Day 4: Testing and Redesign

 

OMG is the best way to describe how well the receiver works.  I am seeing DX roll in from all over the globe on all bands.  This morning I saw Algeria on JT65.  I’m even hearing signals on 160 meters at night.  I had never heard any JT65 station on 160 before. I am thrilled with the first results.

We got Internet access hooked up and to the surprise of all the system worked on the first try for receive.  At home I pressed the ON button and the receiver came alive.  But then came time to transmit.

I tried transmitting and the SWR was infinite.  The auto tuner in the rig flashed an error.  Loose cable?  I hadn’t retuned the PAR EF-20.  Could it be far enough off?  Time for a trip to the site.

At the site I noticed I could wiggle the coax and get different results.  Bad connector on the coax. I could see the connector was soldered but it appeared to be a cold solder joint. Returning home I made up an entirely new cable and made sure the connector was hot enough to melt solder on it’s own.  No cold solder joints now.  I drove back down and replaced the cable.  I also re-tuned the antenna to dip the impedance exactly at the JT65 frequency of 14.076 MHz.

Interference from the solar controller was now noticeable.  I snapped on some toroids and that quieted the noise considerably but not completely. I also notice some birdies caused by the Internet receiver.  Back home and the SWR is now very low.  The rig is acting normal now.  Time to try the first contact.

The other shoe dropped when I cranked the power up to 25 watts and tried to make a contact.  “RF in the shack” crashed the remote.  I had to drive down and reset it.  Upon arrival I discovered all of my equipment was still running.  It was the Internet receiver that had locked up from the RF.  Back to the drawing board.

My first trial at fixing the problem will be to add more toroids but more importantly I will separate the antenna away from the equipment location.   I ordered 100′ of coax to allow the antenna to be relocated.  When the toroids and the coax arrive I will find out if this helps both the EMI to my receiver and the RF into the Internet receiver. Check back for the update on the results.

coax

Meanwhile I am just listening and comparing received signals with the RF Space Cloud-IQ sdr remote receiver I have access to.  Results so far are neck and neck.  Many stations have an identical SNR report on both units.  A small per centage have different readings and some drastically different readings.  Speculating I would say that’s the different polarization between the vertical antenna on the Elizabeth receiver and the horizontal dipole on the Cloud-IQ.

 

 

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