# The WORKBENCH

#382

ubuntu update to 17.10 went completely wrong

well… the RAK 8 dbm is definitely not a magic stick, just comparing otaa/abp joining with the A&C 3 dbi
have to reinstall RF explorer software on my laptop to test swr ect.

#383

Oh yeah… that were the days

#384

and those days were so fun …
assembly coding, learn hex and binary

#385

did you receive your RAK antenna aka ‘magic stick’ ? @Charles
I am curious if you also didn’t get antenna mounting material

#386

not yes they are stuck waiting the end of chinese new year to be posted

(LoRaTracker) #387

dBm is an absolute power measurement, as in 10dBm = 10mW

dBi is a relative measurement, as in the antenna has a gain of 10dBi over an isotrophic radiator (one that radiates equal power in all directions).

An 8dBm antenna makes no sense, suggesting that maybe the figure was invented by someone who does not know what they are selling.

#388

dBm is a log ratio of signal gain or loss.
See for a longer explaination:

(LoRaTracker) #389

dBm is a log ratio of signal gain or loss.
See for a longer explanation

I know what dBm is used for, but my statement was correct, to quote Wikipedia;

"dBm (sometimes dBmW or decibel-milliwatts) is an abbreviation for the power ratio in decibels (dB) of the measured power referenced to one milliwatt (mW). It is used in radio, microwave and fiber-optical communication networks as a convenient measure of absolute power because of its capability to express both very large and very small values in a short form.

(Remko) #390

Not entirely. It also simplifies power calculations.

#391

Maybe RAK’s ‘magic’ stands for:
‘how are you going to mount this thing without mounting materials?, it must be magic.

#392

tnx for the info

So (without ‘real’ measurements yet) my observation that the RAK antenna performs equal or a bit less then 3 dBI I have could be right ?

(LoRaTracker) #393

Well even if the 8dBM was meant to be 8dBi, you might expect such an antenna to be bigger (longer) than one that is 3dBi. I am very sceptical as to the claims made by some who sell antennas.

Its actually not that difficult to measure the real world relative gain just use a 1/4 wave vertical with radials as a reference.

#395

#396

Nice. Looks interesting. I hope everything will fit, because it has different measures.
(Wouldn’t it be easier to use his custom made PCB?)

#397

lots of 'old ESP12’s in stock … plenty of space

(Danny Engelman) #398

No… ‘The’ days started half a decade before Commodore:
I still have a TRS-80 somewhere in the basement
(and a VIC-20)

#399

my most funny one is called ‘banana’ … a chinese apple 2 clone , still have it somewhere

this was my first ‘real’ computer (I was 15/16 y/o) - a commodore CBM 3032
had to work really hard before I could buy it
sold it just a few years ago in working condition to a collector

(LoRaTracker) #400

Do you have one of these;

Its in my attic somewhere.

Plus an Apple II, UK101, Tangerine Microtan 65, BBC Micro (used to make them) and an assortment of IBM AT and XT motherboards (used to fix them).

I recall that the Apple II cost me circa £1299 with disc drive in 1979, the equivalent of £7000ish in todays money.

(Jeff Uk) #401

The NSc SCaMP wow I forgot that one! I designed and built my own computer based around that and set on Veroboard entered it for the Young Engineer for Britain comp (yes I was young once ) whilst an undergraduate apprentice for a Mil Aero player. Even fabricated my own case for it - approx 4u high - using apprentice training school facilities - in military green power coated aluminum. Could programme in Hex Assembly using 2 x hex key pads (Add & Data) and associated dual (quad?) 7 segment led displays and some switches controlling load/run etc on front panel…or could take the ‘easy’ route using an in built version of TinyBASIC (2kB?) that was accessed over serial port connected to a current loop driving a telex type TTY keyboard/printer as user interface…simple hello world type progs worked well but never quite got a moon lander game to run quite right (just added more craters most runs! Teh Heh). It was quite a hack. I think it was around then I decided I wasn’t a ‘Softie’ and should stick to hw & semi’s…now here I am worry about how to programme and load LoRa nodes…ah well what goes around comes around…

#402