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Errors w/100B

Printed From: Avidyne
Category: Avidyne General
Forum Name: SkyTrax Series ADS-B Receivers & Transceivers
Forum Description: Topics on the Avidyne SkyTrax 978 MHz Receivers & Transceivers
Printed Date: 15 Jul 2024 at 11:54pm
Software Version: Web Wiz Forums 12.01 -

Topic: Errors w/100B
Posted By: gzinga
Subject: Errors w/100B
Date Posted: 28 Mar 2020 at 1:40pm

I flew the new panel for the first time yesterday and I have installed the Avidyne 440 with the Skytrax 100B. I am getting 2 errors: Datalink Data not received and ADS-B sensor traffic has failed. I will have the avionics guy look at it.

Do you have a sense this is easy to fix?

Thank you

Posted By: Ibraham
Date Posted: 28 Mar 2020 at 6:08pm
If the wiring was done correctly, then it is a simple matter of configuration.

Posted By: gzinga
Date Posted: 28 Mar 2020 at 7:43pm
indeed he fixed it today by changing the configuration. at what altitude do you see the ASDB in working at?

Posted By: Ibraham
Date Posted: 30 Mar 2020 at 9:59am
Depends on location of towers in relation to where you are. I believe for traffic should work on the ground.

(see pilot guide page 4-57 Aux Subsystem)
You can go to AUX/SYSTEM/STATUS-Datalink (middle left LSK) to find if you are receiving weather data, and lower left LSK "Datalink/Status"

to check for station, change the lower left LSK to ADS-B/Stations and it will show location and %reception from the towers

Posted By: HenryM
Date Posted: 30 Mar 2020 at 12:47pm
The MLB100 will receive nearby UAT traffic (978 MHz) on the ground. It does not receive 1090MHz traffic, which is the majority of traffic that I see. I wish the MLB100 was dual-band. It requires reception from a tower to be able to show Mode C traffic. 

Weather requires reception from a tower, so whether you receive any on the ground depends on where the nearest tower is. I think the system is designed so you're able to receive ADS-B information from a tower relatively low, something like 1500 ft AGL.

Posted By: gzinga
Date Posted: 31 Mar 2020 at 11:38am
got it. what's the benefit of 978 vs 1090?

Posted By: HenryM
Date Posted: 31 Mar 2020 at 12:24pm
A 978 MHz UAT transponder is only for US use at less than 18,000ft. It is usually cheaper than the 1090 ES transponders. It is not useful outside the US, since most countries require 1090 MHz transponders. Price is the only reason I can see for choosing a UAT transponder. However, the only cheap UAT options for certified planes are the uAvionix products (Skybeacon and Tailbeacon). Even the Stratus ES/ESG transponders are 1090 MHz Extended Squitter transponders. Thus, there aren't very many UAT planes around.

The Avidyne AXP340 is a 1090 MHz ES transponder. This is the ADS-B Out part and gets position information from the IFD navigators. 

The MLB100 is a UAT receiver, the ADS-B In part. It receives ADS-B transmissions from ground towers as well as planes with UAT transponders. Theoretically the ground towers send it data on planes with 1090 MHz ES and Mode C transponders. However, I've seen tower reception occasionally be poor both on the MLB100 and portable units in my plane. In such cases, a dual band receiver would still see the 1090 MHz ADS-B Out units. It is also useful in Mexico, Canada and the Bahamas, where there are no towers, but still quite a few planes with ADS-B Out. You can't rely on it for all traffic, but some is better than none.

The portable receivers are usually dual-band, but they don't display traffic on the panel-mount navigators.

Posted By: gzinga
Date Posted: 31 Mar 2020 at 11:14pm
thank you it sounds like a hit or miss on this one. 

Posted By: HenryM
Date Posted: 31 Mar 2020 at 11:19pm
I am glad I have a 1090 ES transponder for ADS-B Out. I like my AXP340. 

The MLB100 seems to work OK, and I get traffic displayed on Foreflight. I wish it was a dual-band receiver for the occasional lack of tower reception, but it hasn't been a big issue in real life. There's a newer MLB100B but it is still single band. 

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