VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #11  
Old 01-09-2019, 05:09 PM
bobg56 bobg56 is offline
 
Join Date: Nov 2018
Location: Peachtree City, GA
Posts: 63
Default

Thanks for the info Steve!
Reply With Quote
  #12  
Old 01-09-2019, 05:32 PM
snopercod's Avatar
snopercod snopercod is offline
 
Join Date: Aug 2016
Location: Asheville, NC
Posts: 1,750
Default

Quote:
Originally Posted by ArlingtonRV View Post
The run from the transponder to the transponder antenna should also be 6.5 feet minimum. The run from the GDL-82 to the transponder is not length limited and can be any length. Any excess cable can just be coiled up and secured wherever it is convenient.
Thanks for the new revision (Rev. 5) of the installation manual. I used Rev. 3 and I see some differences, like the size of the ground plane, for example. You have me confused with the above quote, though. The manual Rev. 5 Section 4.5.1 says "The GDL 82 should be mounted as close as possible to the antenna to reduce the length of coaxial cable between the unit and the antenna." (I used a 24" length of RG-400).
__________________
(2019 dues paid)
Reply With Quote
  #13  
Old 01-09-2019, 05:39 PM
ArlingtonRV ArlingtonRV is offline
 
Join Date: Feb 2005
Location: Marysville, WA
Posts: 466
Default

Quote:
Originally Posted by jdiehl View Post
Would sure like to verify that the RG400 cable must be minimum 6.5í. Iím planning minimum distances between the GDL82 unit and the 1) existing transponder antenna currently between the main gear and 2) the newly installed gps antenna which I anticipate placing on the tip up glare shield. Both of these coax runs will be much less than 6.5í. Is coiling the coax to achieve 6.5í necessary?

Jim Diehl 7A
Lock Haven, Pa
I'm no expert and don't really know what I am talking about, I am merely regurgitating what I have been told. The GDL-82 installation manual page 6-7, Table 6-3 states the minimum and maximum acceptable GPS dB loss. From that, I was working to the 1.5 dB minimum. Page 6-8, third paragraph under 6.4.1 states "For RG-142B or RG-400 coaxial cable, 1.5 dB equates to a length of approximately 6.5 feet of cable with a connector on each end."

That is where the 6.5 feet comes from and, was verified by Christer at Stein Air. Will a shorter cable work? You'd have to ask someone who knows what this all means.

https://m.aircraftspruce.com/catalog...l82install.pdf
__________________
Steve Rush
Arlington, WA
ArlingtonRV on YouTube
RV-8 (Bought Flying)
Glasair Sportsman (Sold)
RV-8 Tail, QB Fuselage (Sold)
RV-4 (Bought Flying) (Sold)
RV-9 Tail
RV-12 120018 Flying (Sold)
RV-7 Tail, Wings, Started Fuse (Sold)
Reply With Quote
  #14  
Old 01-11-2019, 03:52 PM
bobg56 bobg56 is offline
 
Join Date: Nov 2018
Location: Peachtree City, GA
Posts: 63
Default

I spoke to Garmin and was told that the antenna to the GPS needs the 6.5' min. to get that 1.5 loss that's needed. The GDL-82 needs to be close to the Transponder antenna like as what's shown using the C-172 drawing...my question to those who have installed one in an RV did you deviate and put the unit behind the instrument panel? Did you use less than 6.5' of coax to the GPS antenna and lastly did it work?...My Transponder Ant. is just forward of the steps, it looks like the center angular area between the seats is where I may put it so its close to the antenna...I'm still trying figure out the best way, any proven methods will help greatly, thanks to all for the suggestions.
Reply With Quote
  #15  
Old 01-11-2019, 08:03 PM
ALagonia ALagonia is offline
 
Join Date: Jul 2017
Posts: 190
Default

Bought my GDL82 and all,cables from SteinAir. Mounted the GA35 antenna under the cowl. Had SteinAir fabricate the cables. Well worth it. Mounted the GDL82 box behind the panel close to the GTX327 transponder. Easy install and Iím not good at this stuff. Worked without flaw the first time I powered it up. I highly recommend buying everything you need from SteinAir. They know this stuff and can answer all questions.
Reply With Quote
  #16  
Old 01-17-2019, 12:18 PM
bobg56 bobg56 is offline
 
Join Date: Nov 2018
Location: Peachtree City, GA
Posts: 63
Default

How difficult was it programing it with lap top? The instructions tell you to go to Garmin and download the installation tool....I read through it in the install manual, seems a bit confusing.
Reply With Quote
  #17  
Old 01-17-2019, 02:17 PM
ArlingtonRV ArlingtonRV is offline
 
Join Date: Feb 2005
Location: Marysville, WA
Posts: 466
Default

Actually, the most difficult part of the programming, for me, was finding the stupid install tool. I couldn't find it on Garmin's web site so I just Googled it. It can be found here: https://www8.garmin.com/support/down...s.jsp?id=12839.

The second problem I had was my USB cable. For whatever reason the first one didn't work. I got another one and I was able to get the laptop connected. Once connected the actual setup is straight forward. There are a few pieces of information to enter (Tail #, type, existence of ancillary equipment, etc.) and then doing a series of transmit tests to ensure no interference from the comm radio.

Once connected I think the whole thing took maybe 15 minutes.
__________________
Steve Rush
Arlington, WA
ArlingtonRV on YouTube
RV-8 (Bought Flying)
Glasair Sportsman (Sold)
RV-8 Tail, QB Fuselage (Sold)
RV-4 (Bought Flying) (Sold)
RV-9 Tail
RV-12 120018 Flying (Sold)
RV-7 Tail, Wings, Started Fuse (Sold)
Reply With Quote
  #18  
Old 01-18-2019, 04:08 PM
bobg56 bobg56 is offline
 
Join Date: Nov 2018
Location: Peachtree City, GA
Posts: 63
Smile

Thanks for the info, when it comes to software updates and such I cringe because usually its like opening Pandora's Box...I have my software up to 5.6 instead of Vans 5.5...that's because I sent a servo to Dynon for repair and it came back with 5.6, it's a long story but it left scares on me so anytime it comes to a laptop I get nervous, I'm not an idiot I can think but I went down the rabbit hole trying to get everything squared away and it is now, I'm just hoping this ADS-B thing doesn't give me an ulcer...thanks again!
Reply With Quote
  #19  
Old 01-22-2019, 05:38 PM
jdiehl jdiehl is offline
 
Join Date: Jan 2011
Location: Williamsport, Pa
Posts: 166
Default A few final ADSB questions

Alas, I ordered the GDL82 through a local avionics shop. Iíll do the install while theyíll cut the coax cables to size and install the end connectors and help with the data download.
Iím currently using a monopole AV22 transponder antenna that appears incompatible. How about the rami AV74 (not on the garmin list)? Any antenna recommendations that donít rob the bank!?
...and to clarify, 1) the coax to the gps antenna should be 6.5í. 2) the coax from the gdl82 to the L Band transponder should be 6.5í (or less?). 3) keep the coax from the Garmin 327 to the GDL82 a short distance.

Thanks,
Jim Diehl 7A
Reply With Quote
  #20  
Old 01-22-2019, 06:53 PM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 2,857
Default

I have read that a transponder antenna should work fine for 978 MHz.
__________________
Joe Gores
RV-12 Flying
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 01:03 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.