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pilot623(at)gmail.com Guest
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Posted: Mon Feb 02, 2015 12:35 pm Post subject: NORAD |
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I realized shortly after takeoff from Houston yesterday that radio reception was almost nonexistent and transmission was nonexistent. After dodging controlled airspace at Abilene and Lubbock, I arrived Clovis (KCVN) without issue. Once on the ground, the local FBO said he had received a call from DHS about me but he assured them I was an expected arrival. Besides that, I was squawking 7600 the whole way.
My guess is an antenna problem which would be the easier (cheaper) fix. My com antenna is built into the vertical stab so access there is long gone but I would be able to install an antenna behind the baggage area by clipping the coax and installing a new connector.
My question for the group is what recommendations do you have for com antennas that can install and operate inside the airframe? I'm having the radio bench tested before making my next move. Oh, and I have ordered an I-com handheld which I've wanted to do forever.
Jim
N623JF [quote][b]
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lwheat2083
Joined: 03 Jan 2014 Posts: 33 Location: Moses Lake, Washington
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Posted: Mon Feb 02, 2015 12:54 pm Post subject: NORAD |
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I had to do the same thing on my Pulsar III. If you remove the rudder you can access the two rivets that connect the 1/2 wave dipole glued to the rudder. Just clip the cable and pull out. When you install the antenna don’t forget about the ground plane. You can use aluminum tape or fab on out of thin aluminum. I made mine out of soft aluminum sheet (easier to get the contour) and glued in place. Did a test after installation and SWR was 1.7 to 1 MUCH better than I thought I would get. Any help I can render feel free to contact me. Larry Wheat 206 819-2352 J250 Moses Lake, Washington USA
On Feb 2, 2015, at 12:33 PM, pilot623 <pilot623(at)gmail.com (pilot623(at)gmail.com)> wrote:
[quote] NORAD
I realized shortly after takeoff from Houston yesterday that radio reception was almost nonexistent and transmission was nonexistent. After dodging controlled airspace at Abilene and Lubbock, I arrived Clovis (KCVN) without issue. Once on the ground, the local FBO said he had received a call from DHS about me but he assured them I was an expected arrival. Besides that, I was squawking 7600 the whole way.
My guess is an antenna problem which would be the easier (cheaper) fix. My com antenna is built into the vertical stab so access there is long gone but I would be able to install an antenna behind the baggage area by clipping the coax and installing a new connector.
My question for the group is what recommendations do you have for com antennas that can install and operate inside the airframe? I'm having the radio bench tested before making my next move. Oh, and I have ordered an I-com handheld which I've wanted to do forever.
Jim
N623JF Quote: |
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[b]
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briana(at)xtra.co.nz Guest
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Posted: Mon Feb 02, 2015 2:49 pm Post subject: NORAD |
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Jim,
It is pretty easy to build an equivalent Com antenna inside the fuselage, i.e. a full dipole, with the ferrite toroids on the coax at the centre of the antenna. This avoids the need for a ground plane, and in my view makes an installation which is much easier to adjust if needed.
Originally I made an ELT antenna from copper tape, copying the Bob Nuckolls design that was in Kitplanes many years ago [gee, it was a long time ago now I think back - - about 16 years or so]. The antenna had a dipole centered on 121.5, and also a dipole for 243 on the same centre point. Because of the respective wavelengths these two dipoles function independently, even though they are physically connected at the centre.
The copper tape extends around one side of the fuselage right behind the baggage bulkhead and is glassed over to secure it. The fact that it is in a curve makes virtually no difference to the performance, except that the element lengths might be a fraction shorter. I remember trimming mine with an SWR meter to get the best match at 121.5. It required about 1/2 inch trimming off the ends to get the match exactly ring, with an SWR about 1.2:1 from memory.
I have a photo of the installation I can email to you. Just need to find where it is.
Brian
Quote: | On 3/02/2015, at 9:33 am, pilot623 <pilot623(at)gmail.com (pilot623(at)gmail.com)> wrote:
NORAD I realized shortly after takeoff from Houston yesterday that radio reception was almost nonexistent and transmission was nonexistent. After dodging controlled airspace at Abilene and Lubbock, I arrived Clovis (KCVN) without issue. Once on the ground, the local FBO said he had received a call from DHS about me but he assured them I was an expected arrival. Besides that, I was squawking 7600 the whole way.
My guess is an antenna problem which would be the easier (cheaper) fix. My com antenna is built into the vertical stab so access there is long gone but I would be able to install an antenna behind the baggage area by clipping the coax and installing a new connector.
My question for the group is what recommendations do you have for com antennas that can install and operate inside the airframe? I'm having the radio bench tested before making my next move. Oh, and I have ordered an I-com handheld which I've wanted to do forever.
Jim N623JF
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class="">http://www.matronics.com/Navigator?Pulsar-List
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briana(at)xtra.co.nz Guest
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Posted: Mon Feb 02, 2015 2:53 pm Post subject: NORAD |
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Jim,
Here is the photo of the ELT antenna. Simple.
Brian
[img]cid:2610B933-7476-4675-9A44-7F670FD7B93B(at)Belkin[/img]
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pilot623(at)gmail.com Guest
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Posted: Mon Feb 02, 2015 3:14 pm Post subject: NORAD |
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Looks amazingly like what I have for ELT. Must have been looking at the same plans. Thanks for the picture.
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MyronTruex(at)comcast.net Guest
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Posted: Tue Feb 03, 2015 5:15 am Post subject: NORAD |
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Since you have transmitting and receiving problems it is most likely the antenna. First thing to do is put an ohmeter on the connector to see if it has shorted. If it is not shorted then cut it off a few inches back and install a new one. As suggested a new copper one behind the baggage compartment will work but getting in there is not easy of course. Years ago a friend bought an antenna that was basically the same but was built on a piece of light weight material that allows it to follow the curve of his fuselage.
From: Larry Wheat (lwheat2083(at)gmail.com)
Sent: Monday, February 02, 2015 3:53 PM
To: pulsar-list(at)matronics.com (pulsar-list(at)matronics.com)
Subject: Re: NORAD
I had to do the same thing on my Pulsar III. If you remove the rudder you can access the two rivets that connect the 1/2 wave dipole glued to the rudder. Just clip the cable and pull out. When you install the antenna don’t forget about the ground plane. You can use aluminum tape or fab on out of thin aluminum. I made mine out of soft aluminum sheet (easier to get the contour) and glued in place. Did a test after installation and SWR was 1.7 to 1 MUCH better than I thought I would get. Any help I can render feel free to contact me. Larry Wheat 206 819-2352 J250 Moses Lake, Washington USA
On Feb 2, 2015, at 12:33 PM, pilot623 <pilot623(at)gmail.com (pilot623(at)gmail.com)> wrote:
[quote]
I realized shortly after takeoff from Houston yesterday that radio reception was almost nonexistent and transmission was nonexistent. After dodging controlled airspace at Abilene and Lubbock, I arrived Clovis (KCVN) without issue. Once on the ground, the local FBO said he had received a call from DHS about me but he assured them I was an expected arrival. Besides that, I was squawking 7600 the whole way.
My guess is an antenna problem which would be the easier (cheaper) fix. My com antenna is built into the vertical stab so access there is long gone but I would be able to install an antenna behind the baggage area by clipping the coax and installing a new connector.
My question for the group is what recommendations do you have for com antennas that can install and operate inside the airframe? I'm having the radio bench tested before making my next move. Oh, and I have ordered an I-com handheld which I've wanted to do forever.
Jim
N623JF Quote: |
href="http://www.matronics.com/Navigator?Pulsar-List">http://www.matronics.com/Navigator?Pulsar-List
href="http://forums.matronics.com/">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/contribution
|
href="http://www.matronics.com/Navigator?Pulsar-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
[b]
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ronko11(at)yahoo.com Guest
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Posted: Tue Feb 03, 2015 9:29 am Post subject: NORAD |
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Jim,
One thing to note when taking in all of the antenna options that are being posted is making sure you match your radio's output specifications. My radio and even the Icom radio specifications (and I would expect all Com radios), require a 50 ohm impedance. Some even specify a vertical antenna. Impedance matching to the antenna has allot to do with antenna design. Even if there is some mismatch, the radio will work, but not at its maximum designed output and input performance. Antenna manufacturers when they have a 50 ohm specification, it is just that (by design factors of whip length, material used, diameter size, cable/connector conductor spacing ...).
A dipole antenna can work, but in theory it has an impedance of 73 ohms resistance and 43 ohms reactance. This can be adjusted by the size of wire, changing ideal length of the dipole (in this case shorter than quarter wave and as well as other mechanical elements), but will you know you have a 50 ohm impedance.
Just like getting SWR under 2.0, making sure you have the proper impedance match should be taken into consideration.
Ron
From: pilot623 <pilot623(at)gmail.com>
To: Pulsar-Aviators(at)yahoogroups.com; pulsar-list(at)matronics.com
Sent: Monday, February 2, 2015 2:33 PM
Subject: NORAD
NORAD I realized shortly after takeoff from Houston yesterday that radio reception was almost nonexistent and transmission was nonexistent. After dodging controlled airspace at Abilene and Lubbock, I arrived Clovis (KCVN) without issue. Once on the ground, the local FBO said he had received a call from DHS about me but he assured them I was an expected arrival. Besides that, I was squawking 7600 the whole way.
My guess is an antenna problem which would be the easier (cheaper) fix. My com antenna is built into the vertical stab so access there is long gone but I would be able to install an antenna behind the baggage area by clipping the coax and installing a new connector.
My question for the group is what recommendations do you have for com antennas that can install and operate inside the airframe? I'm having the radio bench tested before making my next move. Oh, and I have ordered an I-com handheld which I've wanted to do forever.
Jim
N623JF
[quote]
[b]
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ronko11(at)yahoo.com Guest
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Posted: Tue Feb 03, 2015 12:41 pm Post subject: NORAD |
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Jim,
One thing to note when taking in all of the antenna options that are being posted is making sure you match your radio's output specifications. My radio and even the Icom radio specifications (and I would expect all Com radios), require a 50 ohm impedance. Some even specify a vertical antenna. Impedance matching to the antenna has allot to do with antenna design. Even if there is some mismatch, the radio will work, but not at its maximum designed output and input performance. Antenna manufacturers when they have a 50 ohm specification, it is just that (by design factors of whip length, material used, diameter size, cable/connector conductor spacing ...).
A dipole antenna can work, but in theory it has an impedance of 73 ohms resistance + 43 ohms reactance. This can be adjusted by the size of wire, changing ideal length of the dipole (in this case shorter than quarter wave and as well as other mechanical elements), but will you know if you have a 50 ohm impedance.
Just like getting SWR under 2.0, making sure you have the proper impedance match should be taken into consideration.
Ron
From: pilot623 <pilot623(at)gmail.com> To: Pulsar-Aviators(at)yahoogroups.com; pulsar-list(at)matronics.com Sent: Monday, February 2, 2015 2:33 PM Subject: NORAD
NORAD I realized shortly after takeoff from Houston yesterday that radio reception was almost nonexistent and transmission was nonexistent. After dodging controlled airspace at Abilene and Lubbock, I arrived Clovis (KCVN) without issue. Once on the ground, the local FBO said he had received a call from DHS about me but he assured them I was an expected arrival. Besides that, I was squawking 7600 the whole way.
My guess is an antenna problem which would be the easier (cheaper) fix. My com antenna is built into the vertical stab so access there is long gone but I would be able to install an antenna behind the baggage area by clipping the coax and installing a new connector.
My question for the group is what recommendations do you have for com antennas that can install and operate inside the airframe? I'm having the radio bench tested before making my next move. Oh, and I have ordered an I-com handheld which I've wanted to do forever.
Jim N623JF
[quote][b]
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