Monthly Archives: May 2016

KA9EAK Portable – 6m

The weather was beautiful today and I really didn’t want to do anything that I needed to do so it sounded like a perfect day for Amateur Radio. I checked various propagation sites and saw that 6m was open. This combined with the fact that I had a new (to me) Par Electronics SM-50 6m Stressed Moxon waiting to be deployed made for a good day for portable operation.

I’ve wanted to get one of the Par Moxons for awhile and found one at the ORC spring hamfest. It was complete in the original box and the price was right so it followed me home. The antenna gets really good reviews on eHam and is perfect for portable operation. It is very easy to assemble and is very well made. The reflector is a piece of Flex Weave wire with ring lugs on the ends that screw into the arms that lead out from the driven element causing them to bow in a wee bit. I placed it on the top of a bit over 20 feet of pipe welded together for just this purpose and fed it with about 30 feet of RG-8U.

6m stressed Moxon

6m stressed Moxon

Antenna at a bit over 20 feet

Antenna at about 20 feet

By the time that I got the antenna up and the rest of the station (Kenwood TS-480SAT) assembled the band was starting to get busy. I went to the SSB calling frequency, 50.125 and listened for a bit, hearing nothing I called CQ and got an almost immediate response from WA1T in New Hampshire. Great signal reports both ways and I was working off the side of the antenna at that point. Using my armstrong rotator I moved the antenna around and moved up and down a bit on the band from 50.125 to 50.150 looking for stations. In less than two hours of operation I had made a dozen contacts, most with good signal reports though with some effort as the band moved around. Some stations were there and strong and the next instant they were gone so some contacts were missed. Most all of the stations I contacted were running as much or more power and had larger antennas than I so it was good that they had better ears than mine, but the little Moxon on some pipe in the backyard performed well. More investigation is required in order to determine if the pile of flowers at the base of the mast had any influence on signal strength. Could this be the origin of the phrase “flower power?”

Portable station

Portable station

I heard\called a few Texas stations but the only one that heard me was K5HGX. I also heard\called some stations in zero-land but was unable to complete any contacts.

Map of contacts

Map of contacts

It was a fun afternoon trying out the new Moxon and operating a portable 6m station. Now that I have this nice antenna I’ll be watching for 6m band openings.

Your host enjoying the best hobby of all

Your host enjoying the best hobby of all

 

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EARCHI antenna test

With the matchbox completed the next step was to attach the antenna wire and perform some further testing in addition to some operating.

The recommended antenna wire length is 30 feet. I chose to use Wireman 532. I also chose to use a counterpoise of 16 feet of Wireman 532. The coax feedline can also serve as a counterpoise but I read varying reports of improved results with a wire counterpoise so I choose to experiment with and without one.

The antenna was supported by a Spiderbeam 12m fiberglass pole. I taped the end of the antenna to the tip of the Spiderbeam pole and stood it up, bungee corded to a picnic table.

For the first day of testing I had assistance from a friend of the  family, Ross, who is interested in Amateur Radio. It was nice to be able to show him that antennas can be as simple as a piece of wire in the air. The first day of testing I simply used my TS-480SAT, a Welz SP-220 SWR meter, and a Dentron JR Monitor antenna tuner. Power was provided by a trolling motor battery.

Portable radio setup

Portable radio setup

I hooked up the antenna, went to 20m, and checked the tune of the antenna. After a few tweeks to the Dentron I was able to work W3US, an NPOTA station at NP52, Theodore Roosevelt National Park in North Dakota. A wee bit later I attempted to break a giant pile-up with IZ5HZO and IU5DBS to no avail. Ross was suitably impressed that I could sit in my backyard in Jackson, WI and communicate with people with a piece of wire.

The first day of testing it was nice and calm. The second day that I tested it was quite a bit more windy and warm. The Spiderbeam pole collapsed on itself three times so I added some masking tape to the joints and there were no further problems.

On the second day of testing I had help from a friend and fellow operator, Josh KD9DZP who’s a newly minted General class ticket holder. Josh recently bought a used Kenwood TS-590S that we were going to A\B test with my TS-480 but we ran out of time. We’ll get to it another day.

EARCHI antenna on a Spiderbeam pole

EARCHI antenna on a Spiderbeam pole

The matchbox was dangling in mid-air about 9-10 feet from the ground. The feedline was 20 feet of RG-8X.

Matchbox

Matchbox

The cat took a well earned nap after chasing the antenna wire and walking on the feedline while putting the antenna up. He’s a big help.

Cat nap in action

Cat nap in action

Testing with the MFJ-259B directly (no tuner) both with and without a counterpoise gave the following results:

20m SWR readings
(Direct – no tuner)
Feedline – 20 ft, RG-8X
Counterpoise (cp) – 16 ft. Wireman 532

Frequency w/ cp w/o cp
14.150 7.9 6.3
14.200 7.7 6.5
14.250 7.7 6.5
14.300 7.7 6.5
14.350 7.6 6.6

40m SWR readings
(Direct – no tuner)
Feedline – 20 ft, RG-8X
Counterpoise (cp) – 16 ft. Wireman 532

Frequency w/ cp w/o cp
7.125 3.5 5.7
7.225 4.4 5.7
7.300 3.5 5.7

10m SWR readings
(Direct – no tuner)
Feedline – 20 ft, RG-8X
Counterpoise (cp) – 16 ft. Wireman 532 (I didn’t test 10m w/o counterpoise)

Frequency w/ cp w/o cp
28.300 1.5 x
28.500 1.6 x
28.700 1.7 x
28.900 1.7 x
29.100 1.8 x
29.300 2.0 x
29.500 1.8 x
29.700 2.0 x

6m SWR readings
(Direct – no tuner)
Feedline – 20 ft, RG-8X
Counterpoise (cp) – 16 ft. Wireman 532

Frequency w/ cp w/o cp
50 4.8 4.6
52 4.3 3.7
53 3.6 3.1
54 4.3 3.7

So far the antenna appears to be working well enough to add it to my portable operation. I have some more experimenting to do with the counterpoise and varying it’s length in addition to varying the length of the antenna itself.

There are a lot of resources for EARCHI antennas specifically and end fed antennas in general and I found these two blog posts helpful:

Portable Antennas: The EARCHI End Fed

Fine Tuning the End Fed Antenna

 

EARCHI antenna

The antenna I used for portable operation  last year was the BuddiPole of friend and fellow radio operator Mike, AB9ON. BuddiPoles clearly work but I wanted to build some wire antennas in order to have some additional options. The first antenna on the list is the EARCHI End Fed 6–40 meter multiband HF antenna. The EARC club used to sell kits but they don’t anymore however the instructions are on their site here and it’s certainly not a difficult antenna to build.

The first thing that you need to do is to build the 9:1 matching transformer. It is built on a T130-2 toroid.

T130-2 Toroid

T130-2 Toroid

The instructions are plenty clear as to how to wind the transformer.

Winding complete

Winding complete

Transformer complete

Transformer complete

For the enclosure I choose a Hammond 1591B. It’s nice and small and I like the transparent blue but the side walls are a bit short so you will need to use a bulkhead chassis mount SO-239 instead of a flange chassis mount as there isn’t enough room to mount the latter.

Installed in project box with connectors

Installed in project box with connectors

Once the matchbox was completed I tested it with my MFJ-259B. I soldered some resistors in series to get 450Ω (in this case 491Ω) with the expectation of seeing around 50Ω through the frequency range.

Testing with MFJ-259B

Testing with MFJ-259B

Results were as follows:

Test results

Test results

 

Frequency R Ω SWR
7.000 30 2.8
7.300 31 2.7
14.000 60 1.7
14.350 60 1.7
21.000 62 1.5
21.450 62 1.5
28.000 55 1.5
29.700 58 1.5
50.000 116 3.0
54.000 148 3.7

It stays around 50Ω through the intended frequency range with the exception of 6m but that’s OK. I have other antenna choices for 6m.

The next thing to do is to attach the antenna wire and try it out.

 

Tarheel II antenna

Thus far I am really pleased with my Little Tarheel II antenna. It performs well for my mobile station. I recently purchased the 54″ whip for it so I have both 32″ and 54″ whips.

Today was the first day in which the weather was finally nice enough to do some testing across multiple bands. I’ve mainly been operating on 20M and a wee bit on 40M.

On 20M with the 54″ whip the antenna appears to be largely flat across the phone portion of the band. The SWR is around 1:1.1 and barely moves from 14.150 to 14.350. The tuned position on 20M looks like this:

20M setting

20M setting

On 40M with the 54″ whip it’s nowhere near a broad banded. Setting the SWR at the center of the 40M phone band (approx. 7.212) the SWR moves to 10:1 at 7.125 and at 7.298. The good news is that it only takes a minor tweak to tune the antenna. From band end to band end the antenna only moves about 3/16″. The tuned position on 40M looks like this:

40M tune

40M setting

On 10M from 28.300 through 29.7 it does pretty well with much less of an SWR swing than on 40M. To go from 1:1.4 at 28.300 to the same SWR at 29.700 is one blip of the antenna motor switch up or down depending upon which direction you are going on the band. How much is a blip? Literally just a momentary click of the switch is all it takes to move from one end of the band to the other. The tuned position on 10M looks like this:

10M Tune

10M Setting

On 6M I was unable to obtain an SWR less than 3:1 with the 54″ whip. I switched to the 32″ whip and was able to easily cover the SSB portions of the band without moving the antenna much if at all.

I’m pleased with these results and an starting to get a reasonable feel for tuning the antenna for optimal operation.

I’ve added the Tarheel quick disconnects to ease changing the whips. They are very nice and quite substantial. They are well worth the price.

Tarheel Quick Disconnects

Tarheel Quick Disconnects

 

KA9EAK Mobile

I recently put together my first HF mobile station. It consists of the Yaesu FT-857D that I purchased two years ago and a Little Tarheel II antenna that I recently purchased.

My initial plan for a mobile antenna was to use a set of original Hamsticks that I obtained from various sources. These are very nice HF antennas but the primary drawback with them was that they are very long and I need to clear the parking garage at work and to do so requires the removal of the entire Hamstick assembly (base and whip) and then tucking this all away in my Corolla. This wasn’t the best setup given the parking constraint. A friend and fellow radio operator, Rick, AB9XI has used the same Tarheel for his mobile station for awhile with good results. So after a lot of consideration I purchased the Tarheel.

FT-857D in my Corolla

FT-857D in my Corolla

The radio, speaker, and mic clip are all mounted on a Plexiglass block which is in turn mounted on a gooseneck mount (AES MT-7) that I purchased from AES.

Plexiglass mount

This makes it easy to remove the head and associated parts.

The Little Tarheel II is mounted on a Comet HD-5 mount:

Little Tarheel II on Comet HD-5

Comet HD-5 mount and ground

The ground strap runs down to the main portion of the car body and is just a portion of the grounding\bonding that I’ve done for the installation.

I don’t have to tune the antenna anywhere near as much as I expected. For logging I simply use the Voice Memo app on my phone to record the particulars of each contact and then enter them into my log (N3FJP) when I get home. Rick, AB9XI runs a wireless network with his iPad for logging using the Piglet and Hamlog from Pignology. I’m not going to go that far yet.

In three weeks of operation this mobile station is performing quite well. In addition to a handful or more US stations I’ve contacted some DX stations as well:

KP4EML in Puerto Rico
VP9KD in Bermuda
OK2RZ in Czech Republic
WP2B in St. Thomas, VI

All on 20M and all with good signal reports. The distance to OK2RZ’s station is around 4600 miles though to be fair he has an antenna system that could likely hear a QRP station on Pluto! But still, 100W with a trunklid mount antenna on a Toyota Corolla motoring along in Wisconsin talking to people thousands of miles away is the amazing part of Amateur Radio.