Pro-404 Signal issues

BC2001

Jesse
Joined
Oct 10, 2015
Messages
252
Location
Pineville, KY
Does anyone know what could be causing an analog Pro-404 to not recieve as good as good as it once was?
So, for the last several months, I have noticed it has lost a good deal of sensitivity. For example, I used to be able to receive better on the Airband, and VHF Public safety; but now, it is weaker of a signal. Also, this could be related, when I take the antenna completely off and nothing it attached, I do not hear clear, loud static as I did before; instead, I hear some sort of lower volumed static. It's almost as if it is trying to receive a weak signal, but there is no antenna attached.

Is there any obvious reason for this? And if so, is there an easy fix? It may be a cheap priced scanner, but I would like to get this one working again.
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Edit: I would also like to add that when I hear a transmission on airband, the audio is low, and even if isn't on my other scanners.
 
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tvengr

Well Known Member
Joined
Feb 10, 2019
Messages
9,401
Location
Baltimore County, MD
That could be due to an antenna problem or the attenuator is turned on if the scanner has one. The volume of FM signals is independent of signal strength. Volume increases with signal strength on AM signals such as aircraft. It sounds like a signal level problem. Try removing the antenna and sticking about a 24" length of thin wire into the center of the BNC connector. If it isn't the attenuator or antenna, the scanner may have a problem with the RF amp. Do you have any nearby high power transmitters that have just been added? A TV station that recently changed frequencies could be the problem. If the receiver is overloaded, it can be desensitized. Was the scanner in close proximity to a transmitter that was keyed up. That can blow the RF amp.
 
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BC2001

Jesse
Joined
Oct 10, 2015
Messages
252
Location
Pineville, KY
That could be due to an antenna problem or the attenuator is turned on if the scanner has one. The volume of FM signals is independent of signal strength. Volume increases with signal strength on AM signals such as aircraft. It sounds like a signal level problem. Try removing the antenna and sticking about a 24" length of thin wire into the center of the BNC connector. If it isn't the attenuator or antenna, the scanner may have a problem with the RF amp. Do you have any nearby high power transmitters that have just been added? A TV station that recently changed frequencies could be the problem. If the receiver is overloaded, it can be desensitized. Was the scanner in close proximity to a transmitter that was keyed up. That can blow the RF amp.
I live in a rural area of far Southeastern Kentucky, and there have not been any new transmitters, that I know of. I have used a 2 way radio before, possibly near the scanner. Maybe that's it then.
 

nodak1crdet3

Member
Joined
Jan 5, 2008
Messages
1,359
Location
Detroit, MI
Have you opened up the radio & checked the connections to the antenna? That's what happened to my PRO-97 below. While trying to take a picture of the antenna mount. I noticed the wire broke free again. I hope this helps.

20240318_220911(1).jpg

Chuck
 

tvengr

Well Known Member
Joined
Feb 10, 2019
Messages
9,401
Location
Baltimore County, MD
Have you opened up the radio & checked the connections to the antenna? That's what happened to my PRO-97 below. While trying to take a picture of the antenna mount. I noticed the wire broke free again. I hope this helps.
Also, check that the center pin on the antenna has not broken off.
 

BC2001

Jesse
Joined
Oct 10, 2015
Messages
252
Location
Pineville, KY
I tried the wire in the antenna connector, no luck.

I also opened the radio up and it doesn't appear to be having any issues with the antenna connector.

But, I do have some good news; I found a replacement Pro 404 online for a very reasonable price! Guess I'll likely just use this one for parts (unless you guys have any other suggestions)

At any rate, thanks, @tvengr & @nodak1crdet3 for the suggestions and tips.
 
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