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Author Topic: TS 480 Hetrodyne  (Read 14809 times)
N1DYX
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Posts: 57




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« on: August 04, 2014, 06:58:54 AM »

The computer in my Honda Ridgeline seems to be generating a hetrodyne about every 5kc's on 20 and 17 meters, maybe more bands, I haven't checked yet.  Several people have recommended running a Clear Speech amplified speaker when running mobile for other reasons so I was wondering what the consensus was on that device being easily able to eliminate the hetrodyne I'm hearing.  Would the result be like listening to someone talk underwater and require constant fooling with the speaker adjustment to find the so called "sweet spot" where the carrier is gone?  It isn't extrmely loud but it's loud enough to be very annoying.  If I knew how to do it I'd rather filter out the interference at the source somehow rather than band aid the problem with this speaker so I'm open to any suggestions.

Thank You
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W8JX
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« Reply #1 on: August 04, 2014, 07:48:11 AM »

The computer in my Honda Ridgeline seems to be generating a hetrodyne about every 5kc's on 20 and 17 meters, maybe more bands, I haven't checked yet.  Several people have recommended running a Clear Speech amplified speaker when running mobile for other reasons so I was wondering what the consensus was on that device being easily able to eliminate the hetrodyne I'm hearing.  Would the result be like listening to someone talk underwater and require constant fooling with the speaker adjustment to find the so called "sweet spot" where the carrier is gone?  It isn't extrmely loud but it's loud enough to be very annoying.  If I knew how to do it I'd rather filter out the interference at the source somehow rather than band aid the problem with this speaker so I'm open to any suggestions.

Thank You

Have you simply tried the auto Beat Cancel function built into 480?
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Ham since 1969....  Old School 20wpm REAL Extra Class..
K0BG
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« Reply #2 on: August 04, 2014, 10:59:27 AM »

You're going to have to put up with it.

It really isn't the computer per se, it is the data bus systems. There are three, and the one causing the 5 kHz birdie is the one running at 500kHz. Part of that specific bus is fed back to the top rear portion of the main body (AM/FM antenna location), where most amateur radio antennas are located. The built-in auto-notch should be adequate, and will work better than most external DSP speakers.

There is really no easy way to filter it out, and if you did the bus system wouldn't work as it should. The fuel pump is there too, but chances are you've not noticed unless you operate on 160 meters. The instrument cluster's CPU uses a color burst crystal, so it produces a birdie near 146.16/76. Unless you use that pair, you wouldn't know it is there. There are a few others, but mostly out of band.
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N1DYX
Member

Posts: 57




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« Reply #3 on: August 04, 2014, 07:15:59 PM »

The computer in my Honda Ridgeline seems to be generating a hetrodyne about every 5kc's on 20 and 17 meters, maybe more bands, I haven't checked yet.  Several people have recommended running a Clear Speech amplified speaker when running mobile for other reasons so I was wondering what the consensus was on that device being easily able to eliminate the hetrodyne I'm hearing.  Would the result be like listening to someone talk underwater and require constant fooling with the speaker adjustment to find the so called "sweet spot" where the carrier is gone?  It isn't extrmely loud but it's loud enough to be very annoying.  If I knew how to do it I'd rather filter out the interference at the source somehow rather than band aid the problem with this speaker so I'm open to any suggestions.

Thank You

Have you simply tried the auto Beat Cancel function built into 480?

I didn't know it had that ability, just went out and tried it and it does have an effect on it.  Sort of garbles it vs a steady tone but it definitely does lesson the piercing sound.  I think it garbles the audio a little too but it's had to tell tonight.  I'll experiment a little with it.

Thanks for the education.
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N1DYX
Member

Posts: 57




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« Reply #4 on: August 04, 2014, 07:24:52 PM »

You're going to have to put up with it.

It really isn't the computer per se, it is the data bus systems. There are three, and the one causing the 5 kHz birdie is the one running at 500kHz. Part of that specific bus is fed back to the top rear portion of the main body (AM/FM antenna location), where most amateur radio antennas are located. The built-in auto-notch should be adequate, and will work better than most external DSP speakers.

There is really no easy way to filter it out, and if you did the bus system wouldn't work as it should. The fuel pump is there too, but chances are you've not noticed unless you operate on 160 meters. The instrument cluster's CPU uses a color burst crystal, so it produces a birdie near 146.16/76. Unless you use that pair, you wouldn't know it is there. There are a few others, but mostly out of band.

The notch doesn't touch it much but it's good to know it works as well as the external speaker DSP would, saves me buying one of those.  I do hear the fuel pump but the DSP seems to almost eliminate that.  Ah-h-h the famous color burst crystal again!  I had a 2 meter radio in my other car once, the interference from that thing was so bad the radio was almost useless.  I don't operate 160 and don't plan on it.

Thanks for your reply and info.
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W8JX
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Posts: 13268




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« Reply #5 on: August 05, 2014, 04:27:32 AM »


I didn't know it had that ability, just went out and tried it and it does have an effect on it.  Sort of garbles it vs a steady tone but it definitely does lesson the piercing sound.  I think it garbles the audio a little too but it's had to tell tonight.  I'll experiment a little with it.

Thanks for the education.

It can effect audio because it will remove voice components in same frequency range as current hetrodyne. By trying to position hetrodyne correctly you can minimize its impact on voice.   
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Ham since 1969....  Old School 20wpm REAL Extra Class..
K0BG
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Posts: 10248


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« Reply #6 on: August 13, 2014, 02:52:56 PM »

Bill, you didn't mention the antenna or the location, or if you had chokes applied to the coax and/or control lines?

You have to remember that the three data buses run just about everywhere inside the vehicle. If you have a fair amount of common mode, and it isn't properly choked, then the coax and/or control lines will act like part of the antenna. In fact, it is prudent to apply theses chokes, on every mobile installation. after all, there is always some ground loss present.
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