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Magnum S9 question about sensitivity
- Thread starter Supspt454
- Start date
Shadetree Mechanic
Delaware Base Station 808
Does it have a noise blanker? Does it help if you turn the RX gain down a little? I am not familiar with that radio, maybe someone who knows it will stop by.
Chris
Chris
Yes. Noise blanker filters some. It’s not a real strong filter. I have ran the rx down all the way to 50 percent but it starts to have a weak sig.
I don’t know. It has the mosfet finals. I actually had both versions and both had the same issues. I even had a delta force once, and also have a 257hp. All my magnum rigs have been real sensitive and there has to be a way to filter out these noises.
Hmm, may have had a fighting chance with the board I just sent you a pic of.
Now? Not so sure..
The noise can come from many sources, including internal ones.
The problem lies in "overcoming" or "Defeating" that noise at their sources versus just having to run around dealing with it and using the RF gain and Squelch controls. The latter may be your only choice - depending on the chassis you have.
The older Magnums used switches on the front panel and I love those - but were not the best at noise abatement problems - later ones used CPU processor control for turning on and off remotely using toggle functions and special transistors made to work as switches and Audio processing like Noise gating as well as power filtration and RF shunting at the point of contact the switch is supposed to control. Other radio makers like RCI took to this option with some good success - check it out later if you decide to pursue these other avenues of thought and changes...
Yes, changes - not too many people like to know this nor have the ability to do it to their own equipment - but for the most avid and passionate users of radios - they are willing to try just about anything to make their noise floor - more in the basement than say, a tinny air of rushing wind...
IF you turn on your radio and you just have a plain old hiss, this may mean other things that affect the audio chain, not just the receiver is noisy. Although it does lend to know that a noisy noise floor on a receiver that has no antenna connected to it, is a problem child and solutions are not the easiest nor are they for the Feint of heart.
The noise floor of any radio is one of their major selling off or buying one to have it as the best for it - options.
For some radios - it's as simple as changing some resistors in the final audio amp stages that amplify the receivers detected signal some use 2Meg ohm resistors while others use resistors as low at 470 Kilo-ohm - the former value one has a lot more gain, but the latter lower value one offers better bandwidth products to hear your signals as a range of tone versus a mono-tonish compressed result because the dynamic range of the signal is amplified along with the noise embedded in the noise floor and due to it's lack of tone - all scrunches together as one loud "sound" that you are forced to pick out what you really want to hear.
Stopped in to add this...
The above was in a radio the used ST - but it was something they added in to offer the user a better noise floor without having to make a ton of changes to the receiver.
So, before I can even offer a solution - I need to know what I'm up against...
:+> Andy <+:
Now? Not so sure..
The noise can come from many sources, including internal ones.
The problem lies in "overcoming" or "Defeating" that noise at their sources versus just having to run around dealing with it and using the RF gain and Squelch controls. The latter may be your only choice - depending on the chassis you have.
The older Magnums used switches on the front panel and I love those - but were not the best at noise abatement problems - later ones used CPU processor control for turning on and off remotely using toggle functions and special transistors made to work as switches and Audio processing like Noise gating as well as power filtration and RF shunting at the point of contact the switch is supposed to control. Other radio makers like RCI took to this option with some good success - check it out later if you decide to pursue these other avenues of thought and changes...
Yes, changes - not too many people like to know this nor have the ability to do it to their own equipment - but for the most avid and passionate users of radios - they are willing to try just about anything to make their noise floor - more in the basement than say, a tinny air of rushing wind...
IF you turn on your radio and you just have a plain old hiss, this may mean other things that affect the audio chain, not just the receiver is noisy. Although it does lend to know that a noisy noise floor on a receiver that has no antenna connected to it, is a problem child and solutions are not the easiest nor are they for the Feint of heart.
The noise floor of any radio is one of their major selling off or buying one to have it as the best for it - options.
For some radios - it's as simple as changing some resistors in the final audio amp stages that amplify the receivers detected signal some use 2Meg ohm resistors while others use resistors as low at 470 Kilo-ohm - the former value one has a lot more gain, but the latter lower value one offers better bandwidth products to hear your signals as a range of tone versus a mono-tonish compressed result because the dynamic range of the signal is amplified along with the noise embedded in the noise floor and due to it's lack of tone - all scrunches together as one loud "sound" that you are forced to pick out what you really want to hear.
Stopped in to add this...
The above was in a radio the used ST - but it was something they added in to offer the user a better noise floor without having to make a ton of changes to the receiver.
So, before I can even offer a solution - I need to know what I'm up against...
:+> Andy <+:
Last edited:
You mean like a voltage line in filter? It is t coming in through the power cord. It’s coming in through the antenna, but it still has a “hiss” without antenna hooked up. It’s the sensitivity of the radio that is causing it and it’s been on several magnum radios I’ve had. I really like this one so I’m aiming to find a solution. Thanks for the advice.
Yes, that is a good idea, a power supply filter but if he hears other noises from other sources - like even automobiles - then the receive is a little TOO sensitive.
Yes - it helps to determine the noise sources - if the antenna is disconnected and the engine is shut off and yet you hear noise - the radio needs some TLC and a re-tune - or if it's not able to be re-aligned - it may have a blown section of the RF amp or PIN diodes - they could be damaged and there's little protection to keep static and ambient strong signals from entering into and overdiriving the front end amp and IF sections - actually even a poorly tuned IF section from a bad alignment can do this - force the radio into overdrive to receive everything the front end bandpass can allow and then some - you hear rectification of those noise sources because of it.
Or if purchased used - possibly a mod or Receive tune-up may have been done and it's overpeaked.
Remember the previous pic I sent here? Review it, locate L6, it's a coil that is supposed to help pre-select the input from the antenna and is past the PIN attenuation section - this area if not properly tuned can become the source for the excessive noise he hears in his receive.
Any overpeaking usually occurs here - the noise level goes up - I've done it myself and have radios come across my desk tuned this way. Just needs to be retuned.
The open case (canless) design lets' the thing be broadbanded but in itself provides only isolation from the RF Gain bias section used in the PIN Diode attenuation - it simply is a coupling stage to isolate voltages from different stages - Pin and RF amp...
Yes - it helps to determine the noise sources - if the antenna is disconnected and the engine is shut off and yet you hear noise - the radio needs some TLC and a re-tune - or if it's not able to be re-aligned - it may have a blown section of the RF amp or PIN diodes - they could be damaged and there's little protection to keep static and ambient strong signals from entering into and overdiriving the front end amp and IF sections - actually even a poorly tuned IF section from a bad alignment can do this - force the radio into overdrive to receive everything the front end bandpass can allow and then some - you hear rectification of those noise sources because of it.
Or if purchased used - possibly a mod or Receive tune-up may have been done and it's overpeaked.
Remember the previous pic I sent here? Review it, locate L6, it's a coil that is supposed to help pre-select the input from the antenna and is past the PIN attenuation section - this area if not properly tuned can become the source for the excessive noise he hears in his receive.
Any overpeaking usually occurs here - the noise level goes up - I've done it myself and have radios come across my desk tuned this way. Just needs to be retuned.
The open case (canless) design lets' the thing be broadbanded but in itself provides only isolation from the RF Gain bias section used in the PIN Diode attenuation - it simply is a coupling stage to isolate voltages from different stages - Pin and RF amp...
Id try the inline filter and then if that dont help make sure antenna is grounded extremely well as the radio - wire.and for test purposes run a negative jumper wire to the frame/ chassis of the radio,not the covers.seems to me i read a magnum can suffer from not being grounded internally on occasion. Hope we can get you cured.
My delta force had a nasty whine.that filter choked it out n works nice n quiet now
My delta force had a nasty whine.that filter choked it out n works nice n quiet now
- No one is chatting at the moment.