ADS-B DIY Antenna

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trigger said:
This is my scan. My Step is different to yours. Not sure where this gets set.

Your latest filter design looks interesting :cool:
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This scan is exactly what I get when DVB-T is disconnected from noise source and a small length of coax is left connected to the dongle. Seems your dongle is not getting feed from noise source. Are you using right type of MCX connectors? If you use RP-MCX Male instead of regular MCX Male, there will be no connection of central wire. The RP-MCX Male (thread inside) does not have a center pin. The regular MCX Female (thread outside) on the noise generator does not have a pin either. If RP-MCX Male is fitted over regular MCX Female, the center wire will not connect due to missing pin.
 
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ab cd said:
This scan is exactly what I get when DVB-T is disconnected from noise source and a small length of coax is left connected to the dongle. Seems your dongle is not getting feed from noise source. Are you using right type of MCX connectors? If you use RP-MCX Male instead of regular MCX Male, there will be no connection of central wire. The RP-MCX Male (thread inside) does not have a center pin. The regular MCX Female (thread outside) on the noise generator does not have a pin either. If RP-MCX Male is fitted over regular MCX Female, the center wire will not connect due to missing pin.
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Hi ab cd,
I've checked the connectors and I'm sure they are OK. I've stayed away from the RP- type connectors as they are just one more thing to think about.
I'll take another look later today.
 
jepolch said:
Hey Trigger, I did some beekeeping a week ago! I was in Ohio taking care of my sister's house while she was on vacation. I went into her shed to get the "bee suit" and didn't see any pants, so I wore my shorts. I moved very slowly and didn't get stung. Later I talked to my sister who told me "there aren't any pants, we wear blue jeans".
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Hi jepolch,
Very fetching shorts I must say :eek::eek::eek:
There is no way I would handle my bees without a full suit (top and pants). Much too risky.
 
@trigger
Hi Dave
Here are my two scans,
1. With 2m coax, one end of coax connected to DVB-T dongle, other end of coax open.
2. With 2m coax, one end of coax connected to DVB-T dongle, other end of coax connected to Cantenna. No Amplifier . Note high level of Cell/Mobile Phone Signal picked (between 900 & 950 MHz) when Cantenna is connected.

Power Scan Without Source.PNG Power Scan With Cantenna No Amp.PNG
 
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trigger said:
....snip.....
Your latest filter design looks interesting :cool:
Click to expand...
It is very easy to make. Give it a try, nothing to lose. It is to be inserted between Antenna (or noise source) and dvb-t dongle.

It is simply a transmitting antenna (whip 1) connected to source or main antenna, and a receiving antenna (whip2) which catches the signal transmitted by whip1.

Since whip1 is 69mm, it transmits 1090 mhz efficiently, and other frequencies up/down inefficiently, effectively acting as a filter. The whip2 is also 69mm, hence receives 1090 mhz, transmitted by whip1, efficiently and other frequencies up/down less efficiently, acting as a filter. The cascade effect of two whips enhances filtering.

The drink can serves to prevent the radiated energy of whip1 from escaping to space & keeps all inside the can, where it is absorbed by whip2.
 
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Somewhat off topic but perhaps useful information to some. In case anyone of you are constructing collinears, I have recent information that the vinyl outer coating of most coaxes act as an RF shield. Take a sample of the material and place it in the microwave oven with a glass of water next to it to supply a load for the oven, to see if the material warms up, indicating it it absorbs rf.
 
ab cd said:
It is very easy to make. Give it a try, nothing to lose. It is to be inserted between Antenna (or noise source) and dvb-t dongle.

It is simply a transmitting antenna (whip 1) connected to source or main antenna, and a receiving antenna (whip2) which catches the signal transmitted by whip1.

Since whip1 is 69mm, it transmits 1090 mhz efficiently, and other frequencies up/down inefficiently, effectively acting as a filter. The whip2 is also 69mm, hence receives 1090 mhz, transmitted by whip1, efficiently and other frequencies up/down less efficiently, acting as a filter. The cascade effect of two whips enhances filtering.

The drink can serves to prevent the radiated energy of whip1 from escaping to space & keeps all inside the can, where it is absorbed by whip2.
Click to expand...
Very clever! I like it.
 
trigger said:
Hi jepolch,
Very fetching shorts I must say :eek::eek::eek:
There is no way I would handle my bees without a full suit (top and pants). Much too risky.
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Why don't the bees sting him? :confused: :confused: :confused:
May be has he applied some special chemical over his face and body.

bee beard.gif

 
Honey bees aren't very aggressive. That's why they didn't sting me, either. If you move slowly and don't antagonize them, they wont sting. In his case, he probably did get a sting or two, because of the large number of bees. Bee keepers get used to the sting.

PS. I think that guy has a full beard of hair under that beard of bees.

PPS. I'm curious what he put on his face to attract all the bees.
 
He would have the queen in a small cage attached to his chin. The bees will be attracted to the queen pheromone. He probably got a few stings but as jepolch says, honeybees are not aggressive unless you upset them.
 
@trigger
Good News: The Noise Source is no more burning hot. It now remains slightly warm only.
Bad News: The output noise signal is no more there :mad: :mad: :mad:

My deceased Noise Source :(
Noise Source Photo 640 x 460 px.jpg
 
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jepolch said:
Oh that is a shame. Will the seller replace it? Do you have to pay to ship it back to China??
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I have not checked yet, as I found it not working 2 hrs ago. Will have to write to the seller.

Even if seller agrees to replcace, but wants me to send back the defective one, Canada Post charges will be at least $10, half of item's price.
 
ab cd said:
I have not checked yet, as I found it not working 2 hrs ago. Will have to write to the seller.

Even if seller agrees to replcace, but wants me to send back the defective one, Canada Post charges will be at least $10, half of item's price.
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Yeah, that's the bad thing about buying anything from China. I try to only buy things that are very cheap and rugged. Less chance of getting a dud and no way I'll send it back! US Post is ridiculous to send anything to China.
 
@ab cd Sorry to hear your noise source has died. Are there any components that look like they have failed. Run a soldering iron across some of the joints? Have you checked the output from the power supply? The LED won't take much power to light up.
 
trigger said:
@ab cd Sorry to hear your noise source has died. Are there any components that look like they have failed. Run a soldering iron across some of the joints? Have you checked the output from the power supply? The LED won't take much power to light up.
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Thanks for the help tips.
(1) Visual inspection does not reveal any burnt/charred components, nor any open/loose connections/joints.
(2) Measured output of power supply, it is 12 volts.
 
Hey Guys,
Just wanted to let you know, that I'm still alive. It has been very hectic and busy for me past few months. lots of stuff to do for university etc. right now in the middle of packing my bags for my holiday to NW USA ^^. Depending on the wifi I'll be back on the forum more regularly from now on ;).

Also, Just reinstalled my dump1090 decoders (had them removed, because I'm also graphing our PV-panel generation, power usage etc) and installed the original doublelegged spiderantenna inside an old unused plastic chimney/outlet in the roof,, slightly above the roofline. very nice increased reception :D.

spider-roof.png
 
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