Re[2]: Transponder Ant. was Re: REFLECTOR:anntenas
steve
reflector@tvbf.org
Sat, 12 Apr 2003 20:06:26 +0800
Hi jack,
Saturday, April 12, 2003, 10:44:25 AM, you wrote:
jd> I had my transponder antenna mounted in the outboard strake as the manual
jd> suggested and use to get the same complaints from ATC about intermittent
jd> response. I relocated the antenna to the center of the fuselage near the
jd> gear bulkhead (mounted externally) and have never had a problem with
jd> reception since.
jd> Jack
jd> ----- Original Message -----
jd> From: "Scott Derrick" <scott@tnstaafl.net>
jd> To: <reflector@tvbf.org>
jd> Sent: Friday, April 11, 2003 9:12 AM
jd> 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
>> >
>> >
>>
>>
>> _______________________________________________
>> To change your email address, visit
jd> http://www.tvbf.org/mailman/listinfo/reflector
>>
>> Visit the gallery! tvbf:jamaicangoose
>>
jd> _______________________________________________
jd> To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
jd> Visit the gallery! tvbf:jamaicangoose
Thinking about weak/intermittent transponder replies to the ground radar.....
Anyone know what distance from the ground station is considered normal before ATC expects some
degradation ???
--
Best regards,
steve mailto:steve_beilby@yahoo.com.au