Category Archives: HF Portable

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!

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).

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

Inadvertently Stress Testing a Homebrew Buddistick

I took out my homebrew Buddistick over the weekend to test its performance versus the full size verticals I have been playing with. I haven’t really deployed this in some time so I was able to make some comparisons to some of the antennas I have been working with lately, namely the 1/4 wave ground mounted verticals. Setup up was about as easy as I remembered it but certainly more complicated than the ground mounted vertical. It is also heavier than I remembered it to be. I had it setup with three guy lines and a single elevated radial and it tuned to 1.46 SWR on the 20m band. On 20m it is not a full size radiator and relies on a small coil to bring it to resonance.

Performance was actually quite good on 20m WSPR. Two days in a row I made the WSPR challenge board. It still remains about 20 spots below the nearby station of N5CEY. The number of spots on 1/2W transmit was about equal to the number of receive spots which I am finding to be a good indicator of antenna efficiency. Thais tells me what I already knew, that is, it is a good QRP field antenna.

The antenna went up Saturday afternoon and stayed up through Monday afternoon. Monday it got breezy here at the QTH. Wind speeds picked up to around 20mph with gusts to 35mph. At some point, the camera tripod failed at the point where the PVC pipe meets the tripod. The whole mess came down hard. Fortunately, the whip was spared any damage and the tripod can be repaired.

IMG_1444

For my next trick I am going to try and replace the whip with a fishing pole and wire with an elevated radial. Should be much lighter. It has also proven to be much more resistant to the “valley Wind Machine” that builds up around here this time of year.

40-20-15m EFHW Round 2 – Update

WSPR results o 40m and 20m WSPR look good with the EFHW. here is 40m during nightime hours:

2017-12-11_9-54-35

And 20m for just a few hours yesterday and so far this morning:

2017-12-11_9-55-11

On 40m there have been 103 unique heard vs 106 heard by (@1/2 W). On 20m, this is 124 unique heard vs. 74 heard by (also @1/2 W). These numbers indicate good overall performance.

I found a great write up on how to build one of these antennas titled “A Shortened Multi-band End-Fed half Wave (EFHW) Antenna for 80-10m” by Steve Nichols, G0KYA.

I am going to do some work on how to best deploy this in the field given my typical situation (i.e. lack of tall trees). this could be a great Field Day antenna.

40-20-15 EFHW Round 2

There were some things bothering me about the EFHW matchbox. I would run a scan using the RigExpert with a 3.9K Ohm resistor from the antenna line across to the ground and sometimes get a good reading and sometimes not. I suspected a poor solder connection or the el cheapo binding posts I was using. Well I am done with the el cheapo binding posts! From now on I am using stainless steel machine screw hardware. I replaced the binding posts with these and the readings settled out.

I made a few other changes for round 2 with this antenna today. First up, I wrapped the end of the RG-58 cable eights times around an FT240-43 core to act as a choke at the feedpoint. I added about six feet of counterpoise. I went back to setting this up a a low inverted V of sorts. The feedpoint is over a tree branch on one end about 6 feet off the ground. The other end is supported by a fishing pole. Unfortunately, this configuration had a huge amount of sag in the middle. I placed another pole in the middle so the apex is up about 16 feet. Not happy with this configuration. I will use a sturdier pole and set this up as a true inverted v next time around. meanwhile, I am running some test in this configuration. SWR was good on 40m and 20m but a bit high on 15m:

efhw

Initial WSPR results on 20m look promising. 1/2W signal is showing a good ratio to received spots. I tried a few SSB contacts but none were closed. I’ll run WSPR on this over night on 40m and 20m and see what the data shows. I’ll then switch to a 10m pole to support the middle of the wire into an inverted V.

One more thought is that I’ll add a 110uH coil to the end of the wire then about 2m more of wire, the idea that it can trap 40m and then act as a loading coil on 80m. I have worked out the coil dims for this using a 1-1/4″ PVC pipe coupler as a coil form. 110uH works out to 52 turns of #20 magnet wire.

40-20-15 EFHW

Here are the 24 hour WSPR results on 40-20-15m receive using band hopping. They appear to be pretty consistent with current band conditions and while not as good as the 1/4 wave vertical it is a very respectable and very portable multi-band antenna.

40m40m

20m20m

15m15m

The SWR plot is as follows:

swr

These antennas are increasingly popular and many quality antennas sell for ~$140. Building your own is very simple and I would estimate my cost to build this would not be greater than $30. This will work out to be a good antenna for portable or field day use. It is not especially sensitive to mounting or orientation.

 

EFHW Broadband Transformer On the Air

Back in late August, I had a post regarding a broadband auto transformer for an EFHW antenna. I finally got around to cutting 66ft of wire (1/2 wave on 40m) and did some basic tests. It is only up about 10 ft and stretched out north-south across the back yard. The RigExpert Zoom showed dips in the 40m, 20m & 15m bands. SWR is below 2:1 across each band. Twenty-five feet of coax forms the counterpoise. Very promising. One SSB contact on 20m yielded a 57 report on this antenna and the 1/4 wave vertical. I am running WSPR now on 40m. Tomorrow I will raise this up to a least 20ft and run some more tests. If I add another 66ft it will be a 1/2 wave on 80m and should get me a match on all bands (except 60m) between 80m and 10m.

More Test Results of The Ground Beam QEC Antenna

Tried 20m FT-8 early this morning as VOACAP indicated this was the best time for EU contacts on this band. My signals were heard toward the Northeast US but very few were heard in the EU. I made no QSO’s. WSPR results over 24 hours are here:

wspr mapo

This data appears to confirm that this antenna is directional (I have it pointed at a 45° bearing from my QTH)  but the F/B ratio is still relatively poor. The antenna is about the same as the 1/4 wave vertical overall. I must say that my single reports in the forward direction on SSB have been very good. Propagation on 20m is not helping. VOACAP shows the following based on 100W SSB with the receiving antenna based on a dipole at 10m:

prop1prop2

20m has been largely dead after dark. This chart indicates that 20m contacts with this combination of antennas and power will be challenging to the EU.

Overall, The ground beam – QEC antenna is an easy to carry and deploy vertical antenna with just enough directionality to help in some situation. It is well suited to my QTH on filed day as it has a wide enough bandwidth to cover the USA and Canada.