0.433Vpp = 0.153Vrms = 153mVrms
That is a lot of RF voltage coming from your antenna!
Or as Mr. Spock would say, "Fascinating!"
Thanks for making the test; good detective work. I also wish you had a spectrum analyzer, to confirm the frequency and check for other possible interference like cell phone transmitters from above TV CH 51.
That is waaaaay too much. It does look like it is coming from WLRX, but why not from WOUL-FM that is 15 dB stronger at +4dBm; they are both in about the same direction? Maybe it has something to do with the gain curve of your antenna. The specs say FM band gain -0.8 dB.
So, 153mVrms = -5.1 dBm in a 75 ohm system; about what you would expect after looking at your FM signal report:
http://www.fmfool.com/modeling/tmp/2...f/Radar-FM.png
Quote:
Originally Posted by chris1379
I have experience in CB and a little Amateur radio (friends) so that helps. I just don't have practical experience with TV in weak signal areas.
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You are getting the experience now. Maybe you can borrow a spectrum analyzer if you have ham friends. If you do borrow a SA, be careful not to blow out the front end with that hot signal. Look at the analyzer specs and use an attenuator if necessary.
Quote:
Originally Posted by rabbit73
Extreme measures are sometimes necessary, even if your equipment is operating properly, if you have very strong EMI.
John Stanley, K4ERO, was able to operate a ham station when he was living at the transmitter site of HCJB in Quito, Ecuador. A 40 meter dipole collected enough RF to light a 100 watt bulb. See Front-End Overload, A Worst Case Example on p214 of The ARRL Antenna Compendium, Vol. 3.
This is where the quad loop antenna was invented (patent no. 2,537,191) by Clarence C. Moore, W9LZX, because of problems with corona discharges from the previous four-element antennas that were fed by high power transmitters located at 10,000 feet altitude in the Andes. The aluminum elements got so hot that pieces melted and fell to ground.
Quad antenna - Wikipedia, the free encyclopedia |
from this original post:
http://www.digitalhome.ca/forum/186-...ml#post1307146
If K4ERO was able to operate a ham station at HCJB and receive signals, I think your chances of receiving at least WOWK are good with the right filters and a good ground.
There are some tests you can do with your 'scope now. Insert a HLSJ, high and common ports, in the coax and take more voltage readings. Try it with and without grounding the coax. You can also try inserting a UVSJ (not the MCM UVSJ), high and common ports, which will limit reception to UHF. You should get a reading from WKAS.
WKAS -27.5 dBm + ant gain 5 dB = -22.5 dBm = 0.02 Vrms across 75 ohms = 20mVrms = 56.6 mVpp if your 'scope reads that low at 545 MHz.