ad: vanity

Which amp: 30L1, AL80, AL-811H

Discussion in 'Amateur Radio Amplifiers' started by K7JOE, Sep 3, 2018.

ad: L-HROutlet
ad: l-rl
ad: L-MFJ
ad: Left-3
ad: Left-2
ad: Subscribe
  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    It takes time and cooperation from friendly neighbors.

    My neighbor had a large fish tank with a heater that cycled on and off and drove me nuts, even though it was about 120 feet away (noise probably backed into the power line and radiated from there).

    I offered to buy him a new heater after demonstrating to him that it was his heater causing a big noise problem (I just used a portable radio to demo this). He apologized and bought a new heater on his own. Problem solved. Small steps, one by one...
     
  2. K6BRN

    K6BRN XML Subscriber QRZ Page

    Steven:

    I hear your annoyance. Not trying to be a troll, so please bear with me as I play devils advocate just for a moment to explore your thought.

    There is a general assumption that link quality, when making a contact, is reciprocal. But that has never really been true, now or in the '60s. The differences are driven by the following items, and more...

    1. Differences in noise backgrounds at each QTH - as you commented
    2. Differences is propagated adjacent channel interference OR channel overlap
    3. Differences in antenna gain and directivity, including takeoff angle
    4. Differences in TX power
    5. Differences in attenuation over a multi-hop path due to lack of path symmetry - i.e. strong mutipath or ground/ionospheric dispersion at one side and not the other.
    6. Other differences in equipment quality, installation quality and operator skill at each end

    And the list goes on.

    So is it REALLY that the local noise floor has increased, and THATs the primary cause of the RXing station seeming deaf? Because in this solar down cycle, we have a whole lot LESS propagated noise and QRM from all sources, and many previously serious noise sources, like broadband noise generated by millions of cars and trucks, has actually gotten better, with elimination of points and introduction of electronic ignition.

    With FT8 the adjacent/overlapping channel problem is very exaggerated, illustrating a major driver of TX/RX inequality. A QSO with a station having both a stong signal and SNR often goes bad for a period due to interference from a station that can be heard on the RX end, but not the TX end.

    Food for thought and comment.

    Brian - K6BRN
     
    W4NNF likes this.
  3. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Absolutely agree!
    It's tough when the problem is a solar AC line controller or HVAC system.
    Jen and I throw famous block parties so the neighbors are on first name terms. They're really fun and makes it easier to pursue problems when we have to.

    Right now, we're trying to get ConEd to replace the low voltage (240v) line around our block. The transformer is new and bigger. There are dozens of bad splices on the LV line around the block to our house. We see <103VAC on scorcher days. 12 letters from neighbors on the same block may get through.

    2 blocks away, this isn't a problem because a truck hit the power pole and ConEd had to replace the LV wiring and repair the drops to the houses. Those neighbors have good power even when it's hot. We're still working this problem!
     
    Last edited: Sep 8, 2018
  4. K7MH

    K7MH Ham Member QRZ Page

    Or just pay attention to what you are doing!
     
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I'm surprised a transformer supplies houses all around a block. Usually they're "sized" to supply four residences per pole pig transformer. At least here they are, as well as anywhere else I've lived.
     
  6. WE6C

    WE6C Ham Member QRZ Page

    Piece of paper and a pencil! Duh!
     
  7. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    It's really bad in this 'hood!
    11 houses, all 3 family. One medium sized pig...
    That's why I had to install a couple 3kVa regulators. One for the shop and one for the studio, or the gear goes belly up.
    This block is old. We just had the gas mains changed and the crew was pulling rusted lumps of old valves out of the ground. It was really scary!
    They told me that the gas and electric was last done in the early 70's. The gas was overdue, and the electric is still overdue.
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Eleven 3-family houses on one pole pig transformer is amazing.

    I'd imagine each residence is only good for 50A at 240V or something like that.

    We have 200A service here, single-family residences, and I've never seen one pig serve more than four homes. That "might be" (this is a fairly old neighborhood, 1956-57 vintage builds) because the homes originally came with electric cooktops and electric ovens, and central air conditioning which was pretty "new" at the time but very old-fashioned by today's standards. Most homes also had builder-provided swimming pools, which means electric motors for pumps that might run almost all the time. Today's HVAC units are far more efficient and also more powerful but probably draw less current. Mine was all replaced in 2000, so it's not new, but fairly modern.

    Our hot water heater is natural gas, and so is the pool heater so no burden on the lines. I doubt we could ever hit 200A with everything running at the same time, but we might hit 100A, especially on the holidays when we could have the cooktop and double oven (all electric) running at the same time as the A/C and the pool pumps.:p
     
  9. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    "Amazing" -ly bad... :p
    This neighborhood went together in the teens as a coal mining town that supplied NYC. There's a seam down at the bottom of the hill.

    Anyway, there's natural gas for cooking and I suspect that when the electric supply was redone around '72 that the engineers used a pretty low average load per house. The mains boxes in my 4 apartments are 60A each but the mains is fused at 150 amps. Fortunately, I live in all 4 apartments! My girls have something that not many children in NYC have... their own bedrooms.
    1 of those apartments is an electronics repair shop and another is a record cutting studio. That gear simply can not run unless the juice is even-Stephen or it will get unbelievably expensive when the power amps eat a cutterhead (like buying a decent car and rolling it off a cliff for fun).

    When it gets hot around here, the voltage sag makes it so that you run around the house turning off computers and other delicate equipment not on regulated power or they're gonna crash and possibly burn.

    The radio shack is on regulated power, of course. :D

    It's nice and cool today but when it warms up next week, I'll post an IR picture of the LV lines. I might even find the bad splices! :p
     
    Last edited: Sep 9, 2018
  10. K6BRN

    K6BRN XML Subscriber QRZ Page

    I live in Manhattan Beach, CA, whose homes and electrical grid were largely built in the 50's and 60's, same has the adjacent cities of Hermosa Beach and Redondo beach. The electrical gid consists of an East-West above ground HV transmission line network and a North-South underground network charged with inert gas.

    But since the 90's, standard home service has grown from under 100 Amps to 200 Amps and now some are 400 Amps (the biggest and more recent mini-mansions) as homes were rebuilt with the result that the grid would regularly overload and go down in all three beach cities.

    It was not unusal for half or more of a city to black out at once, with usually about at least one major event a month. SOP was for the electric company to bridge power over to another parallel (and overloaded) East-West or North-South HV line while they repaired the failed one. Wth the result that we had some REALLY spectacular and firey subsequent failures. It got so bad the we put in a backup generator, distributed surge protectors and UPSes all aroung the house, on key equipment. So my place just did not go down. It was even featured on one of the local news channels during one 24 hour event as an island of light in a sea of darkness.

    The beach cities banded together and sued SoCal Edison at one point, leading to representative Ted Liu stepping in to mediate events. The outcome was that Edison laid all new and heavier HV feeder lines throughout the neighborhood. But just when we thought the electrical system was good to go, the cross-bars and wooden poles began to fail under the weight of new wiring and we went through a scary period where 10+ KV lines were dropping either on or very close to the lines from the pole pigs going into homes. I had to stop and call 911 one day when I noticed a failed cross bar dropping a (13 KV?) line nearly on top of a 240 volt distribution line on Redondo Ave. The fire department cleared the block and brought in the electric company to fix the problem.

    Then that was fixed about five years ago, and we've been pretty good since.

    Brian - K6BRN
     
    KD2ACO likes this.

Share This Page

ad: vanity