Author Archives: AB1OC

2013 Amateur Radio Highlights

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DXCCs Worked in 2013

DXCCs Worked in 2013

Anita and I were quite active on the bands in 2013. Together we made 20,650+ contacts from a combination of our home and mobile stations and we worked a combined 259 DXCC Entities.

Combined 2013 QSOs By Band

Combined 2013 QSOs By Band

We were active on all of the Amateur Bands available in the USA from 160m through 70cm except for the 60m and 1.25m bands. The picture above shows the distribution of our QSOs across the bands in 2013. Both of us participated in quite a few contests in 2013 and this resulted in the 5 major contest bands dominating our operating activity. I did quite a lot of work on the 160m band this year and I participated in several 160m contests to gain experience and to begin working towards a DXCC on this band. We worked a total of 50 DXCC Entities on 160m in 2013. Our 6m, 2m, and 440 MHz (70cm) contacts were made mostly during VHF/UHF contests that I participated in.

Combined 2013 QSOs By Mode

Combined 2013 QSOs By Mode

We like to operate using many different modes. Anita (AB1QB) does quite a bit of RTTY contesting and she accounted for the bulk of the activity in the digital modes from our station in 2013. I made it a point to become active using the CW mode this year and I made 1,550+ contacts using CW in 2013 including participation in several CW contests. Operations in SSB Phone mode dominated our activity this year mostly due to our operations in SSB Phone contests and as one of the New Hampshire Stations in the 2013 Colonies Special Event this year where we made a combined total of 6,200+ contacts.

QSL Cards Ready To Mail

QSL Cards Ready To Mail

We really enjoy sending and receiving QSL cards. We sent 5,800+ QSL cards this year, averaging approximately 110 cards sent each week. We also QSL’ed via eQSL and Logbook Of The World. I am often asked what percentage of our QSL requests are confirmed. For 2013, we received confirmations for 67% of our direct/bureau cards, 31% of the QSOs uploaded to eQSL, and 37% of the QSOs upload to LoTW. These numbers will undoubtedly rise a time goes by.

AB1OC Operating Awards

AB1OC Operating Awards

All of this operating allowed us to complete a number of operating awards this year. Fred completed his DXCC Challenge, 8-Band DXCC, and CQ WPX Award of Excellence Awards as well as a DXCC Awards in CW mode and a DXCC QRP (5 watts).

AB1QB Japan Cities Award

AB1QB Japan Century Cities Award

Anita has held a DXCC for some time and has been focusing on a number of JARL Awards. She completed her Japan Century Cities Award for confirming contacts with 100 cities in Japan in 2013.

AB1QB Operating In The BARTG RTTY Contest

AB1QB Operating In The BARTG RTTY Contest

Contesting was a big part of the operations from our station this year. I was active in several major SSB and CW contests this year and Anita was active in quite a few major RTTY and phone contests as well. We are both licensed for less that 3 years and have been competing in the Rookie or Novice categories in most contests and we have been doing quite well. Anita took 5th place in the world in the 2013 BARTG RTTY Contest and she has placed 1st in our call area in several of the 2013 ARRL Rookie Roundups in both SSB Phone and RTTY.

2013 CQ Worldwide WPX SSB Certificate

2013 CQ Worldwide WPX SSB Certificate

I placed 1st in North America/2nd in the World in the 2013 CQ WPX SSB Contest (Rookie High Power) and 1st in North America/2nd in the World in the 2013 CQ WPX CW Contest (Rookie High Power). Contests have provided us a great deal of operating experience and have contributed greatly to our completion of several operating awards.

Mobile Installation In Ford F-150

Mobile Installation In Ford F-150

Station Building was a big part of our Amateur Radio experience again in 2013. We installed a mobile HF setup in our truck and did quite a bit of mobile HF operating. We made 165 contacts from our mobile station in 2013 and worked 41 DXCC entities.

WSJT EME QSO - Waterfall

WSJT EME QSO – Waterfall

I also made my first Earth-Moon-Earth Contacts on 2m in 2013. I made 30 contacts on 2m using the moon as a reflector, working a total of 16 DXCC Entities this way.

AB1QB Operating The Flex-3000 Software Defined Radio

AB1QB Operating The Flex-3000 Software Defined Radio

We added a Flex-3000 Software Defined Radio (SDR) to our station in 2013 and have been using it to learn about this new technology. The performance and operating capabilities of SDR are making SDR a big part of the future of Amateur Radio in our opinion.

8-Circle Receive Array System Diagram

8-Circle Receive Array System Diagram

Antenna projects were also a part of our station building work in 2013. We installed an 8-Circle Receive Array System for 160m – 40m and this new antenna system helped us a great deal with DX’ing and contesting on 160m and 80m. We also began the reinstallation of our BigIR Vertical Antenna but the onset of winter here in New Hampshire caused us to delay the completion of this project until spring. Finally, we made the switch to the excellent DXLab logging and DX’ing software suite. DXLab helped us a great deal with QSL’ing and tracking our progress toward operating awards.

CW Station Operations

2013 Field Day CW Station Operations

We were part of the 2013 Field Day team at our local radio Club (PART in Westford, MA). We provided and managed the digital station as well as the setup of a portion of the antenna systems for our club’s field day operations.

ARRL At Dayton 2013

ARRL At Dayton 2013

Anita and I attended the Dayton Hamvention again in 2013. The Dayton event is always a great opportunity to see the latest in Amateur Radio equipment. We attended the 2013 Contest University which was held as part of the Dayton Event and used the information that we learned there to continue to improve our contesting skills.

Fred Lloyd AA7BQ, Founder Of QRZ.com

Fred Lloyd AA7BQ, Founder Of QRZ.com

The internet was a big part of our Amateur Radio experience again in 2013. We met Fred Lloyd, AA7BQ who visited us to do an article on QRZ.com on our station. We learned a great deal from Fred during the time that we spent with him as part of this project. We published 47 new articles here on our blog in 2013 and have received over 45,000 views from our readers in 152 countries around the world. We really appreciate the interest from the HAM community and we will continue to publish new articles here in 2014.

As you can tell from this article, 2013 has been a very active year for Anita and I. I’ve created the video above to give you some idea of the contacts that we have been fortunate enough to make around the world in 2013. We hope you enjoy it and we want to thank everyone who has taken the time to work us, to end us a QSL card or to read the articles that we have written here.

– Fred (AB1OC)

An New QRP Operating Award

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1,000 Mile Per Watt Award

1,000 Mile Per Watt Award

I did quite a bit of operating at QRP power levels (5 Watts) in 2013. It is great fun to make contacts at low power and it is truly amazing how far one can communicate on only 5 watts of power. QRP operating is also a great way to improve one’s operating skills. I recently discovered an award run by the QRP Amateur Radio Club International called the 1,000 Mile Per Watt Award. I completed a QRP DXCC Award in 2013 so I have quite a few DX QSO’s at QRP power levels. After looking at my log, I discovered that my longest QRP CW contact was with Alan Taylor, VK7BO in Tasmania, Australia – some 10,470 miles from our station. I used this contact to apply for the 1,000 Mile Per Watt Award you see above. This award will make a nice addition to the wall in our shack.

– Fred (AB1OC)

First QSOs On The 60m Band

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60M Band Plan

60m Band Plan (from ARRL Band Plan Chart)

The 60m Band is a relatively new allocation for Amateur Radio Operators in North America. I’ve long wanted to try this band so last evening I took some time to understand what was required and to determine if my available antennas were up to the task. U.S. Amateur Radio operators with a General Class or higher license have secondary privileges on the 60m band. U.S. HAMs can use either USB Phone, CW, or a limited set of digital modes on 60m. The band is “channelized” meaning that one must operate on specific frequencies only. For Phone communications, one must use USB mode only, limit the bandwidth of your signal to 2.8 kHz (most rigs operate USB at a 2.4 kHz bandwidth) and you must set your rig’s frequencies to one of the values shown above corresponding to the five available channels. These same frequencies/channels would be used for digital modes such as PSK31 or RTTY  (see the article on this blog for information on how to get started if your interested in operating using digital modes). For CW operation, you need to set your rig to 1.5 kHz above the frequencies indicated above which will ensure your CW signal is in the center of the associated channel. The highest frequency channel (5403.5 kHz) is shared by HAMs in the U.K. and often provides opportunities to work DX on 60m.

There is an 100W Effective Radiated Power (ERP) limit on this band. See the following page on the ARRL site for information on channel allocations and operating tips. There is also an excellent 60m FAQ page on the ARRL site.

*** Note that this information was taken from the ARRL website and is presumed to be correct for U.S.-based HAMs at the time this article was written. I recommend that  you consult the ARRL website or the equivalent source for license information in your home country prior to operating on 60m to obtain the most up to date operating privileges and rules for the 60m band as they pertain to your home country and license class ***

DXLab Commander 60m Setup

DXLab Commander 60m Setup

Most modern rigs can be tuned to the frequencies used on the 60m band. To make this easy to do and error free, I configured the rig control application in the DXLab Logging Suite which I use to set my transceiver to the correct frequencies, bandwidths and modes corresponding to the five 60m channel allocations for Phone/Digital and CW.

Delta Loop On Tower

75M Delta Loop On Tower

The next step was to determine which of my available transmit antennas would work on the 60m band. After some checking with an antenna analyzer, I determined that the 75m Delta Loop on our tower would tune up well enough to use as a 60m transmit antenna (the feed point for the Delta Loop is on the white fiberglass rod which protrudes to the left of the tower about 15 ft up in the picture above and the apex of the loop is suspended from the upper set of guy cables). I also have a SteppIR BigIR Vertical which will work on 60m but I don’t have that antenna completely installed yet.

The 100W ERP power limit on the 60m band is relative to a Dipole antenna with 100W PEP in. If your antenna has gain relative to a dipole your must adjust your power out accordingly. For example, if your antenna has 3 dBd (3 dB gain relative to a dipole), then you’d be limited to 50W PEP output (50W PEP out + 3 dB gain = 100W ERP). You can use the following link to a handy dB calculator to help you do this calculation if your antenna requires it. Also note that you are required to maintain records based on manufacturer’s antenna gain specifications or equivalent information for your 60m transmit antenna.

8-Circle Low-Bande Receive System

8-Circle Low-Bande Receive System

The Delta Loop also makes a fairly effective receive antenna on 60m. Fortunately, we installed an 8-Circle Directional Receive System for 160m – 40m this past summer and this system works very well as a directional receive antenna on 60m. The 8-circle System has about 10 dB Front to Back performance on the 60m band and is considerably less noisy than the Delta Loop.

I could hardly have picked a better time to begin operating on 60m. It turned out that Canada had just granted 60m privileges to Canadian HAMs on a broad basis on the same day! This will no doubt create many additional opportunities for contacts on the 60m band.  Wikipedia provides an excellent overview of regulatory information associated with the 60m band as well as up to date information on countries which provide 60m band privileges around the world. My very first contact on 60m was a phone QSO with Joe VE3BW in Ontario, Canada. I was also able to work some additional DX including Dragan 9A6W in Croatia, Bo OZ8ABE in Denmark, and Rick, G3XAJ in the U.K. The best part about the 60m band is the relaxed atmosphere I found there. I encountered many HAMs were willing to have a nice conversation and this coupled with surprisingly quiet band conditions made the  15 or so contacts that I have completed to date on 60m a very positive experience.

I’d encourage our readers to give 60m a try. Many antennas such as OCF dipoles, G5RVs, open-wire fed dipoles and long wires will tune up reasonable well on the 60m band and the 100W ERP limit is a good equalizer for small and medium HF stations. I hope to work you on 60m in the near future!

– Fred (AB1OC)

Our Station On QRZ.com

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Our Shack On QRZ.com

Our Shack On QRZ.com

A few months ago, Fred Lloyd AA7BQ, President and Founder of QRZ.com visited our station to gather information and pictures for an article on QRZ.com. Fred’s article recently appeared and he did a wonderful job describing and photographing our shack and our station.

Our Tower and Antennas

Our Tower and Antennas

Fred is a great photographer and he has a real knack for using interesting angles to make his photographs interesting. We particularly like this one of our Tower and Antennas.

A special thanks to Fred Lloyd and everyone on QRZ.com who commented on our station. We’re happy to have some new followers of our Blog as a result of the article on QRZ.com and I am planning to write a number of new posts here over the next several weeks. Stay tuned…

– Fred (AB1OC)

Cool Amateur Radio Site – DXHeat.com

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DXHeat Website

DXHeat Website

Occasionally, something new and useful comes along on the internet for HAMs. I believe that DXHeat.com is a recent example of this. DXHeat.com has been put together by Tobias Wellnitz, DH1TW. DXHeat.com takes an innovative, analytics-based approach to DX Cluster search and data display. Big Data Analytics is certainly a key future technology for internet and other applications and Tobias has created an interesting application of this technology for HAM Spotting Cluster data access.

Cluster Spot Analytics

Cluster Spot Analytics

To give you an idea of how this works, I entered by callsign (AB1OC) into DXHeat.com’s cluster search engine. The graphic above is a snapshot of the result. As you can see, the site not only produces a list of the spots of my callsign but it also created graphical views showing the bands, dates and times where I was spotted as well as the source (continents) where the spots were originated. This information gives me a better picture of where I am being heard on various bands for example.

Online SDR

Online SDR

DXHeat.com also includes a link to an online WebSDR which can be used to listen to stations from inside Europe on the HAM bands. It looks like Tobias plans to link his site to the WebSDR so that one can listen to a spotted station as well as tune the bands and create new spots.

Tobias’ site is relatively new and there is a great deal of potential for enhancements to his concept. For example, one can imagine that automated phone spotting might be possible using  voice recognition technology sometime in the future. It will be interesting to watch how DXHeat.com evolves. Thanks to John, W1MBG to pointing out DXHeat.com to us.

– Fred (AB1OC)

Progress On Operating Awards

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AB1OC Operating Awards

AB1OC Operating Awards

Anita and I have been working towards a number of operating awards for some time now. These awards provide lots of good motivation to get on the air, improve our operating skills and improve the performance of our station. I have recently completed two major awards – an ARRL 5 Band DXCC and a CQ WPX Award of Excellence.

AB1OC 8 Band DXCC

AB1OC 5 Band DXCC

The 5 Band DXCC requires confirmation of 100 or more DXCC entities on each of the 80m, 40m, 20m, 15m and 10m bands. I was also able to confirm 100+ entities on 30m, 17m and 12m which earned the endorsements on the base award for these additional bands. I am also working towards a 160m band endorsement which for my 5B DXCC which will be quite a challenge (I currently have 47 worked on 160m). As is the case with other DXCC awards, one can use any mode to confirm a band-entity towards this award. I used a combination of SSB, CW and Digital (mostly RTTY) to complete my 5B DXCC and I used a mix of Logbook of the World (LoTW) and Paper QSL cards to secure the necessary confirmations. This award is a good test of the DX’ing capabilities of an operator and their station and it has been a goal of mine ever since we completed our station a little over a year ago.

AB1OC WPX Award Of Excellence

AB1OC WPX Award Of Excellence

The other major award which I’ve recently completed is the CQ WPX Award Of Excellence. This award requires one to confirm a large number of unique callsign prefixes using different modes, bands and on all continents. Specifically, the award requires one to confirm 1,000 prefixes in Mixed mode and 600 prefixes in SSB and 600 prefixes in CW plus earn all 6 continental endorsements (NA, SA, EU, AF, AS, and OC), and all 5 non-WARC band endorsements (80-10 meters). I was also able to earn the Digital and 160m endorsements for this award. I am close to additional band endorsements for the 30m, 17m and 12m as well. I chose to work towards this award because it requires geographic diversity (all continents – Africa and Oceania were the most difficult) and a large number of confirmed contacts using both the SSB and CW modes. The requirement to confirm 600 unique prefixes on CW was a great motivator to develop my CW skills. This award resulted in my attaining a place on the CW WPX Honor Roll for Mixed (currently 1815 prefixes), SSB (1401 prefixes), Digital (884 prefixes) and CW (600 prefixes) as well. There is a great deal of QSL’ing work associated with this award! Fortunately, CQ allows eQSL(AG), LoTW and paper cards to be used to confirm prefixes which makes the process a little easier.

AB1QB Japan Cities Award

AB1QB Japan Century-Cities Award

Anita (AB1QB) is also working on several awards and she particularly enjoys working stations in Japan. She has completed other JARL awards and has recently completed the JARL Japan Century-Cities Award which required her to work and confirm (with cards only) 100 different cities in Japan. Anita is also working on a JARL Worked All Japan Prefectures awards which requires her to work and confirm all 47 prefectures in Japan (she currently has 37 prefectures confirmed).

QSL from Hiro San, JE7HYK in Akita Japan

QSL from Hiro San, JE7HYK in Akita Japan

Earning JARL operating awards from the eastern United States is challenging and it is a particular pleasure to exchange QSL cards with HAMs in Japan.

We are always working on new awards in our shack. I am trying to complete a 5 Band Worked All States and a WAS Triple Play Award (All 50 states confirm using SSB, Digital and CW modes). In addition to the JARL awards, Anita is working on IOTA and CQ WPX awards. All this is great fun and motivation to improve our skills and operate.

– Fred (AB1OC)

SteppIR BigIR Vertical Antenna Part 1 – Assembly & Installation

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SteppIR BigIR Vertical Antenna

SteppIR BigIR Vertical Antenna

When we installed our new tower-based antenna system last year, I was forced to take down our SteppIR BigIR Vertical Antenna to make room for the tower. We really miss having the BigIR Vertical because it provided omnidirectional coverage on all of the HF bands from 80m – 6m and is a good DX antenna due to a vertical antenna’s characteristic low-takeoff angles. The SteppIR BigIR Vertical uses a stepper motor to move a length of beryllium tape up and down inside a hollow tube effectively changing the electrical length of the antenna to tune it. The antenna also has an optional Switchable 80m Loading Coil which allows the antenna to be tuned for the 75/80m band as well. The adjustment of the length of the antenna and the coil is handled by a controller in the shack which reads the frequency of an associated radio and automatically adjusts the antenna as the radio is tuned.

Antenna Layout Plan

Antenna Layout Plan

We decided to re-condition and re-install our SteppIR BigIR Vertical in the woods in front of our house. This location was chosen as it provides adequate separation between the BigIR and our other transmit and receive antennas and is at a high spot on our lot. This area is also surrounded by some fairly wet ground which should enhance the performance of the BigIR Vertical Antenna.

Vertical Antenna Foundation

Vertical Antenna Foundation

The first step in the installation of the antenna was to dig a hole for and pour a concrete foundation for the antenna. All of the needed materials as well as a rental motorized post hole drill were obtained at our local home supply store. We used an 8″ round form and dug down approximately 3 feet into the soil to set the form. We then placed about 6″ of medium stone in the bottom of the hole and filled the form with cement. We set and plumed a piece of 2″ plastic PVC pipe in the center of the form to hold the steel pipe that mounts the BigIR Vertical Antenna.

Foundation And Base Mounting Details

Foundation And Base Mounting Details

The PVC pipe is slotted on the ends with a saw so that it will clamp and hold the BigIR mounting pipe firmly in place with the aid of two stainless steel hose clamps. The mounting pipe that comes with the BigIR is slightly smaller in diameter than the inside of the PVC pipe so a few layers of  electrical tape are used at three points on the mounting pipe to create a good fit. This approach allows the antenna and the associated mounting pipe to be removed from the foundation for use at another site if needed.

Vertical Antenna Radial Plate

Vertical Antenna Radial Plate

The next step in the installation was to assemble and mount a DX Engineering Radial Plate. This Radial Plate is an excellent part and will make it easier to attach the planned 120 radial wires to the antenna. I am using N-connectors on all of the feedline connections associated with our BigIR Vertical so I also installed a N-connector Feed Through Connector on the radial plate to enable easy grounding of the feedline coax’s shield to the radial plate and antenna.

BigIR Pre-Assembly - Element Support Tube (EST) Joint Sealing

BigIR Pre-Assembly – Element Support Tube (EST) Joint Sealing

The next step in the installation was to re-assemble the BigIR Vertical Antenna. The paint on my element housing tubes had faded quite a bit so I lightly sanded them and sprayed them with a couple of coats of Krylon U-V Resistant Clear Coat. This made the tubes look like new and provides protection from fading and weakening of the element tubes due to the effects of UV radiation. SteppIR has made several enhancements to the BigIR since I purchased it a few years back. These include a much better sealing system for the element housing tubes which makes use of heat shrink tubing (pictured above) and a High-Wind Reinforcing Kit for the antenna’s element housing and base. These updated parts and components were obtained from SteppIR for use in re-assembling the antenna. SteppIR has also improved the assembly and instruction manual considerably.

BigIR Wind Reinforcing Kit With Element Housing And Coil

BigIR Wind Reinforcing Kit With Element Housing And Coil

I first connected one end of a spool of 4 conductor control cable to the element housing and reassembled the antenna’s element housing, 80m coil, optional feedline choke balun and the wind reinforcing plate and saddles.

BigIR Pre-Assembly - Base

BigIR Pre-Assembly – Base With Both Sections Of Element Support Tubes

Next, I attached the lower section of the element support tubes to the base assembly. I also prepared the upper section of the element support tube by sealing the joints, attaching the guy rope bracket and installing the top cap/vent and rubber coupler. The antenna is over 30 feet in length when the fully assembled so its best to leave the antenna base/lower element housing tube and the upper element housing tube separated to make transporting the antenna to the site where it will be installed easier.

After transporting the pre-assembled antenna to the installation site, I next attached three lengths of Dacron Antenna Guy Rope to guy rope bracket on the antenna and assembled the two sections of the element support tube to each other, completing the assembly of the antenna.

Coupler UV Protection

Coupler UV Protection

It is a good idea to cover the rubber coupler which attaches the upper and lower element support tube sections together with several layers of electrical tape to protect the rubber coupler from UV damage.

BigIR Installed On Foundation - 80m Coil And Balun

BigIR Installed On Foundation – 80m Coil And Balun

Next I carefully lifted the antenna onto the foundation, attached the three guy ropes to their anchors and then torqued the saddle clamp bolts on the wind reinforcing bracket to 12 ft-lbs. It’s important to not over tighten the saddle clamp bolts as doing so can crack the fiberglass tubes on the antenna. The next step was to tighten the lower rubber coupling clamps, sealing the antenna’s connection to the metal tubing in the foundation.

BigIR Grounding Details

BigIR Grounding Details

The last step in the antenna installation was to connect the ground lug on the 80m coil to the radial plate using a DX Engineering Ground Strap.

BigIR Installed On Foundation - Element Housing And Control Cable

BigIR Installed On Foundation – Element Housing And Control Cable

The picture above shows the element housing side of the installed antenna. The spool of control cable will be covered with a plastic bag to protect it from the weather until the final feedline and control cable connections are run to the shack.

Guy Rope Anchor

Guy Rope Anchor

The picture above shows the details of the guy rope anchors used to secure the guy ropes on the ground. Three Earth Anchors were turned into the soil using a steel rod which provides a solid point to attach the three guy ropes. The rope tension adjusters shown in the picture above were obtained from our local hardware store.

A Stealthy Vertical Antenna In The Woods

A Stealthy Vertical Antenna In The Woods

As you can see from the picture above, the BigIR Vertical is quite stealthy when installed in the woods. While it may not seem so, the work outlined here represents the easy part of a vertical antenna installation. The real work lies in installing the radial wire field around the antenna. The radial field has a significant impact on a vertical antenna’s performance in terms of both radiation efficiency  and takeoff angle. The ground in our area is not very good so I am planning to install an extensive radial field consisting of 120 radial wires, each 110 feet in length. I will cover this part of the project along with the installation of the feedlines and control cables to the shack and the final integration and testing of our BigIR Vertical Antenna System in a future article.

– Fred (AB1OC)

Another Milestone Reached – Our Blog Receives 50,000 Views

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Readers From 152 Countries Around The World

Our Readers From 152 Countries Around The World

Our Blog reached another milestone this past weekend – 50,000 views! We have gotten to this point in a little over 1 year since we started our Blog. It was our goal from the onset to create a blog that was interesting and useful to the HAM community everywhere and I am happy to see that there is interest in our Blog worldwide. While the bulk of the activity on our Blog comes from North America and Western Europe, our readers call some 152 countries around the world home.

Anita and I would like to thank you, our readers for making our Blogging project a success. We hope to continue to provide you with interesting and useful information about station building and operations as well as other material of interest to HAMs around the world.

– Fred (AB1OC)

Receive Antenna For The Low Bands Part 3 – Connections To Shack And Final Integration

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Antenna Control Stack

Antenna Control Stack

We have completed the final construction and integration of our DX Engineering 8 Circle Receive Array Antenna System for the Low Bands. We built our array to cover 160m, 80m, and 40m some time ago. We also had previously constructed a second entry and grounding system to connect our shack to the new Receive Array System. In this post, I’ll cover the completion of the feedline and control system and the integration of the Receive Array into our shack control systems. The picture above shows the control console for the 8-Circle Receive Array (second box down on the left) as part of the Antenna Control Stack in our shack.

8-Circle Receive Array System Diagram

8-Circle Receive Array System Diagram

The diagram above shows the components in the 8-Circle Receive Array System that we are building. We used all of the components shown above in our installation including the optional Receive Feedline Choke (DXE-RFCC-1) and Receive Preamplifier (DXE-RPA-1).

Array Controller

Array Controller

The first step was to build and install the delay line for the 8-Circle Receive Array System. The delay line ensures proper phasing between the forward and rearward elements in the receive array and is used to create a directional pattern which suppresses noise and unwanted signals from the rear of the array. The delay line is made from a specific length of 75-ohm coax (the same coax that is used in the rest of the system) and is installed in a coil next to the Array Controller. We also terminated the control cable on Array Controller. The control cable carries 12V power for all of the active electronics in the array (12V, 250 ma) and the selection of the control cable must account for the potential voltage drop between the shack and the Array Controller. Our cabling is quite long (approximately 500 ft) so we choose a Heavy Duty Control Cable (DXE-CW8-HD) from DX Engineering. We paralleled spare pairs in the cable with the 16 ga. power and ground wires to ensure that we did not have a significant voltage drop in the control cable.

Feedline Choke

Receive Feedline Choke

The next step was to run a length of 75-ohm coax from the Array Controller to the shack entry point. We choose to install a Receive Feedline Choke in the feedline due to its long length and its installation on the ground (as opposed to buried which would have been impossible in our woods due to roots and rocks). The choke prevents the shield on the feedline from conducting signals from local noise sources or AM radio stations nearby. These problems, if not corrected, would distort the directional pattern of the Receive Array and create higher noise levels in the system. The choke needs to be installed 20-30 ft from the edge of the 8-Circle Receive Array in the feedline. The unit requires a good ground so we mounted it on a 5/8″ x 8 ft ground rod which we drove into the soil. We used a pair of standard ground rod clamps to mount the Receive Feedline Choke on the ground rod. We then secured the feedline and control cables to the ground every 6 ft or so using Metal Anchor Pins from DX Engineering.

Shack Entry Termination

Shack Entry Termination

Once we got the feedline and control cables near the house, pulled them through the PVC conduit we installed to get them across our yard and to the shack entry point. We then terminated them on the ground system and static suppressors that are explained in the article on the construction of our second shack entry system.

Completed Shack Entry

Completed Shack Entry

Finally, we ran the feedline and control cables into the house and to our shack.

DXE Sequencer

DX Engineering Time Variable Sequencer Unit

We use high power on the low bands (1 KW) so the Receive Array’s active electronics must be powered down and the elements grounded when we are transmitting. The Array Controller handles these steps when power is removed from the control cable to the array. To allow for safe switchover of the array between receive and transmit, the power must be removed from the array a few milliseconds before our transmitters and amplifiers switch to transmit. These steps are accomplished via a Sequencer. In a single radio system, a DX Engineering Time Variable Sequencer Unit (shown above) would handle this job including the required time sequenced keying of an associated transceiver and amplifier.

microHAM MK2R+

microHAM MK2R+

Our shack has a total of four transceivers configured as two SO2R operating positions so we used our microHAM MK2R+ SO2R Controller (the unit on top of our Icom IC-9100 Transceiver in the picture above) to control the overall sequencing of our transceivers and amplifiers and the DX Engineering Sequencer to provide fast switching of the power to the Receive Array under control of the MK2R+.

Receive Array Controller

Receive Array Controller

The DX Engineering Sequencer is the last element in the control cable before it terminates on the Receive Array Control unit (shown above). This device uses a rotary switch to control the selection of one of 8 directions that the Receive Array, can be electronically pointed in.

DXE Receive Preamp

DXE Receive Preamp

Due to the length of our feedline, we choose to install a Receive Preamp in the feedline. This unit is installed close to the radio and is powered from the shack’s 13.8V power supply.

75 Ohm To 50 Ohm Transformer

75 Ohm To 50 Ohm Transformer

The final element in the feedline is a 75-ohm to 50-ohm transformer from Wilson Electronics, which converts the 75-ohm feedline from the Receive Array to the 50-ohm impedance at the antenna terminals on our Icom IC-7800. The IC-7800 has a provision to use a separate Receive Antenna, and we configured it to do this by default on the 160m and 80m bands.

With everything in place, we began by testing the Receive Array system with our Transceiver set at a low power level (10 w). Once we verified the operation of the Sequencing System, we turned on the amplifier and verified proper operation a high power. The setup worked perfectly, and the receive Array is much quieter on 160m and 80m than our transmit antennas. This enables one to “hear” weaker signals on these bands much better. The array is also noticeably directional, as expected. I am anxious to operate on the low bands a few evenings (and early mornings) to see how well the system performs, but the early indications are very good.

The following are additional posts covering the other parts of the installation, integration, and testing of our new Low-Band Receive Array.

Fred, AB1OC