Basic antenna question

[KC3UEN]

Wondering if someone can explain what is happening to me. Recently got back into amateur radio after an absence of about 50 years. Before I got my license, I was using a long wire antenna for my Drake R-4A and was getting good reception (wire connected to center conductor of RCA plug). I then got a T-4XC transmitter and because of neighborhood restrictions, put up an end fed antenna (Hyendfed 4 band) which goes from a tree in the back yard to the second floor peak of my garage (equipment on the 2nd floor). Coax goes down to a lightening arrestor/ground rod and back up to the second floor, to transmatch, transmitter and ultimately to receiver. The Drake has an RCA phono plug for the antenna. If only the center conductor is making contact in the jack, signal is much stronger, but much more static. If fully into antenna jack so that the shield is now connected to the chassis, interference is much less, but signal strength is also way down, to the point where I'm losing some signals I can hear otherwise. Same thing occurs if antenna goes directly into receiver, eliminating the equipment in the middle. I have a feeling I'm missing something very elementary, but can't put my finger on it. Any help appreciated.

Conrad

 

[RFI-EMI-GUY]

I would check the coax for a short, an open or water intrusion. There could be a problem there that affects the normal signal path from the dipole through the balun. In that case, the signal is either shorted to the coax shield or capacitively coupled. Have you checked VSWR?

Connected properly the antenna should favor signals pertaining to its dipole orientation. If you disconnect the coax shield, the entire feedline and the end fed antenna behave as a long wire antenna. So if the orientation of the coax is different than the dipole, there will be signals stronger in that orientation. Noise may be higher as well.

 

[trentbob]

So almost 60 years ago I used to do SWL, as a young kid. I had a 200 ft copper wire antenna, with a jumper into my room compliments of my father and uncle, both hams.

What was different then compared to now is all the RF noise we have now that we didn't have then. We didn't have all these huge towers everywhere. They simply didn't exist nor did the noise from everywhere it comes from now.

All we dealt with was the incessant jamming from the USSR. Food for thought. Welcome to radio reference. You're in the right place.