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21
Antennas / Re: Random wire antennas and tuners
« Last post by gil on June 14, 2018, 06:56:12 AM »
Try a clamp-on toroid choke and slide it on the coax for best SWR...

Gil.
22
Antennas / Re: Random wire antennas and tuners
« Last post by CPR on June 14, 2018, 06:26:40 AM »
You might want to try a different wire length for 40 and 80m. Also, try a different coax length and maybe a counterpoise. Random wires can be a pain, but they do allow multiple bands...

Gil.

I took the wire length from here: http://udel.edu/~mm/ham/randomWire/ (84ft wire with 17ft counterpoise). I got a counterpoise, but I am uncertain how to lay it out. I tried directly beneath the radiating wire when horizontally for NVIS, and I tried 90 degrees. But if the unun is in the air several meters, then most of the counterpoise wire is hanging down. ???
I used 5m coax. With 10m coax I got worse SWR readings. I don't know, is my coax maybe acting as an antenna to? Do I need a choke?
23
Antennas / Re: Random wire antennas and tuners
« Last post by gil on June 14, 2018, 06:14:57 AM »
You might want to try a different wire length for 40 and 80m. Also, try a different coax length and maybe a counterpoise. Random wires can be a pain, but they do allow multiple bands...

Gil.
24
Antennas / Re: Random wire antennas and tuners
« Last post by CPR on June 14, 2018, 06:07:52 AM »
I was out yesterday to test out the 9:1 with a random wire.
I can say, it is really quiet! At home I got QRM on s7, out there it was 0. Very, very quiet antenna! I also built a RF choke balun / air choke but I see no difference. A thunderstorm kicked in and I had to sit it out, cooked some meal in the meantime.
Anyway, I had a QSO with Moscow, that is 1850km away on 5W! And I can't tune it to 40 and 80 meters. I dont know why. Unfortunately my antenna analyzer was switched on all the time and drained the battery so I could not see the SWR on the randomwire Unun without the tuner. I added a longer tentpeg to the counterpoise as some kind of a ground but did not notice any improvement at all.
Next time I have to take the antenna analyzer with me to get sure. Anyway, I am pretty pleased with the random wire. It is easy to set up! I set it up horizontally to the ground, hoping, I could get some local contacts but I did not. Weird. I made a video about it.

https://www.youtube.com/watch?v=EV4glRZnELQ
25
Digital Modes / I tried FT8 last night!
« Last post by gil on June 14, 2018, 05:01:34 AM »
Sure won't do that again! :o

I knew it probably wasn't for me, but with all the hooplah, I had to give it a try, at least to know what I'm talking about if ever that conversation pops up in good company... I even made one contact. For me, it's like watching paint dry, utterly useless and uninteresting. I'm not bashing FT8 users or even FT8 here, but it just isn't for me, by a very long shot.

I used the same software however for WSPR, to see my antenna radiation pattern, very useful, got Venezuela on 40m 2W. Of course with WSPR you don't put anything in your log, but I couldn't care less about my log. I actually only input contacts maybe half the time, when I don't lose my notes, forget to write the date or call signs...

Radio for me is about human interaction if only to ask what antenna someone is using... A few words about the weather, even a simple FB, exchanged between two people, make my day.

Gil.
26
New To Radio / Re: New to HAM Community What is a good beginner rig?
« Last post by gil on June 14, 2018, 04:20:16 AM »
Sure, and you're doing great, so keep at it :-)

Gil.
27
New To Radio / Re: New to HAM Community What is a good beginner rig?
« Last post by CPR on June 14, 2018, 03:29:12 AM »
I know that CW is the best energy efficient method, but for a beginner I think SSB is a good start. I had a QSO with Moscow yesterday (1800km) on 5W SSB. Getting through pileups with a  QRP rig on SSB is very frustrating. But for me it's fun. Sooner or later I will get a 50W amp for sure.
But for beginners, I don't know if CW will be learned right at the start - I guess not.
28
New To Radio / Re: New to HAM Community What is a good beginner rig?
« Last post by gil on June 13, 2018, 06:12:52 AM »
Current draw is my pet peeve, so I'll add my $0.2 here... I really like the 817 too. 350mA isn't too bad; more than my KX2 or my RT-320, 175mA, but you can run an 817 for some time on reasonably sized batteries. Now take a Weber MTR4b, 20mA current draw! That means it will last 17 times longer than the 817 with the same battery, 50 times longer than a QRO rig. A battery that will power your big Icom or whatever for a couple hours will run the MTR non-stop for four days ! Let's that sink in for a moment... Yes, a small CW rig beats everything else.

Gil.
29
New To Radio / Re: New to HAM Community What is a good beginner rig?
« Last post by vwflyer on June 12, 2018, 11:04:59 PM »
Quote
The main advantage of qrp rigs is power drain. Qro rigs in qrp mode drain much more power than pure qrp rigs.

That's true. The 817 realistically draws what on receive, 350ma? Most QRO rigs can be made to draw something in the area of 1 amp if you turn down or off some settings. That's a realistic difference of a solid 500-700ma. Figure 600ma at 12.5 volts and we have 7.5 watts of power savings.

Of course the oft-quoted downside of QRP is it's less reliable ability to be heard. To help overcome this handicap, more efficient modes are used, i.e. CW and digital. The problem with CW is that it kind of requires that the operator learn it. The problem with digital is that it requires a separate computing device, which also draws juice, cutting into your power savings. A laptop is the most convenient platform for working digital but it's also the most power hungry. A smartphone is the least power hungry but kind of inconvenient with it's small interface. A tablet is often chosen as a happy medium. The screen of a tablet is the most power hungry part of it, and unfortunately, outdoor/portable use generally means that the screen brightness has to be turned up to see it in the daylight. An iPad Mini at full screen brightness has been measured to draw about 4.5 watts. This makes your power savings only about 3 watts over a QRO rig that doesn't use the iPad. 

So at a battery voltage of about 12.5 volts that comes to an additional 240ma draw on the battery that a QRO rig has over a QRP rig coupled with an iPad Mini. That means that if you want to be able to have 8 hours of receive/monitor time, you'd need a battery that was about 2ah bigger to do so with a QRO rig vs a QRP rig/iPad combo. The difference in size and weight between a 7ah battery and a 9ah battery is pretty minimal and may well be worth it to have the option of going QRO when you need it.

I'm not saying that the 817 is a bad choice. I would certainly own one if I could convince myself that I needed one, and I almost have on a few occasions. It does everything under the sun and coupled with a small power amp can certainly take the place of a shack rig. It's an all around work horse. But to make it a reliable mode of communications, one has to either learn CW or concede that it's power savings over a QRO rig are going to be modest.
30
New To Radio / Re: New to HAM Community What is a good beginner rig?
« Last post by CPR on June 12, 2018, 02:06:23 PM »
The main advantage of qrp rigs is power drain. Qro rigs in qrp mode drain much more power than pure qrp rigs.

Via TapaTalk
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