AmateurRadio.com

In an attempt to establish my ERP on 472kHz, I have crunched some numbers. I think it is error free, but no doubt someone will soon tell me!

With a 1:46 step up toroid, I am measuring the DC volts rectified across a 470 ohm secondary load resistor using a small 50uA meter in series with 240k ohms (120k twice) and a series silicon diode. This circuit is straight out of the “LF Today” book available from the RSGB bookshop.

DC current = 30uA
DC voltage across 470ohm secondary load  = 0.6 + (240 x 10E3 x 30 x 10E-6)  = 7.8V
DC voltage (rms) across 470 ohm = 7.8/1.414 = 5.52Vrms
I secondary = 5.52 * 10E3/470 = 11.7mA
I primary =  46 * Is = 46 * 11.7mA = 0.54A

Rrad = 160 * pi^^2 * Heff^^2/lambda^^2 = 160 * 3.14 * 3.14 * 2 *2/(630 * 630) =0.0159 ohms

P(erp) = I^^2 * R = 0.54* 0.54 * 0.0159 W = 4.6mW

My original guesstimate of 5mW ERP is not far out!

Clearly getting the antenna much higher would help enormously as ERP is proportional to Heff^^2. All one can really be sure of is the order of magnitude. I am running low milliwatts.

I like listening to the podcast of Ham Nation – which is both in video format and audio format – during my commute to the office.  Every other week they have a segment with user supplied videos.

I like listening to the podcast of Ham Nation – which is both in video format and audio format – during my commute to the office.  Every other week they have a segment with user supplied videos.

So long for now, sort of!

I have decided to ask Matt W1MST, the Editor at AmateurRadio.com to end the mirroring of this blog there.  I know this may appear to be kind of sudden, but actually, this has been a decision that I have been trying to discern since this past Easter.

The content of this blog is mostly about QRP and CW as you all know. So actually, I do cater to a rather small niche in the Amateur Radio world, and the things of which I write are not of interest to everyone – or even a large portion of everyone.  In addition, I have also been known to throw in random posts here and there that are of a religious or political nature, when the mood strikes me.  And I also regale my readers with my wacky sense of humor now and then.  They say that writers should write about what they know best, and that’s what I try to do – and at this stage of my life, I’m not going to change that.

That’s fine for people who actually come to w2lj.blogspot.com looking for that kind of thing.  They know what they’re in for when they walk through my door. But to be foisted upon folks coming to a “general interest” Amateur Radio site?  I think maybe not so much.

So, AmateurRadio.com readers, if you like my ramblings – please feel free to come to w2lj.blogspot.com at anytime, 24/7/365.  The door is always open and you’ll always be welcome. And per chance, should you not like what you see there – you’re always free to “change the channel”.

My thanks to Matt W1MST and AmateurRadio.com for the continued support over the past few years. Matt has been a most gracious host, ever since he asked my permission to mirror this blog over there. Certainly, the service he offers to the Amateur Radio community is a treasure. I will continue to keep the link to AmateurRadio.com active and open in my blog roll.  I hope you’ll feel free to bounce back and forth between us.

72 de Larry W2LJ
QRP – When you care to send the very least!

that I link to an article written for eHam, but here’s a really good one written by Ron KA3J:

http://www.eham.net/articles/32380

It regards Technicians (or any new Hams for that matter, CW and QRP – relevant topics for this blog!) And just to let you know how good it is, up to this point in time, Ron has not been heckled in the commbox!

72 de Larry W2LJ
QRP- When you care to send the very least!

Posted by Bobby AK4JA (who I’ve worked – fantastic op!) on QRP-L today. Provocative? Yes. Controversial? Yes. True? No, but I kinda like it anyway:

“QRP – a real man’s mode , not for sissies and certainly not for selfish, impatient , ego-maniacs – Man up, grow a set and go QRP if you dare!”

Not trying to start a QRO vs QRP war, but I enjoyed the humor. And it makes for a good battle cry. Definitely better than “Life is too short for $200 finals” or whatever some guys like to bandy about. And no, I won’t be changing my tag line.

Hey, Bobby! I think this would make a good T-shirt!  Something on the order of this:

Hee hee!  Is that a challenge, or what ?

72 de Larry W2LJ
QRP – When you care to send the very least!