Monthly Archives: August 2017

A Cool Idea for a 20m Hamstick

I found this configuration for a single 20m hamstick antenna which may be a winner for balcony operation at South Padre Island. The hamstick connects to a T connector. One end of the T connector goes to the feed line and the radio. The other end has a shorted 1/4 wave length (corrected for cable VF) of coax as a counterpoise. Here is the configuration (thanks to PD7MAA):

no ground antenna

This assumes the stub is RG-58 with a velocity factor of 0.66. Other coax types simply calulate based on the new velocity factor.

Advertisements

Antenna Experiments Continue

First up is a broadband EFHW using an auto-transformer wound on an FT240-43 Ferrite toroid. I used 18 gauge doorbell wire (had to remove the outer jacket of the wire pair first. The basic wiring looks like this (thanks to PA3HHO):

2017-08-31_10-40-14

What is not shown here is a 150pF capacitor across points A & B. Here is the completed toroid:

20170831_153149704_iOS

Here I test the matching by connecting a 3.9KOhm resistor across point B & C along with the 150pF capacitor across A & B. Here is the SWR plot:

20170831_153018134_iOS

SWR is below 2:1 across nearly the entire band 80m to 12m 10m is 5:1 well within range of a tuner. I will mount this in a box with a UHF connector and two banana jacks, One for the antenna wire and the other as a ground connection. Once complete I’ll try first with 40m 1/2 wave wire. That should give me a good match on 40m, 20m, and 15m. The wire will be around 66 ft long.  I should be able to add 80m by adding a loading coil and an additional 2.5m piece of wire. Planning to un the first 10m of wire up the travel mast then bring the rest down as a sloper.

New Antenna Projects

I am going to build a matching transformer for a multiband EFHW antenna. The idea is to use a 1/2 wave wire and not have to use a tuner across several bands. More details to come. Also will build an inverted V for 20m to use as a reference antenna.

ICOM 7300 – First Impressions

I spent some time playing with the new IC-7300 transceiver this weekend on various modes. My first comment is that having used an IC-7100 for some time I was instantly familiar with about 90% of the IC-7300 controls. Most of the buttons are labeled the same and many of the setting menus are also the same. First thing I installed was a headset adapter so I can use the Koss SB-45 headset. I needed a plug adapter (which I luckily had on hand) to plug in my Vibroplex paddles. Rig control via Ham Radio Deluxe was fairly straightforward as the USB drivers are the same as the IC-7100.  I started operating on 20m during the North America QSO party on Saturday with the 1/4 wave verticals.

My first impressions are that the rig works well (and possibly better) than the IC-7100 on SSB. My signal reports were solid 59’s and occasionally 59+ all across the USA. Also made some DX with favorable reports.  Receive options make it easy to adjust RF gain controls and filters to help clean up the signals. I like the overload indicator which tells me to back off on the preamp or RF gain or both. The main learning curve for me thus far is in using the scope screen. Once you play with this awhile you get used to operating more visually. You can see whats going on across the whole band and find signals to tune into or find dead spots where the frequency is open. It is also easy to switch in the audio monitor to hear what you are transmitting.

Also tested digital modes JT-65, FT-8 and PSK31 after configuring the software for the rig. The audio scope helps look at the signal quality on digital modes. I did not find any notable differences in using the 7300 vs the 7100 on digital.

So overall I am impressed by the new rig especially on SSB Phone. I’ll likely expand on this review as I get some more time on the rig but I am happy with what I have seen thus far.

The IC-7100 is now setup as my base VHF/UHF rig and I hope to play with DSTAR on it for the first time sooner rather than later. I will continue to have it connected to my PC for rig control and can switch in HF when needed.

Ham Shack Changes – Part I

I made some changes to the Shack today. First up was removing the FT-450D and the FT-2900R and their associated cabling. The FT-450D will become a portable station along with an MFJ-4230MVp Power Supply in a pelican style case. The FT-2900R will eventually make its way into my Ford F-150 for 2m mobile operation. The IC-7100 is now working as my VHF/UHF rig. I have kept the rig control and HF connection intact so I can also use it on HF. I have now installed a new Icom IC-7300 for my HF base rig. Installation was stratight forward and operation is VERY similar to the IC-7100. The main new features are of course the spectrum scope and the filtering. I have Ham Radio Deluxe, N1MM+, JTDX and WSJT-X configured and working with the new rig.

Today is the North America QSO Party so there is an active band on 20m to play with the new rig. I’ll review later as I have more operating time built up on the rig. Here is the new “minimalist shack”…so far:

20170819_210827390_iOS

Addtional changes in the works are:

  1. Swap my ground braided strap connections with copper strap.
  2. Install S9 Antenna and radial plate
  3. Secure the FT-450D and FT-2900R in their new homes

WSPR Data collected from the 20m Hamstick Vertical Dipole

Here is 24 hours of WSPR data collected from the 20m Vertical Dipole:

20170814_013033000_iOS

There were 114 unique receive spots and 90 unique heard from spots with 1W transmit. This seems low compared to N5Cey’s 20m 1/4 wave vertical which typically receives 180 to 200 unique spots from his QTH near Los Fresnos.

I did some A vs. B tests on SSB yesterday switching between the 1/4 wave vertical and the vertical dipole. This time I used a remote receiver using Websdr.org. I connected to a station in the San Fransisco area and monitored my voice transmissions. In this case the vertical dipole came in about 1 S units stronger. I then switched to a station in New Jersey and the opposite was true!

I am going to do some additional testing on various 20m vertical configurations using WSPR over the next couple of days.

Major Changes to the Ham Shack are Planned…

ico-ic-7300_it_xl

…enough said for now…

A 20m Vertical Dipole…(I am a glutton for punishment)…

Here in South Texas you hear a lot about the Canicula. July 14 through August 24th is considered to be the hottest part of the year. It’s 94° F here today but when you add the 54% humidity we get a heat index of 106° F. So naturally I choose today to play with a new antenna!

I built a vertical dipole for 20m today using two Workman Hamsticks. I thought this would be fairly easy as I didn’t have to get it too far off the ground. More on that later…

I read that one ham had pretty good luck with the stinger set at 38″ so I set that as a starting point. I set it up vertically on a painters pole with the bottom stinger about a foot off the ground and found the SWR minimum was in the 13.5 Mhz range. I shortend the stingers and the SWR went down to the 13 Mhz range. I played with this for some time until the whole mess collapsed in the breeze. Arrrgh!

I came inside and after re-hydrating played around with the antenna again. Nothing I did seemsed to work in getting it to tune in the 14m band. I got it back to the original configuration and ventured outside again. I set it up as before and the SWR was in the 13.5Mhz range again. This time I guyed the painters pole and sent it up a few feet. The SWR started going down with the minimum frequency going up into the 20m band…Aha! I raised it up so the feed point was about 15 to 16 ft off the ground. This put the end of the stinger at about 8 feet.  Now the SWR response looked good with 2:1 or less across most of the 20m band.

Inside again now I started to tune around and found the SWR swinging again. Suspected Common Mode Currents again so went outside and lowered the antenna to 8 feet, redressed the coax so that it comes out away from the feed point at 90° for about three feet. Now everything is working out fine. I made an SSB contact to Chile and to Guatemala right off.

So here is what I learned today:

  1. It is too hot in South Texas in August to play with antennas…wait till early morning or very late in the afternoon next time.
  2. A vertical dipole needs to be a few feet off the ground to tune properly
  3. It is vitally important that the coax feed line in a vertical dipole come out at at 90° angle for several feet to avoid common mode currents.

Here is a view of the antenna:

20170812_213525961_iOS

Here is the SWR plot:

20m dipole vert

Will run 1W WSPR for 24 hours and compare data with the 1/4 Wave vertical.

 

 

My Ugly Balun

I built an ugly balun today to try and address the SWR swings I was getting on 20m. It actually went together in about 10 minutes. To build it I used a 4″ PVC pipe coupler as a form. I drilled two small holes to run a tie wrap through to hold the end of the coax in place. I had a 25 foot piece of RG-8X laying around with PL-259 connectors on each end. I wrapped 15 turns around the coupler and then tied it off the same was as the other end. Some long tie wraps then are used to hold the winding securely on the form. I replaced the 1:1 current balun I had been using with this. To match up the coax connectors I used two bulkhead connectors and wrapped with electrical tape (for now). Here’s what the finished balun looks like:

20170809_225801226_iOS

And here it is installed at the vertical antenna feedpoint:

20170810_003629514_iOS

 

The balun seems to help with the SWR issues on 20m but I see some shifts in the overall SWR response. I’ll likely have to tweak that over the next few days.I have some ferrite toroids on the way as well and will try and build a choke with those as well. Signal reports on both 40m and 20m SSB were real good tonight!

 

What’s Better than One 1/4 Wave Vertical? —How About Two?…

Next experiment in vertical HF antennas is trying a 1/4 wave vertical “fan dipole”. The 7.2m fishing rods are a perfect support for up to a 20m wire radiator. I set a length of 3/4″ PVC pipe about a foot away from the existing 40m 1/4 antenna. I also removed the last two section of fishing pole as they are too flimsy and are not needed length to support a 20m wire. I connected this wire to the point where the 40m wire connects and after a bit of tuning had three dips in the SWR. 7 MHz is the main tuned frequency, 14 MHz is the new radiator and 21 MHz is the third harmonic of the main radiator. Here is the SWR plot:

swr

Here is what is looks like:

20170805_225609323_iOS20170805_225616530_iOS

So far this works well as before on 40m and 15m. The performance on 20m looks a little shaky still as I am seeing my SWR swing around a bit when transmitting. This indicates to me that my feed line is picking up RF at that frequency. I’ll be building an Ugly Balun soon to try and clean that up. The antenna hears very well on 20m with very little noise so I f I can solve the SWR issue I should be in good shape.