Hints and Kinks

HINTS AND KINKS – by Scotty VK2KE

Speaker impedance

When connecting a speaker to a receiver watch the impedance of the speaker so  that it matches the rig or receiver, if you connect a 4 ohm speaker to a receiver that is designed for 8 ohms, it may overload and destroy the audio amplifier transistors  in the receiver.

Speaker quality

I once used a cheap speaker on a rig in the car and its audio quality was dreadful and made it hard to understand some stations on air while I was driving along. I went to the local electronics store and bought a speaker that was typically used with mobile phones in the car. These speakers have good audio quality and made a huge difference with readability of the stations i was talking to while driving.

Shack acoustics

Be ware of the acoustics of your shack as it will affect the quality of your transmissions.

I have curtains on my windows and carpet on the floor and this reduces reverberation on the shack which  gives much better quality audio on the transmissions.

Coax feeds to antennas 

It is important to have a strain relief loop in the coax at the antenna.  This will save problems with open circuits occurring in the connector at the antenna over time as I have found in my experience.

Noise in the shack

Some stations tend to have a radio or TV going in the shack while transmitting . This gives extra noise on the transmission and is not fair on the station you are working who is trying to hear YOUR voice and you only. 

Also when mobile, close all the windows and this will greatly reduce the background noise on your transmissions.

Safety

It’s important to take care when running 240 volt cables in the shack so that no exposed terminals or connections can be touched by your fingers. Have one main switch that can be turned off in case of any shock or fault occurring.

A good principle is to have all power in the shack coming through a core balance circuit breaker so that any fault or shock hazard is avoided.

Earthing 

A ground stake should be installed just outside the shack and all gear is then connected to that main earth, this will also give some protection in case of lightning strikes.

Antenna switching

It’s a good idea  to have a coax switch what allows the antennas to be easily switched.  I have two coax switches on the line and it allows me to switch the rig to a number of antennas.

Lightning protection 

A lightning arrestor can be placed in the coax line and will give some protection to the rig in the case of lightning occurring in the vicinity ,these are available commercially from an Australian company.

Submitted by Scotty VK2KE

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