Traffic Increase

As @abcd567 and others have shown and discussed. There are the electric and mechanical parts to this ‘story’.

Do not/not worry about the impedance mismatch of the cable (electric part). The only concern is the mechanical part, as the plugs, depending on the impedance version, have different dimensions, even though they may appear the same to a quick look.

Again, use any good quality coax, 50 or 75 Ohms does not matter. Use the correct plug for the socket, that is, they must be the same. Both 50 Ohms or both 75 Ohms, no/no mix and match.

There is nothing wrong with using a 75 Ohms plug on 50 Ohms coax or vice-versa. Only the plug, and the socket, must be the same impedance version.

Good quality 75 Ohms coax (RG-6) is plentiful and cheap. This is the cable/satellite TV coax. Not the case with 50 Ohms. Try finding 50 Ohms coax at Walmart.:grin:

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Back on Traffic Increase…It looked like I was going to break my records today, both for planes and positions.

But then what happened? We had a 3 hour long power outage during the best time of the day, on the best day of the week.

There is always next week, I guess. Long live the ‘loose antenna connection’.:rofl:

@abcd567, yup i have a sma to f type connector for that, just clambered up onto roof and mounted the FA antenna, strange though as it currently has less hits than my old spider. Ill look at gain and ppm settings and review it in a few days. I did check both the N to F and the N to sma and the pin in the middle was the same size. Maybe i should loosen up the nut haha.

PPM setting should not be a problem with the generic dongles normally used for ADS-B.

Not a problem for sure, if using an FA dongle, either the Pro or Pro+. Both have a TCXO (Temperature Compensated Crystal Oscillator). If you do, there is a problem with the dongle.

@Dxista i have just added in a Pro+ on both my Dev and Prod boxes - was using a $10 generic dongle before.

Noticed a ten % increase in range and hits using the Pro +, i choose this one as i have two cell towers a Kilometer away, the Pro + dongle surprisingly gave me more noise.

Both setups are a 5 meter length of Quad core RG6 to the Pro + then 5 meters of USB to the PI with spider Antenna (until this morning where i added the FA ant to one setup)

One dongle gets 10% more range than the other, only difference is the type of spider i made, one was a Franklin the other an N type. If the FA antenna doesn’t improve perhaps with a reduction in gain ill just switch back to the N type spider.

Reducing the gain should do it. If I use the piaware default, -10, I receive nothing. If I reduce the gain to 49.6, it starts to work. Right now, the best setting for me is 48.0. Depending on your setup and location, you may need to reduce the gain even more. By adding the Pro+ and the FA antenna, you have 25 dB more gain than before.

Also, do a quick scan of the spectrum. A second, tighter, filter may be an option.

This happened with me also.

At first I thought it is wrong “N-male to F-female” adaptor, may be thin pin 75 ohm version, and ordered 2 more adaptors from 2 different suppliers ensuring there was no mention of 75 ohm in their specs. The other 2 adaptors did not solve the problem.

I then tried gain setting. This also did not solve the problem.

Finally I purchased Flightaware Filter, and bingo! the performance shot up drastically. The reason was very strong Cell/Mobile Phone signals in my area which overloaded the dongle.

The 1/4 wavelength ground-plane antennas (Spider and Cantenna) have hidden advantage of picking much less Cell/Mobile Signals than what is picked by high gain collinear antennas (wire collinear and coaxial collinear). The 1/4wl gp antennas normally work good even without a filter.

I will recommend you run a scan of RF signals to determin their presence and intensity in your area. You can do it very easily with you setup without need to purchase any test equipment or hardware/software:

Do I Need A Filter?

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Quote from Flightaware newsletter June 2018

Thank @abcd567 so even with the Pro + the additional filter will assist? Plus once you added the filter did you still need to set the gain down?

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Yes, in some setups/locations, even Pro Plus needs an external filter.

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Yes, gain setting is necessary even with a filter.

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Ok i have purchased the additional filters, now just the three week wait… in the meantime i think ill revert back to my Spider with the Pro +…

Did you try just lowering the gain? No change? As I said, it could be a case of signal overload, after adding 25 dB of additional gain.

Yup dropped gain to 30 and worked up, stopped at around 40 and now it is similar to the Prod box. I also ran

the filter check as advised by @abcd567 with the following results . Top one is the Prod box with a spider ant and Pro+, the bottom is FA Ant and Pro+

Heaps of noise at the 840 range on both. Interesting to note that the dev box with the FA ANT has less noise at the 940 range but more at the 1090. (both are on a Pro + dongle). Hopefully the additional FA filters on order help both systems.

Very Heath Robinson but is effectively how invention starts.

Geoff

Can we have agreement that in the Flightaware world there are no “F” connectors. If you have an “F” connector it is part of the cable and cable TV world and not the FA filter or FA dongle and as such it needs converting to SMA. (If you want to use cable TV/satellite cable then at least use the correct connectors.)

You need SMA Male connectors to attach to FA Dongles or Filters. (other manufactures may use “F” but not FA)

The “N” connector in the FA Antenna is of the 50 ohm radio type not the 75 ohm Cable TV/satellite type.

There is no RP (reverse polarity) in SMA Cables in the ADS-B world. (RP is computer Wireless stuff)

We all need to be precise in ADS-b talk or the new guys like me get confused. Again. Now, where was I.

Buy a 50 Ohms N male to F female adapter. Followed by F female to an SMA male adapter.:wink:

Buy a 50 Ohms N male to F female adapter. Followed by F female to an SMA male adapter.:wink:

Ahhh, I see you understand.

The N male to F female I bought on ebay had a non-standard thread on the F end.

Fortunately it was cheap enough to toss.

I also bought two N male to SMA male pigtails. Both the N male connectors were terminated incorrectly and held on the end of the cable by the heat-shrink. The braid was not spread under the crimp ferrule.

S.

I know the feeling. I have 4 or 5 of those here. :unamused: Buy the one from Amazon. @abcd567 has the link. I see he is already replying.:wink:

I have been spared this bad situation so far.

I dont understand why there is so strong and unjustified opposition to anything other than 50 ohm / N / SMA

I have been using 75 ohm RG6 with Flightaware antenna and Flightaware Pro Stick for last 3 years without any problem or reduction in performance. All I needed was an N-male to F-female connector at Antenna end and a F-female to SMA-male pigtail at ProStick end.

Image 1 of 4: N-male to F-female Connector

N-male-F-female-375x375px

Image 2 of 4: F-female to SMA-male Pigtail

F-female-SMA-male-Pigtail-350x350px

Image 3 of 4: Dongle End

Image 4 of 4: Antenna End

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