best antenna

[abcd567]

Do any of you know the MDS (Minimum Discernable Signal) for the conventional
ADS-B receiver?
In this case, the MDS would be the smallest signal measured in
microvolts or dBm that would allow the receiver to produce error free data.
Might assist in any Antenna/Pre-Amp additions..etc. Anyone with suitable Test Equipment or the Resources to find this out ?

VE6CPP
F-CYQL1

Hi Jerry. One thing I am sure of is that the DVB-T USB Receiver requires much higher MDS than FR24 supplied receiver. This conclusion is from the tests I conducted on my half-wave dipole as well as on 3-and-half element CoaxialCollinear, with only 11 feet (3.5 meters) RG6 cable between antenna & receiver. I conducted two tests on each antenna, one without amplifier, other with 13-18dB amplifier, all other factors remaining same, and range increased by 150 kms for both antennas. It seems that DVB-T's built-in pre-amplifier has much less gain than the built-in pre-amplifier of FR24 supplied receiver. 73.

[peterhr]

I'm just wondering if its worth splitting this thread into threads for dipoles, whips, Coco's, franklins, etc.

Sent from my Nexus 4 using Tapatalk

[abcd567]

Do any of you know the MDS (Minimum Discernable Signal) for the conventional
ADS-B receiver?..........

VE6CPP
F-CYQL1

The DVB-T USB Receiver Dongle has front-end chip R820T. May be this datasheet can provide some info you want:

http://www.ab9il.net/software-defined-radio/r820T_datasheet.pdf

Right Click the above link and then select "save as" or "save link as" to download pdf document

[mickopla]

I'm curious would there be any lose of range when using the 10 metre cable provided with FR24 equipment to connect antenna to receiver compared with the 5 metre cable?

Mike

[abcd567]

I'm curious would there be any lose of range when using the 10 metre cable provided with FR24 equipment to connect antenna to receiver compared with the 5 metre cable?

Mike

It depends on which cable is supplied by FR24. One of the following 2 is most likely:

For RG58 Cable
At 1000 Mhz, Loss in 10 m (30.5 ft) cable = 17.5dB x 30.5/100 = 5.1 dB
Using 5m will reduce loss by 2.55dB

For LMR400 Cable
At 1000 Mhz, Loss in 10 m (30.5 ft) cable = 4.3dB x 30.5/100 = 1.3 dB
Using 5m will reduce loss by 0.65dB

[mickopla]

It depends on which cable is supplied by FR24. One of the following 2 is most likely:

For RG58 Cable
At 1000 Mhz, Loss in 10 m (30.5 ft) cable = 17.5dB x 30.5/100 = 5.1 dB
Using 5m will reduce loss by 2.55dB

For LMR400 Cable
At 1000 Mhz, Loss in 10 m (30.5 ft) cable = 4.3dB x 30.5/100 = 1.3 dB
Using 5m will reduce loss by 0.65dB

Thanks adcd567 for the info. Receiver is in the loft so will check tomorrow and see which one i have.

Mike

[1090 MHz]

The cable provided with the FR24 is h155 belden.

http://www.kassex.cz/files/default/content/belden/H155A00%20%28PVC%29.pdf

h155 10 m Loss at 1000Mhz is 2.96 dB

LMR-400 10 m Loss at 1000MHz is 1.30 dB


This is why I went with LMR-400

[abcd567]

The cable provided with the FR24 is h155 belden.

http://www.kassex.cz/files/default/content/belden/H155A00%20%28PVC%29.pdf

h155 10 m Loss at 1000Mhz is 2.96 dB

LMR-400 10 m Loss at 1000MHz is 1.30 dB


This is why I went with LMR-400

Your mast is 60 feet (almost 20 meters) high, plus horizontal run of cable say 5 meters, your total cable length from antenna to receiver is about 25 meters.
By using LMR400 instead of H155, you reduced signal loss by 4.2dB**. You took a very wise decision to use LMR400.
**29.6dBx25m/100m - 13dBx25m/100m = 7.4dB - 3.2dB = 4.2dB

[1090 MHz]

Your mast is 60 feet (almost 20 meters) high, plus horizontal run of cable say 5 meters, your total cable length from antenna to receiver is about 25 meters.
By using LMR400 instead of H155, you reduced signal loss by 4.2dB**. You took a very wise decision to use LMR400.
**29.6dBx25m/100m - 13dBx25m/100m = 7.4dB - 3.2dB = 4.2dB

As an experiment I installed a 3dB attenuator at the radio to simulate what it would have been like if I had used the provided H155 cable. At first I didn't notice any difference, but after a while I started to notice I was not seeing as many aircraft on the ground at CYYZ, also my radar lock would drop much more frequently having another station take me over. So having that extra gain really does help you at the end of the day.

[mickopla]

The cable provided with the FR24 is h155 belden.

http://www.kassex.cz/files/default/content/belden/H155A00%20%28PVC%29.pdf

h155 10 m Loss at 1000Mhz is 2.96 dB

LMR-400 10 m Loss at 1000MHz is 1.30 dB


This is why I went with LMR-400

In real world terms distance wise what gain in km's would the LMR 400 have over the h155?

Also to shorten the h155 10m cable provided by FR24 would a crimping tool be required?

[Amper]

Also to shorten the h155 10m cable provided by FR24 would a crimping tool be required?

Don't modify that cable. You agreed that it is still property of FR24.
I asked same question couple a months ago.

[1090 MHz]

Don't modify that cable. You agreed that it is still property of FR24.
I asked same question couple a months ago.

That's why I went with a custom made LMR-400 cable. The FR24 h155 remains unused and untouched.

[abcd567]

That's why I went with a custom made LMR-400 cable. The FR24 h155 remains unused and untouched.

Just out of curiosity, what is the cost of LMR400 for say 25 meters length?

[peterhr]

Just out of curiosity, what is the cost of LMR400 for say 25 meters length?

$60 USD for 100ft

http://www.ebay.com/itm/100-feet-LMR400-Ultra-Low-Loss-Coax-LMR-400-RFC400-/380185962662?pt=LH_DefaultDomain_0&hash=item5884d968a6

[1090 MHz]

I cut my cable to the exact length... and do my own connector installations... it's not that hard with the right tools.