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-   -   Archer Nav performance (https://vansairforce.net/community/showthread.php?t=157050)

Bavafa 01-22-2018 10:17 PM

Does anyone has a good sketch of Bob Archer antenna, I am planning on making one but don?t have a good sketch for the dimensions. Also, what is the grounding requirement for the Archer, in my last plane I had one in the wing tip that was attached to the last rib for good grounding. It worked flawlessly and great reception but I am hoping this time to attach it to the wing tip and only use the nut plates for grounding, I am wondering if that provides adequate ground.

BobTurner 01-23-2018 12:20 AM

You?ll want more than a sketch. The length, width, thickness, and material in the little parallel plate capacitor are fairly critical.
I put my ground leg under the nut plates, fastened with the nut plate rivets. Make sure you have good metal to metal contact all the way from the antenna to the rib.

steve murray 01-23-2018 06:38 AM

Archer Install question
 
I am getting close to installing Archer VOR antenna in RV10 wing tip. The instructions state to run the light wires via the red arrow.



Because I will be mounting the strobe\position lights where the blue circle is, question is, do I need to run the wires along the full length of this front element or can I route the lines halfway up this forward element and turn left (about at the 2nd cable clamp) and go direct to the lights as indicated by the green arrow?

Sam Buchanan 01-23-2018 07:13 AM

Quote:

Originally Posted by Bavafa (Post 1234232)
Does anyone has a good sketch of Bob Archer antenna, I am planning on making one but don?t have a good sketch for the dimensions. Also, what is the grounding requirement for the Archer, in my last plane I had one in the wing tip that was attached to the last rib for good grounding. It worked flawlessly and great reception but I am hoping this time to attach it to the wing tip and only use the nut plates for grounding, I am wondering if that provides adequate ground.

Installation instructions with dimensions:

http://www.aircraftspruce.com/catalog/pdf/SA001A.pdf

Carl Froehlich 01-23-2018 07:16 AM

Quote:

Originally Posted by Bavafa (Post 1234232)
Does anyone has a good sketch of Bob Archer antenna, I am planning on making one but don?t have a good sketch for the dimensions. Also, what is the grounding requirement for the Archer, in my last plane I had one in the wing tip that was attached to the last rib for good grounding. It worked flawlessly and great reception but I am hoping this time to attach it to the wing tip and only use the nut plates for grounding, I am wondering if that provides adequate ground.

Read my post on this thread about how to build your antenna: http://www.vansairforce.com/communit...d.php?t=153969

At any rate - recommend attaching the antenna to the wing rib. This makes wingtip removal much simplier.

Carl

Carl Froehlich 01-23-2018 07:36 AM

Quote:

Originally Posted by steve murray (Post 1234266)
. SNIP

Because I will be mounting the strobe\position lights where the blue circle is, question is, do I need to run the wires along the full length of this front element or can I route the lines halfway up this forward element and turn left (about at the 2nd cable clamp) and go direct to the lights as indicated by the green arrow?

There is no reason to run nav/strobe wires along the antenna as shown in the instruction manual, and some consideration not to. I read these instructions as ?If you really need to have NAV/Stobe wires near the antenna, run them like this?.

I?ve always mounted my homebrew antennas a little aft along the wing rib to provide some separation between the antenna and the nav/strobe/landing light wires. Three RVs flying with this setup (the fourth later this year) with good performace from these antennas.

Carl

Bavafa 01-23-2018 10:24 AM

Quote:

Originally Posted by Carl Froehlich (Post 1234278)
Read my post on this thread about how to build your antenna: http://www.vansairforce.com/communit...d.php?t=153969

At any rate - recommend attaching the antenna to the wing rib. This makes wingtip removal much simplier.

Carl

Hi Carl,
Thanks for the info but could it be that is the wrong thread? I read the discussion about installing a com antenna in the wing tip but did not see anything on building the Bob Archer VOR antenna in that thread.
In regards to attaching it to the wing rib, I think it would be more difficult to remove that way. In my RV7, I had to use a foam to hold it in place since it could not be attached to the wingtip and putting the wingtip on was a bit of work. The way I envision with the antenna attached to the wingtip, I only need to disconnect the coax cable to remove the tip. Any other concern or consideration with this process?

Carl Froehlich 01-23-2018 11:22 AM

Quote:

Originally Posted by Bavafa (Post 1234339)
Hi Carl,
Thanks for the info but could it be that is the wrong thread? I read the discussion about installing a com antenna in the wing tip but did not see anything on building the Bob Archer VOR antenna in that thread.
In regards to attaching it to the wing rib, I think it would be more difficult to remove that way. In my RV7, I had to use a foam to hold it in place since it could not be attached to the wingtip and putting the wingtip on was a bit of work. The way I envision with the antenna attached to the wingtip, I only need to disconnect the coax cable to remove the tip. Any other concern or consideration with this process?

The Archer type comm and VOR antennas are identical except the VOR antenna is slightly longer and mounted horizontal, the Comm antenna is mounted with as much vertical change in the arm that extends out from the wing rib as possible.

If you attach the antenna to a piece of 0.032 angle that is bolted to the wing rib, the wingtip simply slides over the antenna. The antenna never gets moved. The leg of the antenna running off the wing rib just lays inside the wingtip.

Per my previous notes, I point out that you can improve the antenna performace by extending it out into the wingtip as far as you can. The ?tail? gets shorten to maintain the same resonant frequency. This however requires the use of an antenna analyzer to tune it to the appropriate frequency and adjust the gamma match to the 50 ohm feedline. An antenna analyzer should be one of the first shared tools that any EAA chapter to get. The other option is to find an experienced ham radio operator in your area and ask him to help. Most are thrilled to do any antenna work.

Carl

MED 10-04-2018 03:42 PM

Quote:

Originally Posted by Carl Froehlich (Post 1234353)

If you attach the antenna to a piece of 0.032 angle that is bolted to the wing rib, the wingtip simply slides over the antenna. The antenna never gets moved. The leg of the antenna running off the wing rib just lays inside the wingtip.



Carl

Reviving this post looking for advice installing an Archer antenna in a wingtip installed with hinges. The hinge on the wing-side is attached with a piece of the Fiberglas flange between the hinge and the wing skin. My thought is this will insulate the hinge, so I couldn't rely on the hinge to provide the ground connection to the wing. Do you have a photo of the antenna attached to a piece of angle? Do you rivet the antenna to the angle? :confused:

Carl Froehlich 10-04-2018 04:21 PM

Here is a nav antenna I made for a new RV-14A. The overall tail length is long as the photo was taken before it was shorten during the tuning process. The black tape was use to temporarily hold it in place while tuning.
Carl


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