Topband: NCC-2 remarks
I have one here and would not be able to do much on 160 without it. Patterns depend mostly on what antennas you hook to it. I have tried short verts, was not happy. Now use 2 aperiodic loops which look toward Europe. They are 100 feet or so apart. Works well, and I use this setup as follows. I watch the baseline on my P4 scope and adjust the NCC for the lowest baseline, which is my overall noise level. That often cuts both local and distant crud. This gives me the best chance of hearing in any direction and almost always is a big help. I compare signals between the NCC2 and a regular K8AY loop setup. If I had a better location I'd make a set of loops looking various directions but that is not possible here. The NCC2 is great mostly because it is very stable and can be set for repeatable results. I've messed with it on local BC stations and what one can do with it is often amazing, but mostly on ground wave signals in daytime. Nulls may be deep but arrival of signals via higher angles keeps things in flux. The NCC seems to be almost overload-proof. Yes, if the signal you want is in the same direction as your QRM/QRN you are working against yourself so to speak. That's true of all RX antenna setups. de K8RYU _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Hi Z amplifiers for 160m
Lankford's stuff works great. I have used his antenna which does NOT use a preamp.it's only suitable for situations where match to the feedline isn't critical, but it sure is great to not have any preamp outside. de K8RYU From: Topband on behalf of Mikek Sent: Thursday, March 12, 2020 7:29 PM To: topband@contesting.com Subject: Topband: Hi Z amplifiers for 160m I'll stick my neck out and suggest Dallas Lankford's '2 FET amp'. He designed it for phased loop antennas for the MW band. I believe it will work to at least to 9 MHz and maybe to 30 MHz. The specs High input Z, ~100 ohm output Z. He lists input intercepts: IIP2 = ~ +88dbm and IIP3 = ~+41dbm in the MW band. The webpage has some noise measurements on pages 3, 4, and 5 that were over my head. This page has more than just his amp but enough so you can understand it. If anyone has an interest, I have some more files in my computer. > https://www.okdxf.eu/lankford/Hi%20Z%20PPL%20Loop%20And%20Flag%20Arrays.pdf I have a plan to put a matching transformer and a Hi Z amp on my antenna with relay switching, so I can do a real A, B, comparison. If you have any advice on implementing that or advice about common mode filtering, I'm listening. Better relay suggestions would be appreciated. Mikek KF4ITA _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: 160 Activity
QRN still at summer levels here in Ohio. Has been especially bad with the storms that have passed thru the south. The lightning static from them is single hop to most of the eastern US. de K8RYU _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Desktop power supplies
It is my opinion that there are two kinds of switching power supplies---the kind that are messing up your radio today and the ones that will at a later time. I believe they are not compatible with HF radio at a fundamental level, thought we must learn to live with them. Two instances...one noise related, the other not. A few years back I setup a packet node at a remote BC location, and was blessed with a high quality switching supply. Every time the radio was keyed, the supply would sense the load increase as a short and briefly pulse the DC output. This reset the packet controller, which created several trips to the site before I scoped the DC and figgered out what was going on. In the second instance, this past field day somebody managed to get a switcher hooked up to our 6M radio without my knowledge. When the radio was keyed, the noise from the normally quiet supply clobbered the adjacent SSB station. Reason: The supply did not like the square wave from our generator (rather than the utility sine wave) and the switcher would panic when the load was high. Problem not apparent on the 6M or HF radio while 6M was receiving...only a couple amps load. Never would have thought of those problems. Switching power supplies are very sneaky as well as potentially noisy. They work well with steady loads under ideal conditions. They work well when new when all the line-filter caps are in tact, but the quality of those little caps isn't always the best and they get popped at the worst time. Switchers are a fact of lifebut any time you can avoid one on your operating table, I say do it. Same is true of the little curley-Q lightbulbs (with a switcher inside)... One man's opinion de K8RYU _ Topband Reflector
Topband: BOG Rx antennas
I have a couple of those here, about 150 feet long and they have at times surprised the heck out of me. My best one is made with very fine wire...2 strands of #26 I think it is, maybe #24, telco crosscut wire it was. It is about 150 feet long and has given better results than those I have had made with heavier wire. My reference is a K9AY loop, which I have been using for years. Soil conductivity here is about as bad as it gets. I have to replace the wire every year or so when something breaks it. All the BOG's have very low signal output, require braid breakers to keep the power line away, and fail to work at all if the ground is snow covered or very wet. I have a theory: I think the fine wire works better because of less capacity to the soil. I also think that if the fine wire were installed in a plastic tube, say thin-walled water tubing, the things would work even better. That would put the wire, on average, say a half-inch above ground. I have never tried that design, but maybe I will some day. de K8RYU ___ Stew Perry Topband Distance Challenge coming on December 29th.
