6300 (before starting SmartSDR) causing desense of nearby receivers?

Howard -W6HDG

I'm about 8 days in using the new 6300 and I have an odd issue.  I'm A/B'ing two radios - the 6300 and my Yaesu FTdx3000.  If I'm on the Yaesu and turn on the 6300, it causes about a 3 S unit desense of my Yaesu as soon as the Flex gets to a certain point in the bootup start cycle.  I can disconnect the coax switch from the Flex entirely and it still causes the issue.  But as soon as I start SmartSDR even with no coax attached to the Flex box....BOOM - my Yaesu comes back to life. 

Is the non-software controlled 6300 radiating RF?   Howard W6HDG

James Kirk

It is **** the RF right out of that Yaesu, Resistance is futile.

Steve-N5AC

This is just a guess, but are you sharing a power supply? It's possible that power supply ripple caused by the load from the 6300 is causing issues for the Yaesu. What kind of power supply are you using? It doesn't seem likely to be a radiated RF issue since the closer receiver to any RF from the radio would be the radio itself (6300) and it doesn't hear anything.

Howard -W6HDG

Thanks for the response. They do share a supply - a linear RS35M. What's crazy is that the desense of the Yaesu resolves as soon as SmartSDR is started even if no coax is attached to the Flex. The Flex seems to be radiating at boot up until SmartSDR is started.

KY6LA_Howard

Howard borrow a second receiver NOT attached to that power supply. Shut down the Yaesu. Start the 6300. Do not start SmartSDR Listen for RF. I do have a noise antenna RF sniffer you cud borrow but I won't be around to July1st.

Mike KD2CJJ

Put an AM radio next to it tuned to a local station and see if there is any effect.

Steve-N5AC

Could you also run the experiment with your computer completely off? Understandably you will not be able to see SmartSDR run in this case, but if it is not the computer, you would still see the floor rise initially. The best way to find things like this are to assume nothing and just start adding and subtracting things from the equation until you locate the thing that causes the issue. FYI, we run all our radios through emissions testing and the FLEX-6000 series has been the quietest of any radio we have ever tested. Those of you that have seen the actually radio inside have seen that all of the processing is inside of a metal shield (Faraday cage). The receiver input is just outside the shield so any noise from inside the box would be very visible in the receiver itself if it escaped. The receiver is, however, VERY quiet.

Howard -W6HDG

I ran the Flex from battery power this morning and the issue did not recur.  I then reconnected the power supply and the issue did not recur.  So chalk this up to ghosts.   I'll be darned since it was so reproduceable yesterday.  Sorry for the false alarm.  

Steve-N5AC

For more details on this issue, see this thread