Transponder Ant. was Re: REFLECTOR:anntenas

Rodney Brim reflector@tvbf.org
Fri, 11 Apr 2003 09:48:25 -0700


Alexander,
I found that building a flat anntena plane, underneath the battery wasn't
effective about 10% of the time.  Since having Center not suddenly see you
in the soup in a busy area, even once, is an experience you don't want to
repeat, I added a shark fin (underneath the flat plane which was still
glassed in to the inside of the cowl below the battery).  I haven't had any
disconnects with Center since.

Rodney Brim,


-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Alexander Balic
Sent: Friday, April 11, 2003 7:43 AM
To: reflector@tvbf.org
Subject: RE: Transponder Ant. was Re: REFLECTOR:anntenas


mine is 6" dia,with two small flats on it to fit under the battery tray

-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Scott Derrick
Sent: Friday, April 11, 2003 7:38 AM
To: reflector@tvbf.org
Subject: Re: Transponder Ant. was Re: REFLECTOR:anntenas


Really that big?

I think the one in the strake is 3x3

Scott

Fred Marconi wrote:
> 9" X 9" WOULD DO NICELY.
>
> FRED
> ----- Original Message -----
> From: "Scott Derrick" <scott@tnstaafl.net>
> To: <reflector@tvbf.org>
> Sent: Friday, April 11, 2003 9:12 AM
> Subject: Transponder Ant. was Re: REFLECTOR:anntenas
>
>
>
>>I'll second Wayne's "DO NOT" for the transponder. Mine is in the strake
>>in the outside wing bolt hole space.  I get periodic complaints from ATC
>>about intermittent transponder.  I think I'll purchase another antenna
>>and try mounting one closer to the transmitter.
>>
>>I don't want it out side though, don't have any external antennas now,
>>and don't want any.
>>
>>Where's a good spot in a standard RG?  I was thinking about mounting it
>>to the bottom of the rear seat?
>>
>>How big does the ground plane need to be?
>>
>>My GPS antenna is mounted to the inside of the nose access door, 4 feet
>>of cable and works great.
>>
>>Scott
>>
>>Wayne Lanza wrote:
>>
>>>
>>>Regarding the antennas, our experience at the builders center points to
>>>the following:
>>> > Transponder ANT = between the firewall and gear bulk head, on center
>>>line. DO NOT
>>>put this ANT out in the strake, many transponders don't like to drive
>>>this much wire!
>>> > GPS = on top of the landing light or on top of the canard, keep this
>>>wire under 8' long.
>>> > Marker Beacon = Inside or outside of the keel, or on the floor near
>>>the keel. Locate
>>>the foil such that you don't tear it up when upholstering or mounting
>>>the seats...
>>> > Glide Slope = On the floor under the copilot front seat area.
>>> > AM/FM = Not too critical, string a 23" piece of the ANT wire (center
>>>conductor only)
>>>across the under side of the structure in front of the canopy. Make sure
>>>that the pitch
>>>trim spring doesn't interfere.
>>> > ELT = Mount the ELT to the floor between the gear bulk head and the
>>>keel bulk head
>>>on the copilot side. Run two 23" foils on a diagonal centered at the
>>>fuselage joint, the
>>>angle of the foils is such that they are fairly straight (they might
>>>wrap onto the ceiling).
>>>This is not super critical, but this antenna should be vertically
>>>mounted not horizontal!
>>>Use the torroids and connect the coax braid to the lower foil. Secure
>>>foils, torroids and
>>>the end of the lead in coax with 1 ply of bid. This needs to be
>>>shock/impact secured.
>>> > ADF = I've heard of them :-)
>>>
>>>In general, use the correct type of coax (not TV wire or solid center
>>>conductor), use the
>>>proper BNC terminals and appropriate tools. Keep the coax runs short and
>>>secure.
>>>
>>>Fly Safe,
>>>Wayne Lanza
>>>Composite Design, Inc.
>>>(electrical weenie at the Velocity Builder's Center)
>>>____________________________________________________________________
>>>On Friday, April 11, 2003, at 06:37 AM, Lynn Gallup wrote:
>>>
>>>    Noel,
>>>    As near as possible, I followed the suggestions in the Velocity
>>>    manual. After 185 hours flying my airplane in a wide variety of
>>>    circumstances I can pronounce perfect operation of my nav & com
>>>    radios, localizer & glideslope, marker beacon receiver and
>>>    transponder. Even the ADF works acceptably although its range is a
>>>    little short. The GPS would benefit from shielding or a slight
>>>    relocation as it will blank out if one of the nav receivers is tuned
>>>    to a particular VOR frequency. (Leakage of nav's IF frequency signal
>>>    out of the localizer antenna overcomes the satellite signals.)
>>>
>>>    Mine is a hatch door, long wing, RG. The antenna locations are:
>>>
>>>    Com antennas - In the tip sails.
>>>    Nav antenna - One shared antenna on top of fuselage about four
>>>    inches forward of engine bulkhead.
>>>    Marker beacon antenna - Along right side about two inches below
>>>    windows.
>>>    Transponder antenna - Bottom of fuselage below right rear seat.
>>>    ADF antennna - Bottom of fuselage below left rear seat.
>>>    Localizer antenna - On canard top surface, center-line of fuselage.
>>>    GPS antenna - Front of canard top, centered. Forward of localizer
>>>    antenna. It should be remounted under the top of the fuselage above
>>>    the localizer antenna.
>>>
>>>    Regards,
>>>    Lynn
>>>    =====================
>>>    At 11:46 PM 4/10/2003 Thursday, you wrote:
>>>
>>>
>>>    Now that it's finally starting to warm up, I'm doing the planning
>>>    for my summer project... The wings / canard.
>>>    I realize that antenna placement is variable, But...
>>>    What do I really need? Do I need a Com and Nav in each wing?
>>>    Where's the best place for a glideslope antenna. The keel was
>>>    already down when I got the kit.
>>>    I assume the transponder would be best on the floor, and the gps on
>>>    the ceiling.
>>>    What about something for the am/fm?
>>>    I've seen Don's elt antenna on the main wingspar shearweb, and it
>>>    looked pretty survivable.
>>>
>>>    What's popular / what's practical
>>>
>>>    Noel 3suv103
>>>
>>>
>>
>>
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