Summer is the time of year that many of us work on our antennas and improve our stations. Anita AB1QB and I did both of these things at our QTH this summer.
Removing Lower SteppIR Yagi From Tower
Our SteppIR DB36 Yagis were due for some maintenance so we took them off our tower. A special thanks to all the members of the Nashua Area Radio Club who helped us remove, recondition and reinstall our antennas! Matt Strelow, KC1XX of XX Towers, and Andrew Toth provided equipment and know-how to safely remove our two large SteppIR DB36 Yagis with help from the rest of us.
Lowering Antenna With Electric Winch
The SteppIR DB36 Yagis weigh almost 200 lbs each and Matt made good use of his electric winch to lower them.
Antenna Coming Down The Tram Line
The picture above shows the lower antenna coming off the tower. We used a Tram Line system to lower both antennas to the ground so that we could rebuild them.
SteppIR DB36 Antenna On The Ground
The SteppIR DB36 Yagis are quite large. They have 36 ft booms and the driven elements are almost 50 ft from tip to tip! They completely fill up our backyard when they are both off the tower.
Element Pole Sun Damage
The rebuild process began with a careful inspection of both antennas. They were both in good overall condition with some sun damage to the paint on the fiberglass element poles.
Disassembled SteppIR DB36
We removed all the element tubes and sweeps from both antennas for rebuilding. The picture above shows the disassembled upper antenna.
Reconditioned Stepper Motors Installed
All four Stepper motors on both antenna were replaced. These motors move metal tapes inside hollow element tubes to adjust the length of each antenna’s 4 movable elements. These adjustments are done automatically by controllers in our shack which receive frequency information from the radios which are connected to each antenna.
Reconditioned Element Sweep Poles
All of the element housing poles were cleaned, prepped and painted with a UV resistant clear coat to protect them from further sun damage. The poles cleaned up like new.
New Element Sweeps Ready For Installation
The assembly of all the new element sweep tubes (shown above) was done next. Each antenna has six sweeps.
Element Pole Preparation
The end of each element pole must be prepped with a tape system which ensures that the poles are seated properly, sealed to and firmly attached to the sweeps. This process and the associated assembly and tightening of the element couplers was the most time-consuming step in the rebuild process as it had to be repeated a total of 24 times.
Rebuilt Element Assembly
Here’s a picture of one of the rebuilt element tube assemblies. The ropes support the element tubes and keep them aligned when the antenna is up in the air. These elements are attached to the antenna motors with couplers and clamps.
SteppIR DB36 Yagi – Rebuild Complete
The picture above shows the lower antenna with all the element tubes reattached. There is quite a bit of additional prep work associated with adjusting all the supports and taping all the exposed areas of the antennas which are susceptible to sun damage. Also, all the electrical wiring on the antenna must be checked to ensure good electrical connections and good overall condition of the wiring.
Ground Test Setup
The final step in rebuilding the antennas is to test their operation on the ground. This ground test is done to ensure that all the motors are working correctly and that the element tapes move smoothly inside the rebuilt element tubes.
Ground Test Results
Another important part of the antenna Ground Test is to confirm that the antennas have a consistent resonant frequency and SWR on all bands. The resonant frequencies and SWR levels are far from those that would be measured when the antennas are on the tower at operating height. The idea here is to confirm that a resonance exists and that its frequency and SWR readings are repeatable as the antenna is adjusted to different bands.
With both antennas rebuilt, it was time for Matt and Andrew to return and, with help from folks from our club, reinstall the rebuilt antennas on our tower. The video above shows this process. It is quite something to see! The installation took about 3 1/2 hours.
Updated SteppIR Controllers
The last step in the SteppIR DB36 rebuild process was to install the latest firmware in the associated SDA100 Antenna Controllers. There are some integration issues between the updated SteppIR Firmware and our microHAM system but we are getting those worked out with help from the folks at both SteppIR and microHAM.
Icom IC-7851 With Display Monitor
I recently had a major birthday milestone and Anita surprised me with a new radio – an Icom IC-7851. This radio is an upgrade/replacement for our Icom IC-7800. While the two radios are quite similar in their operation and interfaces, I did not want to install the IC-7851 until the SteppIR antennas were reinstalled and all of their upgrades were working properly with our current radios. With the antennas done, it was the finally time to install the new radio!
Icom C-7851 Transceiver
The Icom IC-7851 has several important performance upgrades. The most impactful one is a new low-phase noise oscillator which significantly improves RMDR performance compared to the IC-7800. The IC-7851 is in the top-tier of Transceivers in Sherwood Engineering’s tests. The receivers in the IC-7851 are very quiet, have excellent Dynamic Range and perform great in when close-in interference is present.
Icom IC-7851 Display Monitor
The Icom IC-7851 has a higher resolution and faster display. It also supports higher resolution external monitors so we installed am upgraded display monitor along with the new radio. The IC-7851 has a number of new networking features and supports stand-alone remote operation over a LAN and the Internet. We are planning to use these capabilities to add a second remote operating gateway to our station. More on this in a future article.
The combination of the rebuilt antennas and the new IC-7851 Transceiver has our station performing better than ever. The antennas are working as well or better than when they were new and the IC-7851 has significantly better receive performance compared to its predecessor and is a pleasure to use.
We will be hosting the ARRL Rookie Roundup RTTY contest for our club members who have received their first license in the last 3 years next weekend and we’re going to use the new radio and rebuilt antennas for the contest.
This project was completed in a little over two weeks and was a lot of work. I could not have done the project without the help of the many folks in the Nashua Area Radio Club. Again, a big Thank You to all the folks in our club who helped me with this project! I hope that many of you will be able to find some time to operate from our upgraded station.
73,
Fred, AB1OC
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Hi Fred,
Very nice photos and text, quite informative. Thank you for creating them to show your antenna project.
In 2008, Matt and Andrew did a site survey, gave me a formal quote, and upon my acceptance, they dug the holes for the tower and the 3 “pads” for the 2-level guy wires. I had to “drop” a lot of trees, to create a clearing in the woods for the tower and the guy wires. They had the concrete guy stop by, arranged some long troughs to steer the concrete into the tower’s base hole, and the 3 “Pads” for the guy wires. They put up a 90-ft.Rohn 55G tower, using their electric winch for each section. They built the M2 8-el. Log Periodic antenna (40M thru 10M), and mounted it + the M2 Rotor, on the tower. They attached the hard-line and rotor cables, and directed them toward the house 400-ft. away. Where the cables exited the woods, Matt dug a nice trench and buried the cables as they crossed the lawn, and had them “pop up” from the trench just outside the shack window.
Last Fall, Andrew installed an 80M Sloper fed at the top of the tower, with a 67-ft. wire directed toward the ground at a 45-deg angle, and pointing toward Europe. This Sloper made all the difference. I was having frequent QSO’s on 80M SSB with European stations as early as 4 PM, local time, in the winter. Would often get signal reports in the evenings from Europe of 59+10dB–>+20dB. Quickly went from 90 countries worked to 140 countries worked and 130 confirmed, and earned my 80M DXCC. And because I had already been “pre-approved” with DXCC via LoTW confirmations on 40M, 30M, 20M, 17M, 15M, 12M, & 10M, getting 80M DXCC enabled me to earn the 5-Band DXCC + the 3 Endorsement Stickers for 30M + 17M + 12 M.
In September, Andrew’s going to put up a 160M Sloper for me. A 45-deg slope is impossible for a 135-ft Sloper, fed at 85-ft. It’ll be about a 38-deg slope from top of the tower to where it meets the ground. On 160M, I have 46 countries worked and 29 confirmed. Going to make a big push this winter, and try for 160M DXCC, which if granted will enable me to get the prestigious 9-Band DXCC award.
I hear you often working DX, but not sure if you want to take a call from a local for a quick chLet me know. I work a lot of CW DX; please call me anytime.
73 & Good DX, Gary W1EBM Old Milford Road (top of the hill – #132) in Brookline. QTH is 750-ft ASL, and 350-ft Above Average Terrain (In the winter, rain at the Brookline Village Store very often is snow, in our “micro-climate” 350-ft higher, at the top of the hill)
Can see the Pru and the Hancock Tower from the top of the tower…on a clear day…40 miles away.
Date: Mon, 15 Aug 2016 02:25:10 +0000 To: gary_smetana@hotmail.com
Very interesting and timely information, being located on Borneo (9M8) I shall ensure that all the element tubes on my new 18E receive an adequate coating of UV resistant clear paint before it goes up.
Thank you for sharing so much useful information on you website.
73
JG
9M8/VA2TWT
QTH: OJ74AM