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Messages - redhat

Pages: 1 2 [3] 4 5 6 7 8 9 10 11 ... 93
31
The RF Workbench / Re: dumb soldering question of the day
« on: June 23, 2020, 1857 UTC »
Over here, I've seen a mixed bag.  Development places working with R&D or grant money see more metcal (where cost IS no object).  The rework folks like myself seem to lean more toward Hakko, Weller, Ungar, and a lot of the cheap Chinese stuff.  I just got a Quick hot air rework station, mainly for doing SMT rework and small run proto's.

Above 50 MHz, SMT inductors can be had in values close enough to suit your needs, and the repeatability will be better.  Not sure I'd use torroids at 300 MHz...

+-RH

32
The RF Workbench / Re: dumb soldering question of the day
« on: June 23, 2020, 1626 UTC »
60-100W is really all you need.  I have an older Hakko 60W I bought on closeout from a large electronics retailer years ago and use it routinely for connector replacement on commercial equipment, and also in situations where I need more heat.  FWIW I used a metcal tweezer for many years, until the probes started leaking and blowing up components.  I then switched to a Hakko base and tweezer to compliment the rest of the bench setup.  Metcal was always way overpriced in my book, even used.

+-RH

33
Amateur Radio / Re: Anyone ready for Field Day 2020?
« on: June 23, 2020, 0404 UTC »
Might be a good time for pirates to wave the flag as well...

+-RH

34
The RF Workbench / Re: dumb soldering question of the day
« on: June 23, 2020, 0025 UTC »
Use a big (60W or better) iron.  Smaller pencil irons don't have enough heat to adequately solder larger metal parts.  Cheaper connectors with non-ptfe dielectric will melt if you use too much heat for too long.

The only stupid questions are the ones not asked :)

+-RH

35
See, if dispatch was in the clear (as it should be) this kind of racketeering wouldn't exist.

+-RH

36
I recall hearing the same thing.  A friend of mine had one of those receivers, but we had no signals to test it with, and my test generator was halfway across the country at the time.

+-RH

37
If you are in close proximity to any strong RF fields, the 'rusty bolt' syndrome can cause that, and aluminum is particularly bad about producing oxides.  I would try relocating your loop and see if any improvement is noted.

+-RH

38
General Radio Discussion / Re: CHAZ Free Radio Stations?
« on: June 20, 2020, 0723 UTC »
Oh wow!!!! Thanks for the reminder. I haven't corresponded with these two in years. Maybe, I should again. I even bought the DVD at the time and promoted the schytt out of their movie. I just can't believe that was just 15 years ago. (Here comes the Ben Stein WOW here.)

I bought their DVD too.  It took a lot of work to put together and glad they had the foresight to document all they did.

+-RH

39
General Radio Discussion / Re: CHAZ Free Radio Stations?
« on: June 18, 2020, 0646 UTC »
Seattle had a thriving free radio community back in the 90's.  There was a documentary about it called Pirate Radio USA, the link is here... https://youtu.be/hkQsHHwsj4M

+-RH

40
So where does one get the realistic BMI table?

+-RH

41
You're driving along enjoying the ride in your chick-magnet/road-sofa 89 K car, beige with white snowflake wheels and burgundy interior appointments, the am stereo emitting dulcet tones.

Suddenly bedlam! 

The phase changes and the sound starts rotating slowly one way around the cabin then the other as the signal undergoes fading!

And that, my friend, is part of it's charm...
https://youtu.be/lAMGmtzfwtc

+-RH

42
Equipment / Re: RF circuit help....
« on: June 12, 2020, 1734 UTC »
You can model a filter using various software as stretch mentioned.  I use the SVC program from tonne software.  Its a good freebie.  Using it you can play around with values to get the response you want, then build it :)

http://tonnesoftware.com/svcfilter.html

+-RH

43
Equipment / Re: MLA-30 Loop antenna
« on: June 09, 2020, 0130 UTC »
I bought one of these myself to see what all the fuss is about.  I'm considering getting a second one to keep in the 'go kit'.  I found its performance on medium wave to be acceptable, and the noise is no worse than my existing Chi-town special.  That being said, local noise around here is about s7 and the loop seems similar.  I may build a bias injector for it and see if any difference in performance is observed.  With it I did see WWV on 15, 20, and 25 MHz come in on it the other night, something I've never seen before here with the tune loop.

I will drag it with to a quiet location sometime and see how it behaves in a quiet environment.

+-RH

44
Many of the XTS series radios have what's known as tactical inhibit, a feature to destroy the encryption keys and other programmed data in the radio and prevent unwanted surveillance from a captured radio.  It can be defeated in the codeplug, i believe.

+-RH

45
Equipment / Re: Receiver protection from nearby xmtrs
« on: June 08, 2020, 2207 UTC »
The recommendation against using PIN diodes has to do with their nonlinear nature and tendency to produce IMD.  This is one reason they are usually not used in pre-selector circuits, as in the presence of high RF fields can produce IMD products....but then again so can conventional diodes.

+-RH

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