Transponder Ant. was Re: REFLECTOR:anntenas

Scott Derrick reflector@tvbf.org
Fri, 11 Apr 2003 20:21:36 -0600


I like that position!!  Close to the radio, out of the way.

The transponder in in the 2 GHz rangem whats the GPS signal in?

Scott

Alexander Balic wrote:
> I placed my transponder antenna/ground plane under the battery (up front)
> barely fits between the bottom of the battery tray and the fuselage, but
> nothing is in the way of it there, and the coax run is really short I'm not
> quite flying yet, so I can't vouch for the reliability of signal there, but
> it should be good.
> 
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Scott Derrick
> Sent: Friday, April 11, 2003 7:13 AM
> To: reflector@tvbf.org
> 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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