Tag Archives: Homebrew

Where have I been?

The life thing has been pretty disctracting from ham radio the past few weeks. I just returned from a week long business trip to the Philippines and then had a bunch of catch up to do. This week I started making Field Day and Portable operation preps. I took out all my battery packs and charged them with the solar panels. All are ready to go now.

I ordered a cool little gizmo for the FT-817ND. It is a 3D printed power connector that fits nicely on the back of the radio and converts the power inputs to Anderson powerpoles. I got mine from Ebay:

s-l500

Regarding Field Day, I am still thinking about a 20m beam.  I’ll be doing some modeling comparing the Buddistick, the 2 element vertical beam and a 2 element, inverted-V wire beam. I have already built two of these three and have good results on QRP.

I tried some operating today but so far conditions have been…well they have been pretty bad. SFI=68 and SSN=0 makes for some pretty bad propagation. Definitely need to up the antenna game.

Advertisements

QRP Tests of the 2el Vertical Beam

Rainy day today.

I had planned to take down the vertical beam antenna today and send up the end fed half wave to test for possible field day use. So instead I have left the 2el vertical beam in place and cranked down the power on the IC-7300 to 5W on SSB. I frankly was not expecting much as band conditions have been awful on 20m. I called CQ for a minute or two and a portable station in North Carolina picked me up. We had a short QSO and I received a 59 signal report. Called CQ again and picked up a station in Georgia. I was having more trouble receiving than he was in hearing me. QSB on 20m is pretty bad sometimes. Made one more call and was picked up by a station in KS who gave me a 57. Made  these three contacts over 10 minutes on 5W.

There is hope for Field Day this Year!

miniVNA and Choke Measurements

I recently bought a miniVNA Pro analyzer:

minivna_pro

This is a pretty cool little device that goes beyond just analyzing antennas. One of the first tasks I set this to was measuring some ferrite chokes for comparison. The miniVNA makes quick work of this in transmission mode and in saving the data in Excel format. Here are choking impedance plots for three ferrite based chokes:

chokes

In blue is 9 turns of RG-8X around two FT240-43 cores. This has the best choking performance. The orange plot is a 1:1 choke balun made from an ebay kit. The grey plot is an MFJ-915 line isolator.

2el Vertical Beam Antenna WSPR Results

I ran the 2el vertical beam antenna on 20m WSPR for most of the last week. This time I looked at the WSPR challenge data as compared to N5CEY’s station about 15 miles away. During the week we both made the WSPR challenge scoreboard. On some days I had a higher unique count while on others N5CEY did. The WSPR Challenge site provides a list of all the stations heard in a 24 hour period along with their counts. This can be downloaded and sorted to see which stations had the highest counts. The data for a specific station can then be downloaded over the time period. Here is the count comparison:

wspr challenge counts

Here is a plot of the reported SNR vs time to K8JBV in Ohio from both my station (red) and N5CEY (blue):

WSPR comp

This chart is fairly typical and shows that N5CEY has about a 6dB higher SNR at his station vs. mine. I did note at least two stations, one in Georgia and the other in Florida, that had SNR roughly equal at the two receiving stations. This correlates well with the direction I have the vertical beam pointed. Likewise stations on the backside of the beam have a  few dB more separation.

I am pretty happy with the performance of the vertical beam antenna overall. What I would like to do next is operate portable from a more rural location and measure and differences in SNR on WSPR.

Update on the 2el Vertical Beam

I guyed the antenna elements after finding it survived the night. here is a view of the antenna:

IMG_1505

I know it’s hard to view but the elements are there. 😉

This antenna is working very well and has scored the past couple of days into the top 25 in the 20m WSPR challenge.

 

Field Day and the 2el Vertical Beam

I came across an interesting read from Jim, N2GXJ entitled “Thinking about Field day Antennas“. This talks about Field Day scoring and how to improve your score. He points out that the key to Field Day comes down to the sheer number of QSO’s you make irregardless of where they are from. Jim starts by looking at poulation density from the US Census as an indicator of where ops will be located:

2018-04-10_9-42-47

This map tends to confirm my previous experience that the bulk of contacts are made up and down the east coast and in California. Last year I ended up running at 45W due to poor propagation and did notice many stations coming in from California. I made the mistake of not working more of them.

So from my QTH in South Texas I need to target the East and West coasts with daytime activity on 20m and 15m. The 2el vertical beam for 20m will definitely be a good choice for pointing to the east coast and should let me go back to QRP levels. I’ll try and test this out this coming Saturday if the weather holds (good to test the battery system while I am at it).

The 2el Vertical Beam Lives!

Made a run to Home Depot this morning and bought the PVC bits I needed to build the 2el vertical Beam I described in a previous post. The PVC is for the antenna mount to raise the feed point up to about 8 feet. I had some issues laying the elements out in the backyard as a tree was in the way. The two elements are 16 ft apart which is a bit further than the 13 feet modeling showed was optimum. I started by setting up the driven element. this went together very similar to the homebrew Buddistick with the exception that the fishing pole allows me to go full length. It tuned under 2:1 SWR across the whole 20m band. The reflector was even easier as it does not need to be tuned. I used one continuous piece of wire for the element and radial and keep the distance to the radial end at 14 feet. The beam is pointed in roughly a 45° bearing towards the northeast USA and Europe.

I should mentioned I did all this in a dead calm and in very muggy conditions outside today. I did not like the was the PVC was bending but rather than properly guy them I opted to try the antenna out a bit first…what could go wrong? I ran WSPR for about 2 hours with the following result:

2018-04-07

Note the high density of spots to the NE and the two spots to Europe. Pretty good for this time of day. Some SSB work towards the Mississippi QSO party yielded several “strong signal” QSO’s. I also made a QSO to Spain. After I closed that QSO, I switched to the S9V31 and noted a drop on the S meter from S4 to S1 when he was transmitting. Not sure what to make of that as 3 S units represents an 18dB change in signal strength. Perhaps the difference in pattern?

Did I mention what could go wrong? Let me first mention that PVC is like a wet noodle. The reflector was supported somewhat by some nearby tree branches but the driven element was not cooperating. I leaned a step ladder against it to provide a bit of support. Now remeber I did not guy it down as I was anxious to test it out. The weather shifted while I was gathering data. A cold front blew in and it started to rain lightly and the wind started gusting. The antenna has not failed but I don’t expect it to stay up through the night. The driven element is leaning over quite a bit in the breeze and I expect it to flop over at some point. The good news is this is hard to damage.

I’ll guy it up tomorrow for more extensive use. I think this is finally a winner in the gain department. Setup is fairly easy with the only thing I need to improe being how to get the feed point to 8 feet and still keep it portable.

Next Vertical Beam Experiments

My next experiment with a vertical beam antenna for 20m is coming up this weekend. My plan is to start with essentially a full length “Buddistick” on 20m using a fishing pole. I am going to plant 2 feet of a 5 foot 3/4″ PVC pipe as an initial support. On top of this will be another 5 foot 3/4″ PVC pipe joined with a pipe coupler. On top of this is a 3/4″ pipe coupler plus a 3/4″ to 1/2″ pipe adapter. A 12 inch length of 1/2″ PVC pipe will go on top of that and the telescopic fishing poles will slip on to this. Both the reflector and driven element will be mounted in this way. I may have to guy the mounts but short guys should work.

The driven element will have it’s feed point at 8 feet. The vertical element will be 16.5 feet long. The radial will be 17 feet long and slope down to an electric fence post at 4″ high. The reflector will be 13 feet away and be identical to the driven element except the vertical wire is 17 feet long followed by a 17 ft radial also mounted 4 feet high. Here is some EZNEC plots of this configuration:

2018-04-05_13-44-14

I am expecting that this configuration will be below 2:1 across the whole band, provide good low angle radiation, 3-4 dBi of forward gain and 10dB of Front to back. This should be easy to build and deploy

Weller 9400

I typically use a soldering station as most of my previous soldering needs were largely soldering PCB. Soldering RF connectors and the like is quite another story. I invested in a Weller 9400 soldering gun this past weekend:

weller-soldering-irons-9400pks-64_1000

Wish I had gotten one sooner. It heats up in about 10 seconds and makes short work of soldering PL-239 connectors onto coax. It is very convenient to just plug in and use.

 

2018 ARRL DX SSB Contest

Worked the ARRL DX SSB contest this weekend and managed to get 100 contacts over the course of the past 48 hours. I did not operate to aggressively but did operate with spotting assistance. I worked 46 countries on 40m, 20m, 15m and 10m. 34% were in North America, 30% in South America, 16% in Europe, 7.5% in Asia and 10.8% in Oceania. No contacts in Africa this year. None of the worked countries were counted as new ones. All in all not bad and a lot of fun considering the band conditions were pretty bad (SSN=0 SFI=67). North America was dominated by 20m, South America with 15m, Europe on 40m, Asia split evenly on 40m and 20m and Oceania also split between 20 & 15m. All in all 20m was the more difficult band to work with many really weak signals heard here at the QTH. 40m comes alive in the early evening into Europe and Japan in the early morning. 15m had less overall activity but had many strong signals from central and South America. My score works out to 22,572 with 100 QSO’s. The DX stations responded with power of 1000W about 90% of the time with the lowest power as 100W. Good test of the vertical 1/4 wave antennas!