Dan - KD7WRJ 🍀🌐📻

Radio is my interest since 1975. Ham Radio, SWL DX, MW DX. IRCA member. City planner by profession so there might be tweets about cities and planning.

[ALBUMISM @Albumism]

Happy 55th Anniversary to the Allman Brothers Band's ‘At Fillmore East’ originally released July 6, 1971 | Read our tribute by @TweetsLevine + listen to the album here: https://t.co/YEzo6Figgq

[ElectronicsNotes by Ian Poole @ElecNotes]

Understanding Tropospheric Enhanced Conditions: Lifts, Ducting, Tropo

Under certain conditions the radio propagation conditions provided by the troposphere are such that signals travel over much greater distances than normal.

This enhanced tropospheric refraction occurs when there is a significant increase above the normal value of the refractive index in the atmosphere.

This form of "lift" in conditions is less pronounced on the lower portions of the VHF spectrum, but is more apparent on some of the higher frequencies.

Under some conditions radio signals may be heard over distances of 1000 or more kilometres. This can give rise to significant levels of interference for broadcasters and two way radio communications services, etc for periods of time.

These extended distances result from much greater changes in the values of refractive index over the signal path.

This enables the signal to achieve a greater degree of bending and as a result follow the curvature of the Earth over greater distances.

There are several conditions that can give rise to enhanced tropospheric radio propagation ,i.e. lifts and ducts.

•Settled high pressure:   The classic weather formation that causes a lift in conditions is the presence of a high pressure area. The particular enhancements occur along the isobar pattern, i.e. along lines of the equal pressure. It has also been found that the best enhancements occur when the pressure is falling slightly.

•Fog:   When fog is present, especially during a period of high pressure, this can give rise to excellent enhanced propagation conditions. A temperature inversion can occur because there is the fog with clear sky above it. As a result of the sun reaching the top level of the fog, this will be heated and not the lower regions because they are shielded from the Sun's warming rays. Accordingly, this causes a temperature inversion which can enhance the radio propagation.

•Frosty mornings:   It sometimes occurs that frosty mornings can give rise to a degree of enhancement. The cold Earth takes some while to warm, but the air above the earth will tend to warm faster as the Sun's rays affect it more quickly. This effect is more of a winter one and it is not as pronounced as the enhancements cause by summer high pressure areas.

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

https://t.co/cl7IEORF5a

[Allan Weiner @AllanWBCQ]

Peaceful coexistence-that’s the goal. No more wars. No more fighting. It is so much easier to make peace than war. Honor the fallen with that notion. Enough conflict. Our goal now is to sustain and maintain our earth home and all its earthlings. Peace through Radio-WBCQ📻

[UW-Madison CIMSS @UWCIMSS]

Solar wind reaches Earth! Every North America satellite overpass captured the #AuroraBorealis last night. See all the images on the CIMSS Satellite Blog
https://t.co/GszwP3cqCS

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

Very cool history. @933KJR #radio #Seattle

[RossRadio @cqcqcqdx]

1925 Station KJR Seattle:
A new brick transmitter building and two self-supporting towers were constructed to support the characteristic flat-top “T” wire antenna of the era.  KJR operated from here until 1937, and it is now the location of St. Mark Catholic Church.

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

@Super70sSports Canned Heat on the road again.

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

https://t.co/Uaaj5KxCPx

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

Local radio at its best. This is how radio should work. #radio Al Wynn’s love of radio keeps The Dalles talking, together. ‘I’m in the goosebump business,’ he says https://t.co/Heph3n9SxF

[Dad Jokes @Dadsaysjokes]

If lightning strikes an orchestra, who's most likely to get hit?

The conductor.

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

@Chicago_History Garfield Ridge home of the goose

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

Interesting..https://t.co/vlxkIJ36wP

[Buitengebieden @buitengebieden]

Elephant says thank you after the herd crossed the road.. 😊

[soundStory 🎧 @soundstoryuk]

On this date in 1979
@TheB52s released
their debut album...
What are your favourite
tracks from this fabulous debut?

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

@PopShopRadio1 @MrsPopShopRadio 👍

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

@PopShopRadio1 Bem dito

[PopShopRadio @PopShopRadio1]

Hey Asia, the Pacific. Australia, New Zealand & west coast USA/ Canada. Pop Shop Radio will be coming your way with a special 250 kilowatt transmission from Woofferton 300° on 12005 kHz at 0500 UT on 13 May 2023. There will be a special QSL and eQSL and our new hologram sticker!

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

https://t.co/J8IhmCILEV

[Dan - KD7WRJ 🍀🌐📻 @kd7wrj]

Resting peace Gordon Lightfoot. The Wreck of the Edmund Fitzgerald by Gordon Lightfoot on Amazon Music
https://t.co/o9g21hZVU3