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Author Topic: QRP Works!  (Read 9905 times)

vwflyer

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QRP Works!
« on: May 19, 2015, 11:23:46 PM »
At least it did last weekend. On Saturday I got out my new MTR to try out the linked EFHW I just built for it. I also took the opportunity to save a CQ to the radio's keyer memory. I was experimenting with using the beacon mode where it would continue to send CQ until I stopped it but I was having trouble testing it because someone would come back to me at the end of the first CQ every time I tried it. I almost never get that kind of success on my QRO rig and permanent dipole. I don't know if it was luck or good propagation conditions or the fact that the memory keyer has a better fist than I do so people are more willing to answer (my QRO rig doesn't have a memory keyer). Whatever the reason, it has made me a belever in portable QRP. It gives me some hope that I'll actually successfully activate some summits this summer. I just hope that it doesn't work too well and I wind up having to deal with a pileup. I'm still green when it comes to morse code so I don't know if I could handle multiple summit chaser call signs coming at me at all at once.

gil

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Re: QRP Works!
« Reply #1 on: May 20, 2015, 12:39:56 AM »
FB! I think people don't give the end-fed half-wave the credit it deserves. It's a full length vertical "dipole" with a low take-off angle. What better antenna for DX, really? Not only that but you can still string it horizontally for NVIS on 40/80m.

Of course the MTR is awesome!

Gil.

cockpitbob

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Re: QRP Works!
« Reply #2 on: May 20, 2015, 09:11:10 AM »
I've told this a few times here, but I'll tell it again.  I was playing with my first QRP rig, a Ten-Tec R4020 (40/20meters) using my EFHW antenna and heard a Russian station calling CQ.  I replied and we just did the usual wham, bam, 599, thankyou Mam.  I went to look him up and he was at Russia's Mirny science station in Antarctica 10,700 miles away.  I was transmitting 3W.  Yeah, QRP CW is awesome.

madball13

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Re: QRP Works!
« Reply #3 on: May 20, 2015, 09:59:27 AM »
I've told this a few times here, but I'll tell it again.  I was playing with my first QRP rig, a Ten-Tec R4020 (40/20meters) using my EFHW antenna and heard a Russian station calling CQ.  I replied and we just did the usual wham, bam, 599, thankyou Mam.  I went to look him up and he was at Russia's Mirny science station in Antarctica 10,700 miles away.  I was transmitting 3W.  Yeah, QRP CW is awesome.

I can't wait!

gil

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Re: QRP Works!
« Reply #4 on: May 20, 2015, 12:24:21 PM »
Quote
I was transmitting 3W.  Yeah, QRP CW is awesome.

Yep, I once got Estonia on 1.3W, 5200 miles, using a PAR end-fed.

You have to be patient with QRP for long distances, but 5000 miles is a routine event for me on 5W. I don't really try Russian stations anymore, it's too easy :o

Gil.

KK0G

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Re: QRP Works!
« Reply #5 on: May 20, 2015, 12:55:57 PM »


........ I don't really try Russian stations anymore, it's too easy :o

Gil.

Come try that in here in the Midwest, not so easy.


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KK0G

vwflyer

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Re: QRP Works!
« Reply #6 on: June 11, 2015, 12:45:11 AM »
Well, I was getting a bit discouraged. I wasn't sure if there was something wrong with my antenna setup or what. For some reason I haven't been able to get the LED very dim on the SOTA tuner lately where before I could get it to go all the way out with the same wire. Also, the last three times I tried to make a contact resulted in no contacts or just one contact. Well, I've made it to Washington state now and am ready to activate some SOTA peaks. I figured I'd give it a try even though I hadn't had much luck with my little MTR and SOTA tuner lately. I went up my first hill today and after spotting myself on the sotawatch website I had a pileup in about two minutes. I worked eleven stations in about a half hour. I only did 20 meters for lack of time but I will try 30 and 40 next time as well. That should bring in people from other regions for even more QSOs. Still couldn't get much dimming action on the SOTA tuner so mostly tuned for max noise. Still, most people gave me a 559 or better though I did get a couple of 339s. I like that about SOTA, I didn't get one 599 report.

gil

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Re: QRP Works!
« Reply #7 on: June 11, 2015, 02:00:33 AM »
Excellent!

The SOTA tuner, and others using the same SWR indicator are very sensitive. As long as you see a little dimming your SWR is probably under 1.5. The LED is full brightness at 2.0 for sure. Did you use a counterpoise with the SOTA tuner as indicated on the label? The SOTA tuner is more of an off-center fed dipole tuner... I never use mine because I have other tuners, but it certainly works really well.

There is a big difference between being on a peak in the open and being in town. Here at my house in town I have trees all around, very bad for getting my signal out. When I go camping it's like having a 100W amp! Not to mention much less noise.

When I call CQ on 5W I rarely get an answer... On the other hand, when I reply to calls, even thousands of miles away, I usually get an answer... I don't know why that is... Any idea?


cockpitbob

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Re: QRP Works!
« Reply #8 on: June 11, 2015, 09:25:34 AM »
Regarding getting the light to dim more, are you sure your wire is the right length?  The equation of 468/MHz works well with uninsulated wire but I find I need to cut things about 5% shorter with insulated wire because the insulation's dielectric slows the wave speed a bit.

Knowing if the wire is 1/2wave on the desired frequency is hard with the SOTA tuner.  You have 2 resonances to tune.  The wire needs to resonate at your frequency AND the SOTA tuner is a resonant L-C that also needs to be tuned to resonate at your frequency.  If the wire is too long and resonates at 13.8MHz for example, you'll never get a dark LED at 14.05MHz.

Mostly I use a home-brew version of the LNR Precision coupler.  It's a wide-band transformer with no resonances or adjustments, so when I trim my wire I only have the wire's resonance to worry about.
If you think the wire might be a bit off, there's a method for finding just its resonance.  Set the radio at the bottom of the band (14.025MHz if you're a General), tune the SOTA tuner for dim, then increase the frequency 50Hz and re-tune the SOTA tuner for dim and keep working up in frequency in 50Hz steps.  Where the wire is resonating you'll get the dimmest possible LED.  If it just keeps getting brighter as you go up in frequency the wire is probably too long.


 

gil

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Re: QRP Works!
« Reply #9 on: June 11, 2015, 01:38:26 PM »
Good point Bob.

What I would also do is tune the tuner for the dimmest point at your desired center frequency, then go to the end of the longest wire and roll is on a pencil until the LED dims further.. You'll need someone to watch the LED and key the rig of course.. Then I'd do the same with the counterpoise, though that is less critical..

Gil.

vwflyer

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Re: QRP Works!
« Reply #10 on: June 12, 2015, 11:53:51 AM »
Quote
When I call CQ on 5W I rarely get an answer... On the other hand, when I reply to calls, even thousands of miles away, I usually get an answer... I don't know why that is... Any idea?

My guess is that when you are sending a CQ they feel no obligation to work at coping you and answer but when you answer their's they feel obligated to acknowledge your reply even if you are not an armchair copy.

Thanks Bob and Gil for the tuning ideas. I will try them out. It just seems weird to me that the same wire for radiator and counterpoise has given me lights out on the tuner in the past. I use the lengths recommended by the sota tuner chart for both the radiator and counterpoise. I've also used a 6 foot counterpoise and was able to get the light out in the past. I'm not sure why the same wires that worked for me in the past are not working now. I think that location of wire ends relative to the ground and other object might effect this. I may do more experimenting with lowering and raising the two ends of the wire when I have it in the inverted V config and just raising and lowering the sota tuner when I'm using it as a 20 meter sloper. It seems to me like I was having more luck getting the light to dim when I would place the tuner nearer the ground. Of course, in Mexico the ground is much dryer than it is here in Washington.

I might activate another summit this afternoon or tomorrow morning. I think I will do one that I can drive most of the way up. The last one I hiked from the bottom of and I learned just how out of shape I am.

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Re: QRP Works!
« Reply #10 on: June 12, 2015, 11:53:51 AM »