Posts Tagged ‘AlexLoop’
Portable QRP = planning and adaptability
| Last years shot of my planned location for today |
| New setup in town |
| All packed up. |
| KX3 charging |
Alexloop vs Attic dipole
| Setup for test. (Laptop running Ubuntu update) |
A-5
K3
SFI 157
SN 173
Below is the results of the test.....not so well it would seem the Alexloop netted zero and the dipole only one. So is seems for a more acurate comparison better conditions are needed.
Alexloop on the deck calling CQ
| RBN spots (click to enlarge) |
A nice way to rest a sore back.
| Relaxing on the deck. |
Some things I tried with the Alexloop
1. I emailed Alex regarding his opinion about adding some extra coax so I did not have to be that close to the loop. He (as always) emailed me back within 10 minutes explaining there should be no problem doing this. At first I did try 12 ft of RG 213 and found I could not get a decent SWR. I then tried a 6ft piece
and all was well. This would allow me to sit at the patio table and not have the loop under the patio umbrella.
2. When tuning the loop if I was in front of the loop while adjusting it's capacitor I found I could get a 1.2.1 match on 20m..but..as soon as I moved my hand away from the loop the SWR rose to 2.1.1. I found by adjusting the loop from the back of the antenna the SWR was not affected.
| New loop to tripod adapter |
3. In the past I was using plastic zip wraps to attach the antenna to the tripod. I made and wanted to try a new antenna to tripod holder made of plastic pipe and heat shrink. It turned out to work just fine and will allow me to set the antenna up much faster in the field.
I called CQ on 14.060 for about a 1/2 hour and was not spotted on the Reverse beacon network. This does not concern me as conditions were not that great. It was not my plan to really make any contacts but the see how the loop fit on the deck. Also how the new adapter I made fit both tripod and Alexloop. Regarding the Reverse beacon network not sure if it is up and running properly today. I tried to refresh the spots and it seem to get stuck trying to refresh.
My Elecraft KX3 has a ping??
This afternoon I was planning on setting up the Alexloop into the living room and try some operating with the KX3. I was wanting to see how the loop worked in the living room. I was going to bring it on the deck but there was the threat of rain. Out of the blue when I was on 15m in CW mode whenever I keyed a letter and then released the key I would hear a very loud "ping" in the headphones. This only happened on 17m, 10m and 15m. I tried changing the headphones, using a dummy load and reducing the power to 0 but there was always a ping noise heard in my ear? I am not sure if I inadvertently changed a menu option that is causing this. This brought the living room KX3 operations to an abrupt end and off to the internet to see what was going on with the rig. I have posted the question on the Elecraft reflector as well as here on the blog.
Problem has just been solved seems if I have the rig on dual RX and VFO A and B are very close to each other I am picking up "me" on VFO B. Which makes sense and when in dual mod the head phones are split with VFO A in one ear and VFO B in the other. This would explain why the ping was only heard in one ear!
Problem has just been solved seems if I have the rig on dual RX and VFO A and B are very close to each other I am picking up "me" on VFO B. Which makes sense and when in dual mod the head phones are split with VFO A in one ear and VFO B in the other. This would explain why the ping was only heard in one ear!
The bandwidth on the Alexloop.
The next step in my Alexloop tests is the bandwidth in which the loop has. Again the antenna is mounted in a bedroom/office on the second floor of the house so that may have some affect on the SWR. I do plan on getting the loop in the out doors were the ceiling, walls and surrounding furniture do not have an affect on the loop. Below is the bandwidth results.
28.004 (SWR at 2.2) to 28.060 (SWR at 2.1) around 60 Khz of bandwidth.
21.020 (SWR at 2.0) to 21.070 (SWR at 1.7) around 50Khz of bandwidth
14.000 (SWR at 2.1) to 14.035 (SWR at 1.9) around 35Khz of bandwidth
10.110 (SWR at 1.8) to 10.125 (SWR at 1.9) around 15Khz of bandwidth
7.005 (SWR at 2.5) to 7.015 (SWR at 2.6) around 10Khz of bandwidth
I did however use the ATU on the KX3 and the SWR was flat when used on all bands so if I want I can use the tuner and increase the bandwidth of the antenna. I do know that my attic dipole on 10Mhz the SWR is about 9.1 to 1 and the tuner will flatten that out and I have made lots of milli watt contacts all over the world. So the next step is to get this antenna out doors and give it a whirl out there and see how it does.
28.004 (SWR at 2.2) to 28.060 (SWR at 2.1) around 60 Khz of bandwidth.
21.020 (SWR at 2.0) to 21.070 (SWR at 1.7) around 50Khz of bandwidth
14.000 (SWR at 2.1) to 14.035 (SWR at 1.9) around 35Khz of bandwidth
10.110 (SWR at 1.8) to 10.125 (SWR at 1.9) around 15Khz of bandwidth
7.005 (SWR at 2.5) to 7.015 (SWR at 2.6) around 10Khz of bandwidth
I did however use the ATU on the KX3 and the SWR was flat when used on all bands so if I want I can use the tuner and increase the bandwidth of the antenna. I do know that my attic dipole on 10Mhz the SWR is about 9.1 to 1 and the tuner will flatten that out and I have made lots of milli watt contacts all over the world. So the next step is to get this antenna out doors and give it a whirl out there and see how it does.
The Alexloop vs my attic dipole
| The new Alexloop antenna |
| A quality case |
So lets get to the nuts and bolts.....how does it work....sure anyone can say anything about their antenna but the proof is in the radio waves!!
| Antenna location..cat standing guard |
I wanted to do a comparison between my attic dipole which is the Alpha Delta DX-EE up about 30 feet in the attic and the Alexloop set up in my XYL's office just opposite my radio room. Let me state that this is not a comparison to see which antenna preforms better as that is not a fair comparison....but I wanted to see how well the loop did compared to my attic dipole. The Alexloop was mounted on a tripod....well ty-wrapped to it as the the Alexloop would not fit over the tripod center pole section. This is something I will have to work out later. Each of these antennas have their disadvantages....the dipole is in the attic, this means a wooden roof above, rafters all over and insulation below. The Alexloop is in a second floor room, it's a small loop antenna and very close to the ceiling. So really both antenna are far from ideal when it comes to location.
| Temp tripod mount |
My overall impressions of the Alexloop are as follows:
1. Shipping was fantastic, this antenna got here from South America faster than products I have ordered from the U.S.
2. The support is great, I had a question about the loop when it arrived and it was answered within 30 minutes!!!!
3. This unit is quality quality quality from the carry case to antenna!!
4. The tuning was a cinch, turn for peak noise and then transmit and tune for lowest SWR....takes about 20 seconds!
| 14.060, 7.032 Alexloop |
6. Antenna foot print is very low profile and can be used vertical or horizontal.
7. The SWR on 20m and 40m (only bands used so far) was 1.4 at 14.060 and 1.7 at 7.032.
The bottom line is I am very very impressed with this antenna and I will be taking it to the field and updating the blog on how it does. Up to this point would I recommend this antenna.......dam right I would it's support is excellent, quality of the product is way above par and so far the results have been very impressive.













