Wednesday, May 2, 2012

The W3EDP Antenna, Deployed!

I recently made a series of videos about deploying the W3EDP antenna:

In part 1 I show you the rolled up, fresh out of storage W3EDP antenna Notice how compact it is. This antenna can be stored anywhere! It's best to watch the playlist "W3EDP" on my youtube channel. The videos are short, and it was my intention to stitch them all together into a short movie, but I had to choose between learning a new program for editing video, or publishing the information.

I deployed the antenna on last Sunday afternoon (April 29th), and it's still up. I've been doing some testing between it and my 40m dipole. I use an MFJ-941B versatuner to tune both antennas, even though the 40m dipole should be resonant on 40m.
Both antennas perform well on 40m.
Both antennas perform well on 20m.
When the tuner tunes the W3EDP antenna, I can use the 40m dipole. The dipole will have an SWR of 1.5:1.
Tuning the W3EDP on 40 and 20 is fairly sharp. Tuning the dipole is sharper on 20 than 40, but not nearly as sharp as the W3EDP.
Last night I tried both antennas out on 75m. This is where the most difference was noticeable. The 40m dipole has a hard time tuning up on 75 with the Mighty Fine Junk tuner. I've noticed some arcing at full power (100w out of a Swan 100MX) when I try to tune up. When it does get tuned up, the bandwidth is very narrow, around 30KHz, and then you have to retune. As a result, I don't get on 75 very often. With the W3EDP, it's a different story! The traditional way to use a W3EDP on 75/80m is to detach the 17' counterpoise, and attach a longer wire and use it as a 1/4 wave vertical with one radial cut 1/4 wave for 75/80m.  I've done that when I had an FT-817, and was able to check into the CARF net on 75m with 5 watts. That W3EDP had a more vertical orientation than the one I have deployed now. I worked the antenna here against station ground. Station ground at KG4GVL is an 8' groundrod driven into the ground. I need to get some more copper planted. Regardless, results were satisfactory. Even when the 'vertical' part is up in a vee, with the highest point no more than 20' in the air, and the far end about 4' off the ground, performance is determinatively better than the dipole. Tuning is not as touchy (even if it is somewhat touchy), and signal levels are noticably louder. I expect performance to improve when I install more radials. I haven't tried 10 or 15m on the W3EDP yet, perhaps later this week. Doing comparisons is tough with only 1 tuner that can handle 100w because when I switch antennas I have to retune on all the other bands but 40. Same tuner settings work on 40m because I'm willing to live with a 1.5:1 SWR.

Stay tuned for more comparisons! I'll be QRV when I get home from work tonight.
GB Hoyt


P. Thomson said...

You might find the tuning more narrow with more ground radials... it will decrease the ground resistance and increase the "Q" of the system. But if the tuner can handle the lower impedance, you should get better signals. 72 DE KA2QPG

GB Hoyt said...

Thank you for your input! I've heard that can happen. I would also like to know what exactly is happening to the power I radiate. I have a highly calibrated (rolls eyes) Radio Shack brand field strength/SWR meter that I leave on the shelf in "Field Strength mode" near my feedlines. I've seen some interesting things happen according to that meter using the W3EDP! It definitely warrants further experimentation.