I have a ICOM IC R-75 Reciever and listening to it with a longwire is ok, However ive always had a problem with the white noise from this radio, Because im not an expert on this my question is would the filters they offer quiet this thing down so its quieter? Not even sure if this came with any filtering? Also would there be anyplace i could send it that would install said filters?
ICOM IC-R75
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Ubbe
Member
Try turning down gain and raise the volume. I've tried different antennas, wire, loop, vertical, and they all seem to have the same S/N relation but have different signal strengths. Adjusting gain and volume to make them sound the same shows the exact same relation between noise and signal. If I compare a R75 to msi.sdr and DX394 I can get a more pleasant sound from msi.sdr as the powerful computer makes the noise reductions that are available in the program.
The more narrow filters you select to use the less frequency range ans less noise will the audio have but voice becomes more difficult to understand. It's a fine balance between audio quality and noise level.
You will need to use a balun, perhaps a 9:1, when using a wire or you will pick up a lot of stray noise. I have a 30 meter coax and at the end are a balun that a 22 meter wire are attached to.
/Ubbe
The more narrow filters you select to use the less frequency range ans less noise will the audio have but voice becomes more difficult to understand. It's a fine balance between audio quality and noise level.
You will need to use a balun, perhaps a 9:1, when using a wire or you will pick up a lot of stray noise. I have a 30 meter coax and at the end are a balun that a 22 meter wire are attached to.
/Ubbe
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You might consider an external audio filter. I suspect you are complaining about noise normally present and doubt RF filters are what you want to do. Such filters may be more money than you wish to pay. More modern radios often has such already in them. I have not tried this one and link to it only as an example
Audio DSP Digital Filter SSB CW Ham Radio ADSP Filter Noise Reducer YAESU ICOM | eBay
When the power is turned on to the ADSP, the red LED lights up. After initial power-up, the noise reducer enters bypass mode and the audio signal is directly connected to the noise reducer. When the primary noise reduction is enabled, the yellow LED lights up.
www.ebay.com
There is also this - personally I do not like MFJ stuff and have not tried one:
MFJ-784B Deluxe Tunable DSP Audio Filter | eBay
Find many great new & used options and get the best deals for MFJ-784B Deluxe Tunable DSP Audio Filter at the best online prices at eBay! Free shipping for many products!
www.ebay.com
I guess the best question to ask is,,If you had this Radio , What Antenna etc would you use for it?,,Need tips ?
majoco
Stirrer
The best thing to do is to stop the noise getting in to the radio first rather than trying to eliminate it later. See if you can find the source of the noise first - switch mode power supplies are great noise generator so go around your house and turn off every one you can find. Tune the R75 to the noise without any signal for a reference level on your "S" meter and check the level every time you disconnect anything.
If the noise is external then perhaps a low impedance antenna such as a loop might prove to pickup less noise than your long wire. I changed from a dipole to a loop and my noise is noticeably lower.
You say "from this radio" - have you another radio to compare? A more sensitive radio with no signal and the RF gain full up will produce more noise from the atmosphere - but disconnect the antenna to see what the internally generated noise is like - low noise can mean a better radio but it can also mean lower sensitivity which you don't want!
If the noise is external then perhaps a low impedance antenna such as a loop might prove to pickup less noise than your long wire. I changed from a dipole to a loop and my noise is noticeably lower.
You say "from this radio" - have you another radio to compare? A more sensitive radio with no signal and the RF gain full up will produce more noise from the atmosphere - but disconnect the antenna to see what the internally generated noise is like - low noise can mean a better radio but it can also mean lower sensitivity which you don't want!
If you are not using it already, set the radio to use the RF gain and not the squelch control. This is what Ubbe is referring to. Adjust it to reduce the noise just enough and then back it up to hear what you want. You may need to turn up the volume after adjustment. Read up about it in the R75 manual as well (pages 14 and 30). This simple adjustment has helped many with their radios and the "white noise". Additionally, there is the UT-106 DSP Unit which is made for the Icom R75 and others, you can install into the radio which can also help. I believe they are no longer made, so you'll probably have to find one on eBay and they are probably $100+. Alternative to the UT-106 DSP and the other DSP units noted above there is the Radio Shack DSP. It is external to the radio and typically under $50 used. They may be found on eBay, eham.com, qrz.com and qth.com. You may need to search for a while.
UPDATE: I should note that you may have RFI (Radio Frequency Interference) coming from your own location, or from your neighbors. You may need to hunt down the source if you are causing it. A wire or loop antenna and add on stuff may not eliminate the RFI. There are others sources of RFI as well like AM Broadcast stations, but there are filters for that too.
If I had the R75 I would use a long wire with a 9:1 balun. I would also use a W6LVP active loop with it. The loop can be turned to potentially tune out noise/hash, yet provide you with the signals you want. Some people have noise/hash coming from a specific location and are able to turn and leave the loop set in a particular position. Others need to rotate the loop based on their listening needs, as the loop is directional. I would just use a manual switch two choose each antenna, or you can unplug and switch. If I had to choose just one antenna, I would go with the loop for various reasons you can read up about in the RR Wiki about loop antennas.
UPDATE: I should note that you may have RFI (Radio Frequency Interference) coming from your own location, or from your neighbors. You may need to hunt down the source if you are causing it. A wire or loop antenna and add on stuff may not eliminate the RFI. There are others sources of RFI as well like AM Broadcast stations, but there are filters for that too.
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majoco
Stirrer
See this post....
forums.radioreference.com
...and follow it down where they branch off to talk about the noisy power supply on Icom R7's. Anything that runs off 12VDC in my setup runs off a big linear power supply that I built years ago - no noise from that!
HF receiver Eaton 750
what can folks tell me about this receiver? Been on the hunt for a receiver and about to get a icom 7300 but saw a post that has my attention on this receiver. I tried to look up the external antenna connection but can't find much about it. How good is this radio? Thanks.
...and follow it down where they branch off to talk about the noisy power supply on Icom R7's. Anything that runs off 12VDC in my setup runs off a big linear power supply that I built years ago - no noise from that!
w2xq
Mentor
Before you try the myriad of antenna suggestions above, have you disconnected the antenna and see if you still have the white noise? If yes, then you will have to investigate why. Good luck.
I disconnected the Antenna and the it is alot better,,What should i do as far as resolving this?
I owned a few R75's over the years, they were all noisy. ICOM's NB and NR are pretty much useless. HF/SW/MW receivers are always pretty noisy when compared to full-quieting FM & Digital like you might be used to when you use a scanner. The ICOM IC-R75 is very good. You can spend thousands on a receiver that may not sound much better. You can spend a lot more on accessories, antennas, filters, noise cancellers, special speakers, ETC and you still won't be impressed. It's the nature of those bands and the technology.
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Ubbe
Member
If you do not have the space then use a loop. I have a Wellbrook ALA loop that costs something like $300 that receive pretty much exactly the same as a 50 cent electrical wire at my place. Also the $100 DX394 sometimes receives better than the $500 R75. Reception are extremely dependent of the time of day, the weather and other things that change conditions much more than antenna types and quality of receiver.
I would suggest trying a cheap loop, like the MLA-30+
With all the interferencies in the neighbourhood I've pretty much given up and use the online kiwisdr net that hears much better than what I can accomplish. kiwisdr.com/public/
/Ubbe
I would suggest trying a cheap loop, like the MLA-30+
With all the interferencies in the neighbourhood I've pretty much given up and use the online kiwisdr net that hears much better than what I can accomplish. kiwisdr.com/public/
/Ubbe
I just got a used R75 in prestine condition. Someone posted listening to HF with a discone so tried it and compared it to my long wire. The discone did just as good and sometimes better than the wire. As was posted, the noise is dependent of conditions of the night. Some nights its noisy, other nights its not to bad. But if you have constant noise throughout your bands, you have something close generating it and you need to find the source.
w2xq
Mentor
Perhaps try a different external power supply, preferably a non-switching one, to see if the noise disappears. (I use an Astron RS-20 for my toys.) Perhaps a local radio amateur/club can help you by powering your radio to test it. If the receiver is still noisy or you have no alternative way of diagnosing the receiver, you may have to inquire of ICOM. It is difficult to remotely diagnose possible ills of an old receiver. Sorry.
I use an inverted l antenna into a 1:1 current balun and then fed with rg6 and it works great. Noted that I use a loading coil at the top of the L and that is close wrapped with about 250 feet of 14awg wire on a 3 inch diameter piece of pvc. It's only up 25 feet but works excellent on my r75. Has less noise then my icom 706 using a butternut vertical. The antenna is resonant around 1.8 mhz so it is super on mw, ndb, and can pick up wwvb.
And I'm using the icom power supply that came with it
And I'm using the icom power supply that came with it
THANK YOU
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