[Elecraft] KX-3 Powered speaker suggestions?

[Jim Brown]

On 8/3/2020 6:58 PM, Ron Manfredi wrote:
> I tried both an amplified Motorola speaker and a small MFJ unit, but 
> when using SSB (10-15 Watts) at home into a beam or into a dummy load I 
> can hear myself quite clearly in the speaker, so RF is getting in somehow.

Powered speakers have a power amplifier built in, which are notorious 
for RF susceptibility. The causes are typically poor shielding and/or 
Pin One Problems, but things we do wrong (or fail to do) in the shack or 
with our antennas can put lots of RF into a powered speaker, making it 
more likely for RFI to occur. Motorola products are generally designed 
for UHF 2-way applications, and are unlikely to have been designed for 
use around HF transmitting antennas.

What antenna system are you using? If it's some form of end-fed wire 
ending in the shack, does it have a counterpoise? It should. If up in 
the air with a feedline, does it have a serious common mode choke at the 
feedpoint? How is your station bonded? How is it grounded?

Station grounding and bonding is covered here.
http://k9yc.com/GroundingAndAudio.pdf

RFI is covered here. The chokes recommended for killing noise would also 
appropriate for cables feeding the speaker (both power and audio). 
http://k9yc.com/KillingReceiveNoise.pdf

Transmitting chokes are covered here. http://k9yc.com/2018Cookbook.pdf

73, Jim K9YC