"Hum" from radio channel into mixer...

[N0WY]

Hey all,

I have waded into the land of dedicated audio equipment for my amateur radio equipment and am amazed by the reports I am receiving from others.

I do have one problem I have yet to work out and was wondering if anyone had any ideas...but first let me explain what I have setup, as I am sure that would be the first question asked of me.

Yaesu FT-857
LDG YT-100 Tuner
Behringer 1622FX USB Mixer
iPlus by W2IHY
Heil PR-781
Yaesu FP-1030a Power Supply

I am thinking the issue is that I do not have the power supply, tuner or radio grounded and I have heard that that could cause a hum. My issue is that I am in a 2nd story "office" in my house and running a ground that long would just turn it into another antenna.

So I am wondering what I can do to work on getting rid of the "hum".

Thanks so much,

Michael

[NA4IT]

Two words... isolation transformer. Between the audio gear and the input to the radio.

[N0WY]

So would one such as this work?  My audio path to the mixer is from the radio ext speaker 3.5 mm port to xlr port on mixer.  On the return, the mic is ran through the mixer to the iPlus....FYI.

http://www.amazon.com/Cables-To-Go-40000-Transformer/dp/B0047AKVYO/ref=sr_1_15?s=electronics&ie=UTF8&qid=1332120024&sr=1-15

[KG4NEL]

In A/V stuff, the creme-de-la-creme of 1:1 iso transformers was Jensen Not cheap, but they killed any ground loops while keeping things balanced.

RadioShack used to sell raw 1:1 isolation trafos, but I'm not sure if they do anymore. If you have a music store or a Guitar Center nearby, might be worth a look - a passive direct box would do it too.

[KB4MB]

Buxcomm sells them - and they have premade 1.8" jacks as well (just grabbed you the 1:1 solder yourself version)

http://www.packetradio.com/catalog/index.php?main_page=product_info&cPath=13&products_id=2304

Radio Shack still sells them, but you have to find an old store that stocks them - otherwiser mouser or digikey still do as well.