Bjorn, Tim: Thanks for your comments.
I don't have much time to play with the antennas until the weekend, but I did manage to hook up an SWR Analyzer. The analyzer says 1.5:1 at 1820 Kc (35 ohms R). So, there is an antenna out there. A need to clarify that the noise level is the same between the INV-L and EWE when I use the EWE preamp. Without the preamp on, the EWE noise level is almost nonexistent. A did notice something. With the coax cables on my other HF antennas, when I unscrew the shield connector and break shield contact the noise rises significantly but goes to nothing when the shield is screwed back on. This does NOT happen when I disconnect / reconnect the PL-259 shield connector on the cable. Re-orienting the EWE to be "in front" of the INV-L isn't possible right (I have only an acre). What I may do is take down the EWE and put it up in the front yard where it will point N/S. I really would like the EWE for EU DX, but if it's not working, then a N/S attempt may be in order. 73 Mark K3MSB On Thu, Dec 10, 2015 at 9:31 AM, Tim Shoppa <[email protected]> wrote: > I would like to concur with SM0MDG's comments about receive coax > connections. I betcha the OP's system is leaking in at levels way higher > than the Ewe actually produces. I know everyone loves to detune their > transmit antenna, but there's no way an Ewe should sound noisier than the > inverted L. > > A reversible array is far and away the best way to convince yourself that > you have a working receive antenna system. If you reverse it and nothing > ever changes, well, you're listening to some other antenna! Some (e.g. YCCC > array) are supposed to be far more sensitive to near-field metal objects > than others (e.g. K9AY loop) but even then I'm sure you'll be able to find > a convincing F/B on known BCB stations once you have stuff working right. > Another useful beacon is W1AW code practice at 1802.5. > > Tim N3QE > > On Thu, Dec 10, 2015 at 9:19 AM, JC <[email protected]> wrote: > >> Hi folks >> >> I would like to add some comments to receiving antennas issue. Any >> resonant thing (wire, cable, rotor cable tower, TX antenna...) will >> interact with the RX antenna if they are in the same polarity, different >> polarity has 27 dB or more of isolation due the polarization itself. >> >> The inverted L is easy to detune, just open the wire from the coaxial and >> check the noise on the EWE. The noise on the RX antenna needs to decrease >> one or 2 S units. However, it is possible you will not see any difference. >> The reason is that you may have another point where common noise is >> deteriorating the directivity of the RX antenna. If it work, just add a >> relay for detuning the Inv L during RX. >> >> The integration with the inverted " L " TX antenna is the easy one do fix >> the others resonant "things" could be difficult to recognize. Example, if >> you have a low dipole or elevated radials, these "things" will destroy any >> directivity of nearby RX antennas, and nearby distance on 160m means 300ft >> or more, one wavelength. Rotor cable, VHF or other's 120ft feed lines could >> be resonant and a good reflector for noise and re-radiate them too. >> >> Lack of good ground (or no ground at all) is receipt for failure on RX. >> Running the cables outside the tower and far from the ground is the >> preferred way to screw things up. >> >> I am following every installation of my WF's and there is an issue very >> frequently found. It is bad connectors contact with the cable shield. Cold >> solder, no solder, little copper wire on the braid. One single point with a >> bad shield can ruin you RX system. >> >> Doug Waller when he build the first WF was very disappointed with the >> results until he found a RCA connector with one RCA ear not contacting >> the preamp input RCA female. Just one little gap in ear with no contact was >> enough to leak noise into the preamplifier input. After fixing the bad >> contact, the RX antenna started to work with good directivity. PL259 or a F >> connector with bad contact with the braid can cause several S units of >> noise. >> >> Spending big money on the radio and do not care about the quality of the >> connectors used for RX is no sense. >> >> Open frame relays (not coaxial relay), open contact switches, plastic >> boxes are the most common points to add noise and destroy the directivity >> pattern. >> >> Running cable outside de tower and ground them at the base is not a very >> popular solution. It is hard to run the cables inside the tower they say. >> As a result RF is everywhere in the shack. No solution for that too. >> >> I am just trying to help, there is no free beef regarding good RX systems. >> >> 73's >> JC >> N4IS >> >> >> >> >> >> _________________ >> Topband Reflector Archives - http://www.contesting.com/_topband >> > > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
