SSB getting into electronics

[1018weatherman]

Hello,

Every time I key up and speak into the mic it gets transmitted into my equalizer and mixer when it isn't even plugged in at the input, and sounds terrible. I would like to be able to incorporate these two items into my base setup but am having no luck. Would this be something that a low pass filter would cure?

 

[KK4HBW]

Hello,

Every time I key up and speak into the mic it gets transmitted into my equalizer and mixer when it isn't even plugged in at the input, and sounds terrible. I would like to be able to incorporate these two items into my base setup but am having no luck. Would this be something that a low pass filter would cure?

A low pass filter allows low(er) frequencies to pass, while attenuating high(er) frequencies. From what you describe, they will not help you. It sounds like you've got common mode current where it shouldn't be. The problem is most likely with your antenna & feed line.

Look into ferrite chokes or other baluns...

 

[KK4HBW]

Hello,

Every time I key up and speak into the mic it gets transmitted into my equalizer and mixer when it isn't even plugged in at the input, and sounds terrible. I would like to be able to incorporate these two items into my base setup but am having no luck. Would this be something that a low pass filter would cure?

Thinking about my post; I made some assumptions without all relevant information... it's _possible_ that a filter would cure your problem. I'll just defer to someone else for a good answer on this one. Sorry about that.

 

[WA0CBW]

What you describe is sometimes called "RF in the Shack" and can be caused by many things including the antenna, coax, amplifiers, and improper installation methods. A little more information about your installation would be helpful to diagnose the actual causes. Some things you can try is to make sure all your equipment is connected together with a single point ground (not daisy chained). Make sure the antenna and coax are working properly (i.e. low SWR) and that the antenna is outside and not in the same room as the equipment. Also check to see that the radio is not emitting any spurious emissions and that the modulation is not above the normal ALC limits. Be aware that some equipment isn't designed to reject strong nearby RF signals (i.e. your equalizer and mixer).
BB

 

[majoco]

WA0CBW said

What you describe is sometimes called "RF in the Shack" and can be caused by many things including the antenna, coax, amplifiers, and improper installation methods.

I agree +1 - everything should be in metal enclosures firmly grounded and all leads screened - including speaker leads as a last resort.

 

[rescuecomm]

As previously noted, your antenna SWR is too high causing RF in the shack. Either a bad connector, coax cable or the antenna itself.

Bob

 

[LtDoc]

I didn't see an SWR mentioned, do you mean in this thread or in another one?
- 'Doc

 

[rescuecomm]

I didn't see an SWR mentioned, do you mean in this thread or in another one?
- 'Doc

Generally a high SWR means alot of power is reflected back to the radio and other devices. The OP did not indicate that he had measured it. A good idea for starters anyway.

Bob

 

[LtDoc]

I don't think I'd blame SWR as the culprit till you know that there's an objectionable SWR present. It certainly isn't a sure thing, only a possibility among many.
- 'Doc

 

[jhooten]

SSB what? CB?
How much power?
Antenna location?
Type of cable?

 

[JayMojave]

Hello W1018:

I would think NO to the low pass filter. The Low Pass filter will significantly reduce multiples (harmonics) of your transmit frequency or unwanted spurs above 30 MHz, which is a good thing to have.

But it sounds like your experiencing RF Overload condition, that is a strong and near by RF Field of Energy getting into your equipment there. The low pass filter will not help in this case.

You can move the antenna up or even farther away from your location which will help but may not be the cure. Its possible to install RF Toroids or snap on Toroids from Radio Shack over the input and even output wiring. Making sure the antenna mast is grounded is a good thing.

The ARRL sells a book on RFI and it has a bunch of great info in there.

I have a FM Broadcast Antenna mounted on my CB Antenna Mast about 3 feet from the bottom of the CB Antenna, and yeah I get RF Overload into my FM Stereo Radio, but the FM Antenna Coax I rolled into a coil of about 10 turns on about a 10 inch diameter, and installed the Radio Shack snap on Toroids, over the FM Antenna Coax and RF Overload interference is gone.

Theres plenty of articles on RFI on the net that can help out.

Good luck, please let us know how you make out......

Jay in the Mojave

Hello,

Every time I key up and speak into the mic it gets transmitted into my equalizer and mixer when it isn't even plugged in at the input, and sounds terrible. I would like to be able to incorporate these two items into my base setup but am having no luck. Would this be something that a low pass filter would cure?

 

[JayMojave]

Hello W1018: One more thing you didn't tell us, is what your running for a radio, amp, meter ect, and antenna set up / installation.

Jay in the Mojave

Krediatials:
New LH head gasket on 1964 Buick
Incedo loud 80 watt PA System in 4x4 truck, and not of this world bright aircraft landing lights
5 college credits, 3 for passing traffic school and 2 for leaving early