195
« on: September 02, 2018, 1559 UTC »
This is based off an observation i made trying to hook my H-800 directly into my afedri while on a road trip. The receiver's HF input is 50 ohm per the specs, and the H-800 uses RG-174 (50 ohm) so I didn't anticipate any problems. HOWEVER, the power supply box for the H-800 (the antenna probe receives power over coax from the box, and the connection to the receiver is on the box) uses RCA-type connectors for some reason while the afedri has those tiny SMA connectors. No problem i thought, since i have a spectrum of various adapters. So i hook everything up, with an RCA to F-type coupled to a F-type to SMA which is plugged into the afedri (I did NOT have a RCA to sma hence the workaround). Long story short..the receiver was deaf as a bat. Thinking there might be a problem w/ the H-800, i decided to rig up an improvised LOG using the RG-174 as it was the only coax i had. Still nothing...which was very odd considering i've had very good luck with LOG from that remote location before. The coax was visibly intact and had good conductivity between the ends. I finally considered the option that there might be an issue w/ the adapters and did an improvised connection (e.g. cut the RCA off the coax and directly made conductivity between the coax and the SMA connector on the radio) and BOOM! everything working great.
So...the adapter seems electrically fine in terms of conductivity. My working theory was that there was a problem with the 50 ohm-75 ohm-50 ohm mismatch between the coax, the adapters, and the radio. Does that make any sense at all? If so...why do i get OK results going from an antenna through 75 ohm RG-6 and into the radio with an F-type to SMA connector?
Show Posts
