Better bias-t for MLA-30+?

[SpaceForceCmdr]

Is there a relatively inexpensive tee I can buy for my MLA-30+ to replace the stock version? Looking for a lower noise floor. USB powered like stock would be good. Thanks!

 

[ka3jjz]

Did you apply for membership in the FB group I mentioned in a previous thread and answer the questions? It takes the mods a bit of time to check in; that would likely be the best place to find this out

Mike

 

[ka3jjz]

I see that 'eric von lichtenstein' is asking the same question there....

 

[SpaceForceCmdr]

Yep, I posted there at ask, too. Figured between here and there, someone might know. My MLA actually works pretty well as is, but any additional improvements would be good. Sometimes, it actually pulls in weak signals better than my indoor wire.

 

[Ubbe]

It seems more logical to look at the amplifier circuit. The bias-T box have a potentiometer to adjust the level from the amplifier at the antenna to not overload a receiver. Open up the bias-T and adjust that pot for best performance. At shortwave frequencies the noise in an RF amplifier are usually not so important as you have much higher noise levels from the surroundings, like network routers, computers, computer screens and TV screens, mains wirings, power supplies and so on.

/Ubbe

 

[SpaceForceCmdr]

Thanks. I was playing around with this the other night. The attenuator in the bias-T made everything more quiet, but it didn't seem to make much difference regarding SNR. I also played around with the pot on the antenna box, and turned it down just a bit. At full throttle, the noise floor was huge, so I turned it down until it got to a lower value, but the signal still remained strong.

At first I wasn't sure about this loop, but I think I'm actually pretty happy with the results. For the cost, it works well. Doing some back to back testing, I do seem to be getting a stronger signal, and better SNR with the loop vs my indoor, long wire. I replaced the thin wire loop with some copper, and that seemed to increase the SNR just a little. At any rate, it's definitely sturdier and looks cooler! It's up in an eave on my 2nd floor, so probably the best I can do without it being outside on the roof.