Without my Hi-Z 8 and the Waller Flag (on a 40 Ft boom at 95 ft) I would not hear squat on 160. I listen in diversity receive with the K3 and use only the Hi-Z 8 with the IC-7610. However, the IC-7610 is EXTREMELY QUIET!!
73, John, W4NU Atlanta K4JAG 1959 to 1998 Sent from my iPhone > On Dec 15, 2018, at 3:05 PM, Stan Stockton <[email protected]> wrote: > > Thanks, Rick. I think you are fortunate to have a low noise level where > you could actually use your TX Antenna. > > My situation is that if I tried to listen on my transmit antenna I would > only work the very strongest of signals. Typically the noise moves the > meter to about 20-25 over S9 if I listen on my vertical. The best success > I have had is with a Beverage, but whether on any given trip I can put one > up largely depends on whether any of the four or five people's property I > would cross are there and whether they would allow it or complain about > it. On my own property, the only thing I have done is put up a little > triangle with the top at about 20 feet and the bottom wire in the > neighborhood of 30-35 feet. That antenna has about -37 dB of gain. A 15 > dB preamp plus the preamp in the transceiver makes it an OK antenna - good > enough that I have worked about 250 JA stations none of which would have > been worked if I were listening on my vertical. And I am guessing that if > I had a 3 dB improvement in S/N ratio that I would have worked 400 in the > same time period. That antenna has an RDF of 7.7. Always wanting > something better and if I could put up something I could rotate with an RDF > of 11 or so, I would hope to be content. > > Stan > > Stan > > On Sat, Dec 15, 2018 at 1:47 PM Richard (Rick) Karlquist < > [email protected]> wrote: > >> General response, not specific to the Waller Flag: >> >> For a number of good reasons, you should not expect >> a NF below 3 dB for any practical preamp. OTOH, >> virtually all radios have an internal switchable preamp. >> Let's say your radio is really pedestrian, and the >> internal preamp has 10 dB NF. Neglecting feedline >> loss, your preamp gain only needs to be about 13 dB in >> order to the preamp noise to dominate over the radio >> noise. Any additional gain above that will not help >> you "start to hear band noise" but will instead hear >> preamp noise. Some ops like to use additional gain in >> the preamp to make the AGC threshold occur at a lower >> level. This reduces listener fatigue, but does not >> actually produce any newly-readable signals. >> >> If the above isn't correct, can someone give a worked >> example of where a 40 dB preamp would make sense? >> >> FWIW, I tried a Waller loop last year in the 160 meter >> contest. It was quite large (I have plenty of space). >> It seemed to be working OK in terms of being directional, >> but it almost never improved the readability of any >> signals vs the vertical. IOW, aiming it at Japan didn't >> help work JA's, except to the extent that it reduced >> stateside QRM. On a clear frequency, there was no advantage. >> >> 73 >> Rick N6RK >> >>> On 12/15/2018 11:15 AM, Stan Stockton wrote: >>> I am curious to know if anyone on here has scaled a Waller Flag to a >>> smaller antenna and had any success with whatever might be available for >>> preamps to bring the gain up enough to start to hear band noise. >>> >>> At my location on Cayman Brac I could probably get by with a 20 foot boom >>> but not much larger. According to my model, one with a 50 foot boom is >>> about -48 dB, one with a 30 foot boom is about -65 dB and one with a 20 >>> foot boom, like I would lilke to put up, is about -79 dB. >>> >>> I guess a lot to do with how successful the antenna might work for me >> will >>> have to do with how much preamplifier gain I will need at my particular >>> location to start to hear noise. I wanna use it on 160, 80 and 40 and >> the >>> gain of the 20 foot boom one is enough for 80 and 40 using a 30 or 40 dB >>> preamp. >>> >>> Any help would be appreciated. >>> >>> 73 and Merry Christmas...Stan, K5GO/ZF9CW >>> _________________ >>> Searchable Archives: http://www.contesting.com/_topband - Topband >> Reflector >>> >>> >> > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
