Morse Below One Watt -

Started by RadioRay, February 09, 2014, 12:10:18 PM

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RadioRay

There are those who telly ou that you MUST run 100 Watts or more - a kilowatt being essential for any serious/reliable radio station.  Then there are those who focus on antennas , quiet receivers and filters. Gil and I were chattering away on the radio, him with his 12 Watts and me with my 50'ish, testing my home brew amp.  I live in a rural, very low electrical noise area, so I can hear almost anything on the air.  Just for fun, Gil dropped hi power to 100 milliWatts (1/10th of a Watt). He was very weak but readable at 1/10th of a Watt! He increased to half Watt and it was quite usable.  At three Watts he was beginning to be considered strong and by 12 Watts he was s-8.  Wes Heywood, probably 'The Father' of wilderness QRP operations, did a lot of research and with the batteries of his day, 1/2 Watt - usually on 40 meter CW - was found to be quite reliable, assuming proper time of day, per distance was planned in advance.

This is no magic act.  Assuming an efficient antenna , it's just a matter of right time of day and band. Gil has a 1/2 wave , end fed wire and I have an 80 meter dipole - at 90 feet.  Of course, last year I was using a wire only 20 feet to the top, so for "only" a little over 800 miles, it's not that big of a deal.

The Point?  Cw is extremely efficient; the math shows a system gain for CW over voice of roughly 13-18 dB, depending upon who's numbers you are using. So, for the same reliability of transfer of intelligence you would need either 100 Watts SSB voice or 5 Watts CW.  I know personally which is easier to recharge in the field.  I have worked low power voice before, with my old PRC-74B manpack and with the little FT-817 and long ago with the 2 Watt Argonaut 505. It can be done.  However, I would STRONGLY encourage prepper hams to take-up CW.  You will not be disappointed.



73 de RadioRay ..._  ._

"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry

gil

That was a fun QSO Ray, thanks again. It isn't the first time we try 100mW either, and it works regularly. The Rock-Mite is a perfect example of a tiny rig that can be heard thousands of miles away on 500mW. The record for a RM QSO is New Zealand from the United States. It doesn't get much further. I have reached Estonia on 1.3W. Russia regularly on 5W.

I think what people lack is not power but patience. Obviously it isn't going to work every time! Usually, when there aren't a bunch of people calling on the same frequency and the band is open, I am heard by anyone I can hear. My antenna is nothing spectacular, a 40ft. end-fed which starts about 10ft from the ground. I use 50ft of RG-178 thin coax.. But... My SWR is 1:1, no tuner. And of course it's CW. Forget SSB at those power levels...

The main issue for prepping is recharging batteries. I don't mean with your gas powered generator... I mean when there is no more gas and all you have might be a small solar panel. Not to mention the weight... I believe, like all fistfights eventually end-up on the ground, most serious emergencies, soon or later, will leave you on foot...

Tune down to the CW portion of any band at the right time and you'll hear Morse code... There is no lack of contacts to be made. If I was in a real dire situation, I would call SOS in Morse before even thinking of SSB. I know I would have a much better chance of success with CW. Yes, it's archaic and a pain in the ass to learn, but it works! It is also a lot of fun and very rewarding when you start to hold conversations without writing stuff down.

If I could have only one radio, it would be something like a KX1 or my MTR. I love my KX3 too, but it "burns" 160mAh on receive instead of 35mAh for the MTR, about the same I assume for a KX1. My K1 used 50mAh. How significant is that? Well, the FT-817, great radio BTW, burns 450mAh I heard... Get an IC-7100, and that goes up to 1.5Ah if I remember well. I don't feel like hiking with a car battery... Eight AA cells will last for a couple weeks of daily operations, two skeds a day with a Rock-Mite, KX1 or MTR...

Simpler and smaller is better. Look at people who walk the Appalachian Trail... They shed every ounce they can from their pack.

Hams tell me "I'll be staying home and I have a generator and big solar panels..." You don't know if you'll be staying home... You might have to leave it for good for safety reasons, or simply leave it temporarily to resupply, etc. Imagine a radiation problem... Stay home and fry...
There are a lot of more important things you need for survival other than a radio, which is one more reason to have a small one handy. Sure, have your big rig, Yagi-Uda on a tower and digital this-and-that... No problem, we all love radio gear. Do have a small QRP rig however and learn CW. Because when it's time to bug out and you need to know what's going on or contact friends on the move, nothing beats it.

Gil.

cockpitbob

With my QRO rig in the shop I've been chasing some Dx with my QRP rig (TenTec R4020) and I'm stunned at what I can do with 4W.  I'm consistently hitting people 4,000 miles away in Europe.  I just finished a QSO with someone in the Czech Republic (3,900 miles).  He was way down in the noise for me and I was getting 50% copy with the QSB, but he was getting solid copy on my 4W.  Seeing his QRZ.com picture of him in a canoe with a mast antenna and solar panel makes me think he's a QRP guy too. 

KK0G

Quote from: cockpitbob on March 11, 2014, 10:54:23 PM
With my QRO rig in the shop I've been chasing some Dx with my QRP rig (TenTec R4020) and I'm stunned at what I can do with 4W.  I'm consistently hitting people 4,000 miles away in Europe.  I just finished a QSO with someone in the Czech Republic (3,900 miles).  He was way down in the noise for me and I was getting 50% copy with the QSB, but he was getting solid copy on my 4W.  Seeing his QRZ.com picture of him in a canoe with a mast antenna and solar panel makes me think he's a QRP guy too.


Yep, QRP clearly works and very well I might add. I sold my fire breathing, 100 Watt, TS-2000 to fund the purchase of my K2 with it's measly 12 Watts maximum PEP (which I keep set at about 5 watts) and I don't miss it one bit. Not once have I said "Gee, if I only had another 95 Watts I could have made that contact".
"Those who would give up essential liberty to purchase temporary safety, deserve neither liberty nor safety" - Benjamin Franklin

KK0G

gil

It is always a surprise to me when reducing power as an experiment, how low you can actually get and still be heard. When it goes through, it goes through... Then it's a matter of noise to signal ratio. The only times I am not heard is when other stations supplant me with more power or the band is not quite open. I think the "comfort" threshold is about 3W. 1W works of course, but multiple hops are harder. I think the 5W QRP definition, though I think "QRP" for me is not just about power level, is a good number and was chosen for practical reasons.

QRP for me also means light, as in "less weight to carry on a hike." "Less than 1W" = "Less than a pound?" "QRP" = "Less than 5Lbs?" It is an interesting comparison. The only thing that might change that relationship will be advances in battery technology. That is what will change our world, and not just for radio.

Gil.

KK0G

Quote from: gil on March 12, 2014, 10:41:05 AM
............The only thing that might change that relationship will be advances in battery technology. That is what will change our world, and not just for radio.

Gil.
If/when that happens I'll keep it at QRP levels and convert the extra power into longer duration.
"Those who would give up essential liberty to purchase temporary safety, deserve neither liberty nor safety" - Benjamin Franklin

KK0G

cockpitbob

OK, I'm all geeked-out and have to tell someone. 

I just worked RI1ANT with 3 Watts (low batteries).  Yes, that's Antarctica which is 10,700 miles from me.  That's 3,600 miles/watt.  It blows my mind what QRP CW will do.

Normally I don't care about wall paper, but this one is special to me.  If I can get him to QSL I think I'm actually going to bother to get one of those 1,000miles/watt certificates for this one.

gil


KK0G

Very cool! I don't blame you a bit for being geeked out, I would be too.
"Those who would give up essential liberty to purchase temporary safety, deserve neither liberty nor safety" - Benjamin Franklin

KK0G