getting rid of two-way radio interference?

Some months back, there was an excellent article on dealing with EMI/RFI on the Audioholics site by Dan Banquer. It`s not easy but can be dealt with.

I'm a ham (WB5KKO) in addition to an audiophile. Most of the time when gear picks up a radio transmission it's the fault of the gear, not the transmitter. FCC regs say that as long as the transmitter is operating properly (and they usually are), then the elimination of interference is the responsibility of the user of the gear.

Most hifi gear is not really well shielded against stray RF. This would raise the price significantly.

The biggest point of entry for stray RF is the power line. If you're not using a good power conditioner consider having a tech install some bypass capacitors on the AC input of the Rogue and any source equipment feeding it.

Be sure all your interconnects are shielded, and take special care with your phono front end, if any. Due to the small voltages and high gain used, the phono system is particulary susceptible to RF pickup.

If your interference happens on all sources and is not affected by the volume control, then the Rogue itself is the culprit and you should focus your attention there.

If your interference happens on all sources and is not affected by the volume control, then the Rogue itself is the culprit and you should focus your attention there.
Ghostrider45

It also can be the speaker cables and the speakers. I have seen instances where the amp is turned off and the Ham could still be heard faintly through the speakers.

Ghostrider45, why is it never the Ham operator's fault and always the audio system's? With all the commercial radio stations transmitters RF in the airways they do not come through audio systems like a Ham Operator's RF. Could you please explain?

Jea48 - as long as the transmitter is operating on legal frequencies, using legal modulation, at legal power limits and from a legal location then the transmitter owner has fulfilled his responsabilities under FCC regs. The ham license typically identifies the home address of the licensee as a legal station location, and mobile and portable operation is allowed as well.

The owner of the affected equipment is responsible for ensuring that it is not affected by legal transmitting equipment.

The wisdom of this is that the transmitter operator is not accountable for poorly designed, implemented, and installed electronics that he has no control over. As pointed out above speaker and interconnect cables can pick up stray RF. How can the poor transmitter operator be responsible for interfereing with a system that foolishly uses unshielded interconnects?

When you consider that a legal CB rig puts out at most 4 watts of RF (5 watts DC input) on 11 meters, there's really no excuse for any device being affected. Remeber that the signal strength follows an inverse square law - double your distance from the antenna and the signal will be a quarter of its original strength.

There's a bit more excuse for ham rigs. The legal limit is 1000 watts DC input (2000 watts PEP for SSB), though most rigs run much less. The ham bands also span a large frequency range, from 160 meters (VLF) through VHF to UHF. Most VHF (2 meter FM for example) and UHF rigs run fairly low power, in the 1-50 watt range.

Nonetheless with good engineering and construction most electronics can be made pretty bulletproof to stray RF. Most manufaturers including high end cut corners here to save costs because most users will never face the problem.

Why is not the ham's fault???

Because most of them operate within FCC limits.

CB radio types......OTOH........are notorious for flaunting the law. They should be fined when caught. Problem is, they are almost never caught.

Most audio gear has little, if any, design consideration to minimising the effects of EMI. I am a manufacturer, as well as a "ham" and an audiophile. There is a good chance I speak with authority on this subject.

AC line cords......interconnects....speaker leads.......all make for good antennas. Any one, or a combination of them could be the source of your misery.

As an engineer, I would first want to know the transmitting frequencies, and the field power. But as that is not something you are likely to be able to supply us, let's try a different approach.

The next time you experience an extended period of interference, turn off your system, and disconnect the amp from the preamp. Place a shorting plug in the input of the amp, and turn it back on. Let us know what, if anything, comes out the speaker that does not belong. That is the first step to determine waht piece of gear we need to operate on.