.

I have a few questions I didn't see in reading the pages...
1. What's the cutoff for needing/not needing a amplifier on the coax? I have 25 feet to the USB.
2. Does it matter the type of coax/shielding on the 2 whips of the cantenna?
3. Do I need a crimping tool of some sort to make good coax ends or will just those screw on things work?
4. We know the soda can works, has anybody else tried a different size/material (coffee cans?)

Thanks in Advance! Can't wait to get testing!

[YWYY]

Hi I have designed and built successfully an 8 element beam for ADSB. It has the same range as my 9 element wire collinear.
I have built 2 of these both with identical range - 270nm

8element_adsb.JPG


The MMANA files are also attached




Mike
remove the .txt from this file before using in MMANA

[aizaninaleksej]

YWYY:
I wanted to see in the format jpg.
Thank you in advance.