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Messages - redhat

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121
FM DX Loggings / Big FM DX opening today.
« on: July 25, 2021, 0015 UTC »
I heard several stations on the stock x-mobile radio, most in the 1200 mile range.  Not strong enough to pull in RDS, but enough program info to corroborate with the station websites.

+-RH

122
Equipment / Re: Construction of Shortwave beacon
« on: July 20, 2021, 1712 UTC »
If cooling is a concern, construct the enclosure out of a diecast aluminum box.  That will be more than adequate for this power level.

+-RH

124
Doesn't surprise me.  I've seen more than a few questionable designs come out of icom over the last few decades.  From filter boards that zorch and smoke, to things like this...no thanks.

+-RH

125
I guess I should have read this document Sooner.

Some thoughts;

I have lost a handful of SiC devices over the last few years while building my transmitter, and usually they failed because of my assumptions in design leading to a few deficiencies.  One thing I did find during my research is that most of the failures occurred during drive loss events.  This seems to be evident in the transient nature of the waveforms you observed.  Most DDS devices produce a DC output when not programmed, and this is specified in the Analog Devices datasheet for the AD9850.  I think Stretchy was using a 9800 series DDS in his devices, mainly for cost reasons.  Until the program is loaded into the DDS, it will latch the output of the PA on, causing an overcurrent failure of the transistor.  My solution was to add a drive loss protection circuit, and I have not lost another device since.

The later versions of his transmitters I noted the elimination of the modulation transmitter, and instead feeding the PA directly from the modulator.  This may well have solved the problem, as the modulator has overcurrent sensing and protection built in.

+-RH

126
Huh? / Re: Windows 11? Why???
« on: July 07, 2021, 1505 UTC »
I gave up on MS years ago.  I've been running Linux in some flavor for over a decade.  Its free, and has it quirks, but does what I need.  Did I mention its free?  ;D

+-RH

127
Propagation / Re: VHF Airplane Scatter
« on: June 09, 2021, 2244 UTC »
If you monitor empty FM channels (is there really such a thing anymore :P ) you will hear this quite a bit.

+-RH

128
You may hear more about this in the future.  I read recently that the commission is considering relaxing the rules on AM antenna efficiency in order to provide stations more latitude with regard to finding replacement tower facilities for stations displaced by urban sprawl and gentrification.  Usually you have to have a full proof done by measuring field strength at many points and requesting an operating variance, or something to that effect.

+-RH

129
Lots of luck enforcing any of this....

+-RH

130
Pretty good copy here of U2's "I Will Follow".  About S6 here on the MW vertical.
0229 New Order "Blue Monday"
0232 MRI "turn it up" ID, into what sounds like the Pretenders Talking Heads 'Take Me To The River'
0242 David Bowie 'China Girl'
0258 Depeche Mode 'Personal Jesus' No real change in signal over the last 45 minutes.
0300 MRI ID into Boy George? Culture Club "I'll Tumble 4 Ya'
0307 INXS 'Need You Tonight'  Seems a good night.  Got Cevapi off the grill, cold beer, and tunes on the radio :)
0313 Tears for Fears 'Mad World'
0323 The Psychodelic Furs 'Love My Way'
since we're doing 80's How about The Church 'Under The Milky Way?
0327 Peter Gabriel 'Sledgehammer'
0335 MRI Request ID. into The Church 'Under The Milky Way'!  Thanks bud :)
FWIW, frequency is dead on via the SDR tonight, as always 6865 KHz USB.
0340 MRI 'It Just Rocks' ID, into B52's 'Private Idaho', another one of my favorites!
0344 MRI phaser type ID into The Polecats 'Make a Circuit With Me'
0347 David Bowie 'Lets Dance' (Radio Edit) Another good one!

Thanks for the tunes!

+-RH

131
I believe that the Israelis had a "hardened" antenna  (if I recall correctly)  for AM broadcast. It consisted of  heavy steel I  beams welded in series  stood off on large insulators , very close to the ground (6' up ?) .There may have been protective earthen dikes around it as well.

I would wonder if you go to that length, whats to keep someone (with lots of money) from floating an entire building an using that as an antenna?  Maybe a watertower?

During WWII, many domestic AM's that were considered "essential" built fortifications around their tower bases to keep the enemy from shooting out the insulators and bringing the tower down.

+-RH

132
Some folks have had good luck with the D-Kaz on lower frequencies, especially medium wave.  Perhaps this could be scaled down slightly for 4 MHz?
http://durenberger.com/wp-content/uploads/2019/11/D-KAZ-COOKBOOK-Pt1.pdf

+-RH

133
Equipment / Re: MFJ-209C for medium wave tests?
« on: May 01, 2021, 1512 UTC »
I still have my RigExpert Zero, which I bought on your recommendation Chris.  I bought the 35 Zoom simply so I didn't have to keep dragging a laptop to the base of the antenna every time I was in the field setting up for a show ;D

+-RH

134
Equipment / Re: MFJ-209C for medium wave tests?
« on: May 01, 2021, 0123 UTC »
I never liked the MFJ analyzers; too easy to damage by inadvertent static, etc.  I bought a rigexpert AA-35 Zoom last year, couldn't be happier, and it goes down to 60 KHz.  And yes, I have used it on a psudo-part15 station.

+-RH

135
With the changing of the guard at the commission, this may have the desired effect.  It is rather satisfying to read such roasting in legalese ;D

Maybe all the racket on 43 meters will go away soon, just in time for the coming of the new cycle.

+-RH

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