I decided to post a copy of the email I wrote to Doug Hendricks, one of the founders of the legendary Norcal QRP Club, as he had given me advice on how to build a Norcal Doublet Antenna. I used it for just under one year (2002-03) as my only antenna, up less than 14 feet from the ground in the attic of a duplex I rented in Santa Clara, CA.
From: Ron Chester
To: Doug Hendricks, KI6DS
Sent: Thursday, March 06, 2003 12:37 PM
Subject: NorCal Doublet
I hope you get this. I got your addresses from the QRP-L archives on messages you had posted to the list in February.
You may not recall, but ages ago I asked you for details on how to construct a NorCal Doublet. I had been using a full-size 80m dipole in the vacant lot next to my rented duplex with very good results. But then the owner of the lot started constructing two new homes in the lot, so the dipole had to come down. This left me with nothing but a front yard that is about 15 feet deep for my antenna farm.
I tried Vern's MP-1 inside my little house for a while. I made contacts, but it was rough at times, and I didn't like having to get up to retune the coil every time I changed bands, especially since I didn't have the motorized version of his tuning coil.
So I finally decided to give the NorCal doublet a try in my attic. I went to HSC, bought the ribbon cable and cut it as specified. I climbed up into the attic and secured the center point at the peak of the attic, which is just 13 feet 9 inches above ground, as this is a one-story duplex. Because of the slope of the roof and the overall size of the attic, it was only possible to keep the antenna wire at that height for about 8 feet on either side of the center, before the slope of the roof forced the wire lower, to a minimum height of 10 feet above ground at the ends. It was also necessary to bend the antenna into a zig-zag Z shape overall, as the attic is much too short for a full 44 foot run. At the ends I couldn't squeeze into the narrow space between the roof and the floor of the attic to secure the ends of the antenna, so I had to simply toss them onto the floor of the attic as far out as possible. Certainly not an ideal installation, but I was hopeful that it might net me some contacts. It is hard to imagine how dirty one can become while crawling around in an attic that has 40-50 years of accumulated dirt!
My first contact on the attic doublet was on 6 February 2002, just over one year ago. I've used a large variety of rigs with the antenna, including QRP rigs like the Elecraft K2, DSW-40, DSW-30, OHR-40, OHR-20, OHR-400, as well as my larger rigs, such as an Icom 751 and Ten Tec Century 21, Triton IV and Corsair. I have tuned it with an Icom AT-100 autotuner, but mostly I've manually tuned it with a Decca KW109 supermatch tuner. I'm old fashioned and like to turn the knobs on the old KW109. I'm able to get a very low SWR on all hf bands from 40m through 10m. I even used it one day on 6 meters, using the Yaesu FT-690RII rig at 10 watts into an MFJ 906 6m tuner. Best DX on 6 meters that day was 900 miles to Albuquerque and 700 miles to Arizona.
The performance isn't all that good on 40m, but it seems to work very well on the rest of the hf bands.
On March 15 I will be moving to a new home which is on 1/3 acre, where I will finally have room for more of a real antenna farm. So I decided to add up my results using the NorCal Doublet before I leave this duplex. I should make it clear that because of work and such I have not been able to spend a whole lot of time on the air, but I have been able to play around in some of the contests over the last year, such as the CQWW DX and ARRL DX contests. I have not had the time to avidly chase DX every day or even every month, but I tried to maximize the results in my limited time by operating in contests when I could.
I have limited most of my operating to QRP power levels, but not always. Especially on SSB I have sometimes raised the power to 50 to 75 watts output to make a contact.
My best miles per watt QSO's were on 2/17/02 when I worked Japan using the K2 with 373 milliwatts on 15 meters cw and 100 milliwatts on 20 meters cw.
Overall I worked 72 DXCC countries, with 45 of these being at QRP levels, mostly CW. I worked all continents QRP with CW and all but Asia with SSB. I worked China on SSB at 50 watts to complete the WAC SSB. I did WAC QRP on 10 meters alone, as well as on 20 meters. I worked 29 countries QRP on 15 meters, but never worked Africa QRP on that band, so I didn't do WAC QRP on 15.
I've worked all states on cw and 48 states on SSB, missing only Nevada and Utah on phone. The CW WAS is at QRP levels, but many of the SSB contacts were at higher power, no more than 75 watts.
The only antenna I had during this period was the NorCal zig-zag doublet in the attic. I'm sure with more time I would eventually work DXCC with the antenna. But when I get to the new QTH I will undoubtedly want to put up larger and higher antennas.
The final test of the antenna came in a cw competition sponsored by the Palo Alto ham club, PAARA. At the club meeting on Nov. 1, 2002 the club president proposed a game to see who could work all states first, using cw only. The idea was to encourage cw operation and the prize for the winner was to be the new NorCal 30 kit, once it comes out.
Well since the very next day was the ARRL Sweepstakes CW contest, I decided to give it a try. That weekend I worked 41 states, all at 5 watts. I then picked up Oregon at 5w in a Fox Hunt a few days later. Then in the ARRL 10 meter contest in December I picked up Maine, Arkansas, Georgia, South Carolina, and Delaware at 5 watts, plus Mississippi and Nevada at 65 watts. The final state of Alabama was worked with 70 watts during the first hour of the North America QSO Party on January 11, 2003. So I completed the CW WAS in 71 days from the start of the game and was declared the winner!! Only three of the states in this game were worked with more than 5 watts. I had previously worked those states at QRP levels on the antenna.
For the WAS competition I only used the Ten Tec Corsair rig (which I picked up at the Livermore swap meet for $200), the KW109 tuner, a Logikey K3 keyer, Schurr Profi paddles and the NorCal zig-zag doublet in the attic.
Now I anxiously await the release of the NorCal 30, so I can build it and really exercise my bragging rights at the PAARA meetings.
Anyway, I thought you might like to know how I did with this antenna. It's not the best antenna I've ever used, but it might have been the best I could do under the space limitations I had, and it certainly made it possible for me to get on the air and make a lot of contacts, when I might not have otherwise. That's what really matters.
Thanks for your advice and help with the antenna!