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#11
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I have a friend who installed his transponder aerial in the rear of the stbd gear door on his 27. It was recessed and attached to the inner skin of the door so it didn't protrude much and was well clear of the ground in the event of a wheel up and lifted up out of the way when the gear was down. Quite an elegant solution I thought. I can get pictures to post here next time I'm at the field if anyone is interested :-) Colin |
#12
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ASW27 Trasponder Antenna Installation Inside Fuselage.
On Sunday, February 28, 2016 at 10:11:18 AM UTC-8, wrote:
On Sunday, February 28, 2016 at 11:24:09 AM UTC-5, JS wrote: If it's a "27", not a "27B" or "29", there is a place below the seat pan, under your left knee that a ground plane and stubby antenna can be mounted. It tests fine at TXP certification, is relatively easy to install and connect, and is zero drag. Jim RF transmitting a foot and a half from the family jewels may not be optimum. FWIW UH There's been plenty of tests on that in conjunction with the European personal transponder initiatives. All of my children have had no more that 4 eyes and 3 ears..... |
#13
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ASW27 Trasponder Antenna Installation Inside Fuselage.
At 15:20 28 February 2016, John Cochrane wrote:
You can snake a coax cable back through the fuselage to an L2 antenna in the tail battery box. Not easy or fun but possible. UH solution is "easier" John Cochrane Hello John, many thanks for the information. Was the L2 antenna mounted inside the battery box and doesn't the horizontal stabilizer(carbon-Kevlar- aramid) structure shadow the antenna? Also, did you have to "Fettle" the vertical stab to enable coax routing? Many thanks to all replies. Best regards Paul |
#14
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ASW27 Trasponder Antenna Installation Inside Fuselage.
At 15:20 28 February 2016, John Cochrane wrote:
You can snake a coax cable back through the fuselage to an L2 antenna in the tail battery box. Not easy or fun but possible. UH solution is "easier" John Cochrane Hello John, many thanks for the information. Was the L2 antenna mounted inside the battery box and doesn't the horizontal stabilizer(carbon-Kevlar- aramid) structure shadow the antenna? Also, did you have to "Fettle" the vertical stab to enable coax routing? Many thanks to all replies. Best regards Paul |
#15
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ASW27 Trasponder Antenna Installation Inside Fuselage.
At 15:20 28 February 2016, John Cochrane wrote:
You can snake a coax cable back through the fuselage to an L2 antenna in the tail battery box. Not easy or fun but possible. UH solution is "easier" John Cochrane Hello John, many thanks for the information. Was the L2 antenna mounted inside the battery box and doesn't the horizontal stabilizer(carbon-Kevlar- aramid) structure shadow the antenna? Also, did you have to "Fettle" the vertical stab to enable coax routing? Many thanks to all replies. Best regards Paul |
#16
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ASW27 Trasponder Antenna Installation Inside Fuselage.
I've been looking into ways to secure coax
inside the tailboom. My current avenue of investigation is using magnetic receptive rubber sheet. Wrap a strip of sheet around the coax with appropriate (suggestions welcome) adhesive and use magnet on exterior of tailboom to clamp at appropriate locations well clear of elevator pushrod. Times Microwave has a coax cable and attenuation calculator: http://www.timesmicrowave.com/calculat or/? productId=38&frequency=1090&runLength =26&mode=calculate#form Extra coax length is necessitated by tilt up instrument panel. I'd also like to to put a PowerFLARM dipole in the fin, but that would have to be at least a foot from the xpdr antenna. The battery box is not big enough for both; so may need an opening in the box to achieve enough separation. Once in use for antenna(s), likely the box would no longer be available for ballast. If the front of the nose cone, would work for an L2 antenna, the problem would be much simplified. Any interference with the comm coax and/or antenna would mess things up. |
#17
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ASW27 Trasponder Antenna Installation Inside Fuselage.
On Friday, March 4, 2016 at 8:30:10 PM UTC-5, George Haeh wrote:
I've been looking into ways to secure coax inside the tailboom. My current avenue of investigation is using magnetic receptive rubber sheet. Wrap a strip of sheet around the coax with appropriate (suggestions welcome) adhesive and use magnet on exterior of tailboom to clamp at appropriate locations well clear of elevator pushrod. Times Microwave has a coax cable and attenuation calculator: http://www.timesmicrowave.com/calculat or/? productId=38&frequency=1090&runLength =26&mode=calculate#form Extra coax length is necessitated by tilt up instrument panel. I'd also like to to put a PowerFLARM dipole in the fin, but that would have to be at least a foot from the xpdr antenna. The battery box is not big enough for both; so may need an opening in the box to achieve enough separation. Once in use for antenna(s), likely the box would no longer be available for ballast. If the front of the nose cone, would work for an L2 antenna, the problem would be much simplified. Any interference with the comm coax and/or antenna would mess things up. George, I am afraid the coax cable losses for Flarm antenna would be too high if you run it from the tail of your glider to the instrument panel. Flarm is a very low power unit and the cable length is very important. Also if the horizontal stab is carbon that would not work very well either. |
#18
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ASW27 Trasponder Antenna Installation Inside Fuselage.
LMR-300 would do the job for a price:
COAXIAL CABLE - ATTENUATION POWER HANDLING CALCULATOR Coaxial Cable Data Product: Frequency (MHz): 968 Run Length (Feet): 26 « Reset Calculate » PRODUCT PERFORMANCE PARAMETERS Attenuation: 6.3 db/100ft 20.6 db/100mtr Average Power: 0.35 KW Cable Vg: 85 % Nominal Td: 1.2 nSec/ft 3.92 nSec/mtr Capacitance: 23.9 pF/ft 78.4 pF/mtr Typical Connector Loss: 0.06 dB/pair CABLE ASSEMBLY PERFORMANCE Cable Run Attenuation: 1.6 dB Total Cable Assembly Loss: 1.9 dB Cable Run Efficiency: 68.6 % Cable Run Time Delay: 31.08 nSec As far as RG 58 is concerned, forget it for that length. At 13:13 05 March 2016, Andrzej Kobus wrote: On Friday, March 4, 2016 at 8:30:10 PM UTC-5, George Haeh wrote: I've been looking into ways to secure coax=20 inside the tailboom. My current avenue of=20 investigation is using magnetic receptive=20 rubber sheet.=20 =20 Wrap a strip of sheet around the coax with=20 appropriate (suggestions welcome)=20 adhesive and use magnet on exterior of=20 tailboom to clamp at appropriate locations=20 well clear of elevator pushrod.=20 =20 Times Microwave has a coax cable and=20 attenuation calculator: =20 http://www.timesmicrowave.com/calculat or/? productId=3D38&frequency=3D1090&runL ength =3D26&mode=3Dcalculate#form =20 Extra coax length is necessitated by tilt up=20 instrument panel.=20 =20 I'd also like to to put a PowerFLARM=20 dipole in the fin, but that would have to be=20 at least a foot from the xpdr antenna.=20 =20 The battery box is not big enough for both; =20 so may need an opening in the box to=20 achieve enough separation. Once in use=20 for antenna(s), likely the box would no=20 longer be available for ballast.=20 =20 If the front of the nose cone, would work=20 for an L2 antenna, the problem would be=20 much simplified.=20 =20 Any interference with the comm coax=20 and/or antenna would mess things up. George, I am afraid the coax cable losses for Flarm antenna would be too hi= gh if you run it from the tail of your glider to the instrument panel. Flar= m is a very low power unit and the cable length is very important. Also if = the horizontal stab is carbon that would not work very well either. |
#19
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ASW27 Trasponder Antenna Installation Inside Fuselage.
On Saturday, March 5, 2016 at 11:45:10 AM UTC-5, George Haeh wrote:
LMR-300 would do the job for a price: COAXIAL CABLE - ATTENUATION POWER HANDLING CALCULATOR Coaxial Cable Data Product: Frequency (MHz): 968 Run Length (Feet): 26 Reset Calculate PRODUCT PERFORMANCE PARAMETERS Attenuation: 6.3 db/100ft 20.6 db/100mtr Average Power: 0.35 KW Cable Vg: 85 % Nominal Td: 1.2 nSec/ft 3.92 nSec/mtr Capacitance: 23.9 pF/ft 78.4 pF/mtr Typical Connector Loss: 0.06 dB/pair CABLE ASSEMBLY PERFORMANCE Cable Run Attenuation: 1.6 dB Total Cable Assembly Loss: 1.9 dB Cable Run Efficiency: 68.6 % Cable Run Time Delay: 31.08 nSec As far as RG 58 is concerned, forget it for that length. At 13:13 05 March 2016, Andrzej Kobus wrote: On Friday, March 4, 2016 at 8:30:10 PM UTC-5, George Haeh wrote: I've been looking into ways to secure coax=20 inside the tailboom. My current avenue of=20 investigation is using magnetic receptive=20 rubber sheet.=20 =20 Wrap a strip of sheet around the coax with=20 appropriate (suggestions welcome)=20 adhesive and use magnet on exterior of=20 tailboom to clamp at appropriate locations=20 well clear of elevator pushrod.=20 =20 Times Microwave has a coax cable and=20 attenuation calculator: =20 http://www.timesmicrowave.com/calculat or/? productId=3D38&frequency=3D1090&runL ength =3D26&mode=3Dcalculate#form =20 Extra coax length is necessitated by tilt up=20 instrument panel.=20 =20 I'd also like to to put a PowerFLARM=20 dipole in the fin, but that would have to be=20 at least a foot from the xpdr antenna.=20 =20 The battery box is not big enough for both; =20 so may need an opening in the box to=20 achieve enough separation. Once in use=20 for antenna(s), likely the box would no=20 longer be available for ballast.=20 =20 If the front of the nose cone, would work=20 for an L2 antenna, the problem would be=20 much simplified.=20 =20 Any interference with the comm coax=20 and/or antenna would mess things up. George, I am afraid the coax cable losses for Flarm antenna would be too hi= gh if you run it from the tail of your glider to the instrument panel. Flar= m is a very low power unit and the cable length is very important. Also if = the horizontal stab is carbon that would not work very well either. George, transponder installations usually call for total loss not higher than 2 dB with a practical allowance for a connector of 0.25 dB on each end, leaving 1.5 dB for coax. Your connector allowance is really low. For example Schleicher uses Aircell 7 and total coax length and connectors are just about at max allowance for a Class 1 transponder. I doubt that such loss will be tolerated by PF. I actually discussed this with Schleicher and I was told it will not work in practice. |
#20
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ASW27 Trasponder Antenna Installation Inside Fuselage.
Yes to all that. Trig for example assumes 0.5dB connector losses (thats for the pair of connectors at the RF unit and another pair that joins to the coax to the antenna), but even that may be low vs. what what people will achieve assembling these connectors in practice. And you can get less lossy coax that LMR-300 if you really needed to.
You really don't want the PowerFLARM antenna that close to the Transponder antenna. And I'm not comfortable with a FLARM antenna being close below the RF opaque and reflective horizontal stabilizer. not sure if test flying a mock-up is an option or not but something I'd consider. If you are installing a TRIG transponder mount the RF box somewhere other than the panel, ideally behind the cockpit area, so there is no coax flexing to the panel and the coax is shorter/straighter to the antenna location. For an ASW-27 the old-safe simple external antenna behind the gear doors with a short coax from a nearby TT-22 transponder would be my first (and last) choice. If ordering a new Schleicher from the factory, sure I might go for a tail hinge mounted transponder antenna. I'm not sure why all the complex approach of vertical fin mounted transponder and FLARM antennas is needed in the first place. The transponder antenna behind the gear door works fantastically well, is really not a hassle unless you are stupidly careless.. and then it's easy to replace anyhow). People are getting good performance of FLARM antennas mounted in the cockpit area, including the nose cone area of ASW-27. On Saturday, March 5, 2016 at 10:29:55 AM UTC-8, Andrzej Kobus wrote: On Saturday, March 5, 2016 at 11:45:10 AM UTC-5, George Haeh wrote: LMR-300 would do the job for a price: COAXIAL CABLE - ATTENUATION POWER HANDLING CALCULATOR Coaxial Cable Data Product: Frequency (MHz): 968 Run Length (Feet): 26 Reset Calculate PRODUCT PERFORMANCE PARAMETERS Attenuation: 6.3 db/100ft 20.6 db/100mtr Average Power: 0.35 KW Cable Vg: 85 % Nominal Td: 1.2 nSec/ft 3.92 nSec/mtr Capacitance: 23.9 pF/ft 78.4 pF/mtr Typical Connector Loss: 0.06 dB/pair CABLE ASSEMBLY PERFORMANCE Cable Run Attenuation: 1.6 dB Total Cable Assembly Loss: 1.9 dB Cable Run Efficiency: 68.6 % Cable Run Time Delay: 31.08 nSec As far as RG 58 is concerned, forget it for that length. At 13:13 05 March 2016, Andrzej Kobus wrote: On Friday, March 4, 2016 at 8:30:10 PM UTC-5, George Haeh wrote: I've been looking into ways to secure coax=20 inside the tailboom. My current avenue of=20 investigation is using magnetic receptive=20 rubber sheet.=20 =20 Wrap a strip of sheet around the coax with=20 appropriate (suggestions welcome)=20 adhesive and use magnet on exterior of=20 tailboom to clamp at appropriate locations=20 well clear of elevator pushrod.=20 =20 Times Microwave has a coax cable and=20 attenuation calculator: =20 http://www.timesmicrowave.com/calculat or/? productId=3D38&frequency=3D1090&runL ength =3D26&mode=3Dcalculate#form =20 Extra coax length is necessitated by tilt up=20 instrument panel.=20 =20 I'd also like to to put a PowerFLARM=20 dipole in the fin, but that would have to be=20 at least a foot from the xpdr antenna.=20 =20 The battery box is not big enough for both; =20 so may need an opening in the box to=20 achieve enough separation. Once in use=20 for antenna(s), likely the box would no=20 longer be available for ballast.=20 =20 If the front of the nose cone, would work=20 for an L2 antenna, the problem would be=20 much simplified.=20 =20 Any interference with the comm coax=20 and/or antenna would mess things up. George, I am afraid the coax cable losses for Flarm antenna would be too hi= gh if you run it from the tail of your glider to the instrument panel. Flar= m is a very low power unit and the cable length is very important. Also if = the horizontal stab is carbon that would not work very well either. George, transponder installations usually call for total loss not higher than 2 dB with a practical allowance for a connector of 0.25 dB on each end, leaving 1.5 dB for coax. Your connector allowance is really low. For example Schleicher uses Aircell 7 and total coax length and connectors are just about at max allowance for a Class 1 transponder. I doubt that such loss will be tolerated by PF. I actually discussed this with Schleicher and I was told it will not work in practice. |
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