rx320d Antenna

[SCPD]

Good evening all. I have a ten-tec rx-320d i would like to redo/redesign my shortwave antenna. I have a funny feeling i have it all wrong. This is what i have now. tentec rca into rg6u out to grounding block from the block also rg6u to pl239 9:1 balun then a 75ft endfed inverted l copper wire. I get a lot of RFI no matter what radio i use. I would like to know what would be the ideal setup. Should i replace the tentecs rca input with a bnc female connection and use a different coaxial cable. Should i remove the ground block and go right into the balun. Should i remove the balun and keep the grounding block. I would like to redo my shortwave antenna and try to get it correct before i sell off my ten-tec and give up on shortwave. My reception is very spotty. Please help me.


Mike

 

[ka3jjz]

First do some homework and find out where the noise is coming from. Cable modems and routers are notorious for being dirty, but that is far from a complete evaluation. Use a handheld with no squelch and as little antenna as possible on, say VHF air freqs and start sniffing. You may also need to use an old AM radio (a Walkman is almost ideal) as a sniffer.

The antenna, I suspect, is fine in and of itself. The best thing to do with a HF antenna is to get it as far away from the house as you can. The other thing to look at is the 9:1 transformer itself - or rather, the connections to it. Some designs I've seen require the transformer to be grounded. Did you wind it yourself or buy it commercially, and if bought, from whom? Are you running your coax right near your modems or routers? If so, get it away from there.

Keep in mind that there is a certain amount of noise from the 320 itself (indeed, when Larry Magne did his review, he noted that he couldn't do a proper evaluation of the filter complement partly due to noise within the receiver).

There are a great number of possibilities here. You need to start being a detective. Turning certain appliances off then turn them on one at a time, noting when the noise level rises, is a tried and true method, but be aware that you could easily have more than one appliance besides a cable modem causing issues.

73 Mike

 

[ka3jjz]

Here's something else to look at - are you getting noise from the AC itself?

Universal Magnetic Balun is specifically designed to reduce noise from the antenna

73 Mike

 

[SCPD]

I tried for many many months to track down the rfi and still can not locate it. I shut off the main break to all 3 apts in my house that did not help. I walked around my neighborhood with a handheld and that did not help. What i did today was add another ground block and ran a single ground wire to my cold water pipe. Before i had a dual grounding block 1 for hf antenna and 1 for scanner antenna going to a single grounding rod in the gound. So far it seem to be a little better but not much. Im thinking maybe i should go with a active loop on a rotor and see if that help if not then im going to sell my rx320d

 

[ka3jjz]

Did you try physically separating the 320 from the PC? Don't keep it nearby - sometimes a separation of 2-3 foot may be all you need. I run indoor antennas with my 320, and it's on the other side of the desk. I get very little junk from my PC - of course, there are other noise sources in a condo, but it's a step in the right direction

If you do decide to go with a loop, you might want to start inexpensively with a nice skyloop - that way your 9:1 transformer (which we still don't know whether you bought one or wound it yourself) doesn't go to waste. And I would pay attention to that Wellbrook link as well 73 Mike

 

[SCPD]

My 320 is about 6 ft away from my desktop pc. It is next to my alarm clock and bct15x, The balun was purchased from ebay. direct link here

9:1 Longwire, Balun, Unun, Adapter, Shortwave, Slinky - eBay (item 260678139804 end time Dec-13-10 11:14:50 PST)

Im going to look into the skyloop now. Thanks for taking the time to try and help me with this on going issue

Mike