TK-780 Receiver noise

[KenwoodGuy1710]

I've got a TK-780 that refuses to be quiet with the antenna connected. All I hear is constant static across the bulk of my channels. If I unplug my antenna, silence. I am not in a high RF environment, but I have traced the source of the noise to my television that is few feet away. The only way to stop the static is to turn off my TV. I have moved my TV about 10 feet away and it still causes this interference. What is the best way to get rid of this interference? (Other than turning my TV off) I have changed receiver sensitivity and squelch settings but I have to effectively make my radio deaf before it will mute. What's the best course of action? What kind of filter would solve this? Also, the antenna is outside and away from any sources of interference. Thanks all!

 

[tweiss3]

Do you have a Tone or DPL set?

 

[a417]

I am not in a high RF environment, but I have traced the source of the noise to my television that is few feet away.

...oh, but you are.

What is "the antenna" you speak of? If the signal is only overloading the RF front end (from your terribly high RFI TV source in the same room) only when your antenna is connected...it would stand to reason that you need to reevaluate the materials & composition of your antenna & cabling.

 

[KenwoodGuy1710]

Do you have a Tone or DPL set?

I'm able to mask it with a tone on a few channels, but there are channels that do not use a tone. This is where my problem comes to light.

 

[KenwoodGuy1710]

...oh, but you are.

What is "the antenna" you speak of? If the signal is only overloading the RF front end (from your terribly high RFI TV source in the same room) only when your antenna is connected...it would stand to reason that you need to reevaluate the materials & composition of your antenna & cabling.

My antenna is a 1/4 wave on a brand new mag mount outside of the building. The antenna isn't the issue. I can simply touch the SO239 on the 780 and my interference comes back without the antenna hooked up at all.

 

[a417]

My antenna is a 1/4 wave on a brand new mag mount outside of the building. The antenna isn't the issue. I can simply touch the SO239 on the 780 and my interference comes back without the antenna hooked up at all.

...because any connection to that antenna port just floods that RF front end with noise...even your finger. The problem doesn't seem to be your antenna, it's any antenna.

Is it quality shielded antenna feedline cable? A brand new mag mount may be brand new, but the potential for ****ty materials and bad connectors and no appreciable shielding may be exacerbating your issue.

I'd bet that if you had proven quality shielded cable w/ an appropriately connected feedline and you got the antenna a bit more up and a bit farther from your TV, that unit would stop doing this.

 

[Russabbey]

Another thought here. Get yourself a couple f torrids, and warp the TV's power cord and your radio power cords inone also. That may or may not work, but it's worth a try.
A mag mount on an AC or heatpump is not a good antenna. Weather new or not, the materialls used in the making of the antenna matter big time. I would bet you that the antenna is on a piece of metel outside and you're using something like RG-58u coax, get a good piece of RG-8x or better still some LMR-400 or RG-223 and you will illiminate most if not all the noise. Try the torrids first, then the coax then if none of these work, you may want to get a different radio to try in the house.

73
Russ Abbey, N4MAV
EM97ua

 

[wwhitby]

I've used a TK-780 for about 9 years, first as a mobile and now as a base radio. The 780 has a very "hot" receiver and will regularly pick up RFI from other sources. I had to shut mine off when going through drive throughs, toll booths, by large digital signs, etc., because the squelch would open on frequencies not using a PL or DPL. Sadly, there's also a lot more RFI these days, especially on VHF.

The other thing it could be is that the previous owner may have fiddled with the adjustments in the KPG-49d to make it more sensitive than it should be. You would need to have the alignment checked to rule that out.