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Installed New Com Antennas

TomVal

TomVal

Well Known Member
I've had an nagging squeal on my #1 com when transmitting. My existing antennas were of no recognizable brand. This particular antenna did not accept a BNC type connector but required terminal rings for connection.

I replaced both com antennas with RAMI AV-17's. I decided to relocate the aft antenna forward so both antennas sit abreast with appropriate separation. I like the new configuration and no more squeal!:D

I also made access openings and covers in the seat pan area to facilitate future antenna maintenance.

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Wow!! Who built it, and where did they get the avionics? Van's shipped the Rami AV-17 antenna with my avionics kit. Never saw spade connectors on a comm antenna. I must live under a rock.

Glad you found the problem. Your installation looks great, and the extra access panels sounds like a good idea.

Tom
 
todehnal said:
Wow!! Who built it, and where did they get the avionics? Van's shipped the Rami AV-17 antenna with my avionics kit. Never saw spade connectors on a comm antenna. I must live under a rock.

Glad you found the problem. Your installation looks great, and the extra access panels sounds like a good idea.

Tom
Click to expand...

My typo...not spade connectors but terminal ring connectors were used. The aircraft was EAB with a PEX1000 and SL-30 com install. I'll post a photo of the original antennas...very strange...maybe someone will recognize the brand.
 
Comm Radio Squeals

Tom,

A lot of those old antennas and newer radios just don't mix. In simple, if there is a bad SWR between the radio and antenna, it squeals to give you a warning that there is a problem.

I have seen this recently on a Lighting. One radio, with the single antenna located on the belly right between the gear. Adding a 3 foot length of RG400 helped, but moving the antenna back about 3 feet, elimated the problem all together. Also saw a problem with an old Multi-band antenna on an aircraft, so swapped with a new antenna, and problem went away.

Not sure how bad the SWR has to be, but when you get a squeal in the radio, or sidetone, have the SWR checked. Good chance that is the problem. If you have an older one like you did, change it out with a newer one. If it is a newer one, change the location the antenna. A simple test is, remove the antenna from its current location, put an extension on the cable and try it in a different location and see if it still squeals. If it stopped squealing, relocate the antenna. I have a good idea of what type antenna you had, and they don't work and play well with the newer comm radios.

Brian
 
Pdtofly said:
Tom,

A lot of those old antennas and newer radios just don't mix. In simple, if there is a bad SWR between the radio and antenna, it squeals to give you a warning that there is a problem.

I have seen this recently on a Lighting. One radio, with the single antenna located on the belly right between the gear. Adding a 3 foot length of RG400 helped, but moving the antenna back about 3 feet, elimated the problem all together. Also saw a problem with an old Multi-band antenna on an aircraft, so swapped with a new antenna, and problem went away.

Not sure how bad the SWR has to be, but when you get a squeal in the radio, or sidetone, have the SWR checked. Good chance that is the problem. If you have an older one like you did, change it out with a newer one. If it is a newer one, change the location the antenna. A simple test is, remove the antenna from its current location, put an extension on the cable and try it in a different location and see if it still squeals. If it stopped squealing, relocate the antenna. I have a good idea of what type antenna you had, and they don't work and play well with the newer comm radios.

Brian
Click to expand...

Thanks for the input Brian. Installing the newer antennas has solved the problem.

Regards,
 
todehnal said:
Wow!! Who built it, and where did they get the avionics? Van's shipped the Rami AV-17 antenna with my avionics kit. Never saw spade connectors on a comm antenna. I must live under a rock.
.....
Tom
Click to expand...

I bet it was one of these older bent whip types -



Click to see enlarged
 
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