Radio question

[bcg]

Yesterday I went to see my dad for lunch and got FF because I always do and I was going into a Bravo. On the way home, everything was great until I switched to Houston Center and then they couldn't hear me on Com 1. I switched to Com 2 and they heard me fine then handed me to their other frequency as I was getting close to home. Thinking maybe it was just the first frequency, I tried Com 1 again and again they couldn't hear me so I used Com 2 the rest of the trip. After landing, I went back to Com 1 and asked for a radio check, which was immediately answered as 5x5 so I don't *think* it's me but, I don't know. Anyone have any idea what could cause this? It was 134.2 and 134.95 with Houston that had the issues.

 

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[EricJ]

3 minutes ago, bcg said:

Yesterday I went to see my dad for lunch and got FF because I always do and I was going into a Bravo. On the way home, everything was great until I switched to Houston Center and then they couldn't hear me on Com 1. I switched to Com 2 and they heard me fine then handed me to their other frequency as I was getting close to home. Thinking maybe it was just the first frequency, I tried Com 1 again and again they couldn't hear me so I used Com 2 the rest of the trip. After landing, I went back to Com 1 and asked for a radio check, which was immediately answered as 5x5 so I don't *think* it's me but, I don't know. Anyone have any idea what could cause this? It was 134.2 and 134.95 with Houston that had the issues.

Do you have one antenna on top and one on the bottom?   Regardless, it was probably just that one of the antennas was shadowed to that particular receiver, but the other one wasn't.   

[bcg]

7 minutes ago, EricJ said:

Do you have one antenna on top and one on the bottom?   Regardless, it was probably just that one of the antennas was shadowed to that particular receiver, but the other one wasn't.   

No, they're both in a line right in front of the windshield in the middle of the avionics cowling so the cable isn't long and they have the same line of sight view.  Com1 is an Icom IC-A200 and Com2 is a Narco MK-12D+.

[ZMERC]

several low altitude sectors in ARTCCs use more than one RCAG site.  Depending on your distance from that site and altitude (lower is worse), you may not be able to transmit to them very well.  I'd try again in the same area at a slightly higher altitude and see if that changes anything.  If not, I guess it's possible your radio may not transmit at the right power at different frequencies, but that's a question for a radio expert (I'm retired ATC, not a radio expert).

I have seen this happen in small areas at certain altitudes at a number of areas in center airspace, the explanations have always been weather anomalies, obstructions, or some other vague reason that may or may not be able to recreated.

Low Altitude sector = at or below flight level 230

ARTCC = Air Route Traffic Control Center (Houston center in your example)

RCAG = Remote Communications Air to Ground site (where the transmitter/receiver the controller is talking from)

RC

retired ATC

[Fly Boomer]

39 minutes ago, ZMERC said:

several low altitude sectors in ARTCCs use more than one RCAG site.  Depending on your distance from that site and altitude (lower is worse), you may not be able to transmit to them very well.  I'd try again in the same area at a slightly higher altitude and see if that changes anything.  If not, I guess it's possible your radio may not transmit at the right power at different frequencies, but that's a question for a radio expert (I'm retired ATC, not a radio expert).

I have seen this happen in small areas at certain altitudes at a number of areas in center airspace, the explanations have always been weather anomalies, obstructions, or some other vague reason that may or may not be able to recreated.

Low Altitude sector = at or below flight level 230

ARTCC = Air Route Traffic Control Center (Houston center in your example)

RCAG = Remote Communications Air to Ground site (where the transmitter/receiver the controller is talking from)

RC

retired ATC

Thanks!  It's nice to get a perspective on these issues we don't always get.

[bcg]

several low altitude sectors in ARTCCs use more than one RCAG site.  Depending on your distance from that site and altitude (lower is worse), you may not be able to transmit to them very well.  I'd try again in the same area at a slightly higher altitude and see if that changes anything.  If not, I guess it's possible your radio may not transmit at the right power at different frequencies, but that's a question for a radio expert (I'm retired ATC, not a radio expert).
I have seen this happen in small areas at certain altitudes at a number of areas in center airspace, the explanations have always been weather anomalies, obstructions, or some other vague reason that may or may not be able to recreated.
Low Altitude sector = at or below flight level 230
ARTCC = Air Route Traffic Control Center (Houston center in your example)
RCAG = Remote Communications Air to Ground site (where the transmitter/receiver the controller is talking from)
RC
retired ATC

I fly through this area often and typically have no issues. In fact, that morning I had gone from ERV to RBD at 5500 and it all worked fine. On the way back, when I had the problems, I was at 8500. We have an RCO for .95 on the field at ERV that we use to get IFR clearances on the ground.

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[EricJ]

9 hours ago, bcg said:

No, they're both in a line right in front of the windshield in the middle of the avionics cowling so the cable isn't long and they have the same line of sight view.  Com1 is an Icom IC-A200 and Com2 is a Narco MK-12D+.

If both of them are there, they're too close together.    One should be moved somewhere else, e.g., on top of the fuselage.

[EricJ]

1 hour ago, ZMERC said:

several low altitude sectors in ARTCCs use more than one RCAG site.  Depending on your distance from that site and altitude (lower is worse), you may not be able to transmit to them very well.  I'd try again in the same area at a slightly higher altitude and see if that changes anything.  If not, I guess it's possible your radio may not transmit at the right power at different frequencies, but that's a question for a radio expert (I'm retired ATC, not a radio expert).

I have seen this happen in small areas at certain altitudes at a number of areas in center airspace, the explanations have always been weather anomalies, obstructions, or some other vague reason that may or may not be able to recreated.

Low Altitude sector = at or below flight level 230

ARTCC = Air Route Traffic Control Center (Houston center in your example)

RCAG = Remote Communications Air to Ground site (where the transmitter/receiver the controller is talking from)

RC

retired ATC

Radio channels are symmetric (aka, reciprocal), though.    If you can hear them, they should be able to hear you except for the differences in transmit power.

[Yetti]

Not knowing your radios....   But guessing they are older.   Your local oscillator from one radio was exciting the other radio.   This happens when frequencies are tuned similar freqs on both radios.

 

[bcg]

Not knowing your radios....   But guessing they are older.   Your local oscillator from one radio was exciting the other radio.   This happens when frequencies are tuned similar freqs on both radios.
 

At the time it started, I had COM2 tuned to the ERV AWOS, 118.125.

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[GMBrown]

I had that happen twice.  As I approached the field after an hour's flight at night, I lost my primary radio (GNS 530).  That gets your attention.  The tower could not hear me, but I could hear them fine.  Switched to secondary radio, an old King that I had refurbished, and landed no problem.  Once on the ground, the tower could hear me fine.  Turns out the 530 didnt have any fan connected to the fan port on the back.  I had the fan hooked up and it hasn't happened again.  My avionics guy thinks the radio got too hot.