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#1
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Hi,
I am beginner .. sorry if some of this seems like stupid question(s): I have installed a ICom F2010(2020) into my Jeep. The radio unit itself is installed in the back where the CD changer was, the antenna cable is a bit too long, so it is stored in a loop. Control unit is seperated with 8 meter cable from main unit and is mounted underneath the ashtray (so basically it is sitting above the gear box). The antenna is mounted on the roof the car: A GME 409L (ground independend), mounted on a spring S004 Frequencies used are in the 460Mhz-490Mhz range. The problems I am experiencing now: - Whenever the unit is Rx ... I can hear a whisling sound, which is only audible if I accelerate (there seems to be a relationship to the RPMs ?) - If the car is stationary I can Rx ok, once the car is moving (maybe 50 kmh) the Rx is braking up Is above normal, if not .. any ideas how to fix it ? I am aware that I should shorten the antenna cable, rather than looping it. Could the transmition be causing the whisling noises ? Is the antenna I am using a piece of s(*^&(^ and should I use a different one ? Thanks, D. |
#2
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#3
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In article ,
Howard wrote: Sounds a lot like 'alternator whine'. Is your radio hooked directly to the battery, if not then proceed to make it so (and fuse both positive and negative leads). If that does nothing, or not enough, to fix the problem you may wish to consider a DC noise filter. RatShack carries a couple of them, the 10 amp model is about $16 (pn 270-051). Even if the radio only draws 10 amps on transmit, I'de get the 20 amp filter. You'll have less voltage loss that way. -- Larry Weil Lake Wobegone, NH |
#4
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In article ,
Howard wrote: Sounds a lot like 'alternator whine'. Is your radio hooked directly to the battery, if not then proceed to make it so (and fuse both positive and negative leads). If that does nothing, or not enough, to fix the problem you may wish to consider a DC noise filter. RatShack carries a couple of them, the 10 amp model is about $16 (pn 270-051). Even if the radio only draws 10 amps on transmit, I'de get the 20 amp filter. You'll have less voltage loss that way. -- Larry Weil Lake Wobegone, NH |
#6
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Dr.,
thanks ... alternator whine ... makes sense ... I split of the + from an accessory outlet in the boot (yes .. the cables are rated with enough AMPs), which comes from the fuse box ... picked up a noise filter today .. will put it in tomorrow ... sure it will work grounding .. just double checked everything .. seems to be ok .. I think the only way to achieve a better grounding would be to put a cable directly to the engine block, rather through the frame ;-) regards the 'breaking' .. it only happens with certain TXs, not all do the 'breaking-thingy' (hope that is the correct technical term) professional assistance .. nah .. don't think so .. this is a hobby .. so I shall learn and learn and learn until I know and can do it myself spell-checking .. if you can get me the partnumber I order a spell-checker with ICom .. called them today to order one.. they asked me to spell spellchecker .. but I didn't have a spell-checker-speller .. so .. need your assistance here .. thx Thanks, D. "Dr. Anton T. Squeegee" wrote in message ... In article , says... Hi, I am beginner .. sorry if some of this seems like stupid question(s): The only "stupid" question is the one you never ask. Frequencies used are in the 460Mhz-490Mhz range. Since the 2010/2020 series are FCC Part 90 type accepted, this is a good match. The problems I am experiencing now: - Whenever the unit is Rx ... I can hear a whisling sound, which is only audible if I accelerate (there seems to be a relationship to the RPMs ?) Alternator whine. Very common. You need to check that all your radio and antenna ground connections are clean and solid, that the body of the car is well-bonded (electrically speaking) to the engine block, and hence to the negative battery termimal, AND you should purchase and install an alternator whine filter. - If the car is stationary I can Rx ok, once the car is moving (maybe 50 kmh) the Rx is braking up That's "breaking," BTW. Possible antenna problems. You should check the forward and reflected power with a good-quality thruline RF wattmeter, such as a Bird 43 series or a Telewave. Also, the antenna's outer shell conductor may not be well grounded to the frame of the vehicle. If any or all of the above sounds unfamiliar or overly complex, I would strongly recommend that you seek professional assistance from whatever amateur radio club or two-way radio shop is local to your area. You cannot properly troubleshoot things like antenna problems without the proper test equipment. Is above normal, if not .. any ideas how to fix it ? I am aware that I should shorten the antenna cable, rather than looping it. Antenna cables should be cut to length unless the manufacturer of the antenna explicitly states otherwise in their printed instructions (which should have been included with the antenna). Could the transmition be causing the whisling noises ? No. That's "transmission," BTW. Is the antenna I am using a piece of s(*^&(^ and should I use a different one ? No idea. Antennas are pretty simple devices. If the one you have is built for the frequency range you're using, I don't see why it would not work if it was properly installed. -- Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute. (Known to some as Bruce Lane, ARS KC7GR, kyrrin (a/t) bluefeathertech[d=o=t]calm -- www.bluefeathertech.com "If Salvador Dali had owned a computer, would it have been equipped with surreal ports?" |
#7
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Dr.,
thanks ... alternator whine ... makes sense ... I split of the + from an accessory outlet in the boot (yes .. the cables are rated with enough AMPs), which comes from the fuse box ... picked up a noise filter today .. will put it in tomorrow ... sure it will work grounding .. just double checked everything .. seems to be ok .. I think the only way to achieve a better grounding would be to put a cable directly to the engine block, rather through the frame ;-) regards the 'breaking' .. it only happens with certain TXs, not all do the 'breaking-thingy' (hope that is the correct technical term) professional assistance .. nah .. don't think so .. this is a hobby .. so I shall learn and learn and learn until I know and can do it myself spell-checking .. if you can get me the partnumber I order a spell-checker with ICom .. called them today to order one.. they asked me to spell spellchecker .. but I didn't have a spell-checker-speller .. so .. need your assistance here .. thx Thanks, D. "Dr. Anton T. Squeegee" wrote in message ... In article , says... Hi, I am beginner .. sorry if some of this seems like stupid question(s): The only "stupid" question is the one you never ask. Frequencies used are in the 460Mhz-490Mhz range. Since the 2010/2020 series are FCC Part 90 type accepted, this is a good match. The problems I am experiencing now: - Whenever the unit is Rx ... I can hear a whisling sound, which is only audible if I accelerate (there seems to be a relationship to the RPMs ?) Alternator whine. Very common. You need to check that all your radio and antenna ground connections are clean and solid, that the body of the car is well-bonded (electrically speaking) to the engine block, and hence to the negative battery termimal, AND you should purchase and install an alternator whine filter. - If the car is stationary I can Rx ok, once the car is moving (maybe 50 kmh) the Rx is braking up That's "breaking," BTW. Possible antenna problems. You should check the forward and reflected power with a good-quality thruline RF wattmeter, such as a Bird 43 series or a Telewave. Also, the antenna's outer shell conductor may not be well grounded to the frame of the vehicle. If any or all of the above sounds unfamiliar or overly complex, I would strongly recommend that you seek professional assistance from whatever amateur radio club or two-way radio shop is local to your area. You cannot properly troubleshoot things like antenna problems without the proper test equipment. Is above normal, if not .. any ideas how to fix it ? I am aware that I should shorten the antenna cable, rather than looping it. Antenna cables should be cut to length unless the manufacturer of the antenna explicitly states otherwise in their printed instructions (which should have been included with the antenna). Could the transmition be causing the whisling noises ? No. That's "transmission," BTW. Is the antenna I am using a piece of s(*^&(^ and should I use a different one ? No idea. Antennas are pretty simple devices. If the one you have is built for the frequency range you're using, I don't see why it would not work if it was properly installed. -- Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute. (Known to some as Bruce Lane, ARS KC7GR, kyrrin (a/t) bluefeathertech[d=o=t]calm -- www.bluefeathertech.com "If Salvador Dali had owned a computer, would it have been equipped with surreal ports?" |
#8
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The radio unit itself is installed in the back where the CD changer
was, the antenna cable is a bit too long, so it is stored in a loop. Control unit is seperated with 8 meter cable from main unit and is mounted underneath the ashtray D- My guess is that the whistle is alternator whine, as others have suggested. If so, it is probably not coming in through the antenna, but through the power connection to the audio amplifier. I would suggest using a pair of 10 AWG wires directly from the battery terminals to the main unit (Fused, of course). Either alternator or ignition noise might be coupled through the control unit's ground, so try isolating it. Let it obtain audio, power and ground through the 8 meter cable. If the antenna is ground independent, make sure you didn't ground it by accident. There could be noise conducted through its shield back to the radio. 73, Fred, K4DII |
#9
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