Slim Jim vs. Traditional J-pole Antenna

Measured gain of SlimJIM and J-Pole

Real measurements of a Slim Jim antenna and traditional j-pole antenna reveal the truth about their respective gain and pattern.

Have your J-Pole and ground it too

1.06 GHz Test J-Pole Antenna

Tame the predictable mast currents found in any j-pole antenna grounding conductive mast using a simple stub. Shown is empirical evidence why this is a problem and a very simple solution all future grounded j-pole antennas should incorporate.

Build this Vertical Portable HF Antenna

The Asymmetrical Hatted Vertical Dipole (AHVD) prototype is an easy to build, portable alternative to other freestanding vertical HF antennas such as the Buddipole.

Asy Hat Vertical Dipole

Three views showing a how a planed vertical need not always be the classic 1/4 wave monopole.

We re-introduce the theory and origins of Cebik’s (W4RNL) Asymmetrical Hatted Vertical Dipole (AHVD) antenna with the hope to facilitate a vertical polarization portable 20-10m aerial for portable operations.

40m Mastless NVIS Antenna

Yet another 40m Cloud Burner design featuring a folded dipole driven element plus one reflector wire to facilitate 40m NVIS contacts without need of a tall mast. The design uses electric fence posts for support and needs no balun.

Superbowl HDTV Antenna

Build the venerable Hoverman TV antenna and watch digital broadcast high definition HDTV television this weekend. This version of a HDTV antenna uses amateur radio antenna building techniques to make a lightweight structure.

Copper 6m Coplanar LFA Yagi-Uda

The Coplanar Loop Fed Array (LFA) Yagi-Uda design from G0KSC provides an excellent design foundation for an all copper version of a 3 element 6m balunless beam with superior front to back performance. Shown are comparisons between model simulations and prototype measurements.

Coplanar Loop Fed Array LFA Yagi-Uda Antenna

The clever application of the folded dipole loop, computer science iteration techniques and NEC simulation to Yagi-Uda design results in a panoply of practical planar Loop Fed Array, LFA Yagi antenna recipes.

Improving the Super-J

Full view of various Collinear J-Poles

The traditional collinear J-Pole, aka Super-J, improves the basic J-Pole. Are further improvements possible? By replacing the phasing stub with a simple coil, the answer is yes. The result is the Collinear J-Pole.

EFHW LNR Precision EF-10/20/40MKII Examination

The background and details of the LNR (Par Electronics) EF-10/20/40 end fed half-wave multi-band portable HF antenna. Come see what’s inside the mysterious “black box.”

Antenna Measurements on Taurus 2m Whip

Return Loss and SWR measurements of a permanent 2m whip installation mid-roof of a Ford Taurus. The effect of doors is shown.

5 HF Band Hex Beam on Six Meters

I am preparing for the Virginia QSO Party and want to add an alternative 20 meter solution for my 43 foot vertical plus get better 15 and 10 meter coverage; I have been working plenty of 15 meter contacts with the 43 foot vertical so I know that band is open. Plus you never know if the sunspots might give us some 10 meter fun too 😉

So…

I have been eagerly absorbing all there is to know about the hex beam style of HF antennas.

If you are the least bit interested in building or buying your own hex beam a must read web site is the G3TXQ study of the hex beam…

Read more5 HF Band Hex Beam on Six Meters

Hiking, Hams and Hills – Station #6 of the AT Golden Packet

Virginia hikers and hams supported the White Rock Cliffs (Station #6) of the first Annual Golden Packet Event.

Summarized, we were trying to set up APRS relay stations up and down the east coast to cover and service all points along the Appalachian Trail and surrounding areas. Some RF link analysis was performed and is available for viewing at AT_Golden_Packet_Event using the remarkable Radio Mobile program and A LOT of SRTM elevation data.

Of the fourteen stations planned several points were accessible only by foot. The White Rock Cliffs station was no exception.

Read moreHiking, Hams and Hills – Station #6 of the AT Golden Packet

Collinear 5/8 wave J-Pole vs. Collinear 1/2 wave J-Pole EZNEC Shootout

While planning for a ham radio hike into the mountains to support the Appalachian Trail Golden Packet exercise, I asked my club members for ideas about a good portable 2 meter antenna.

One response included a link to this web page showcasing a collinear J-Pole antenna using two 5/8ths wave antenna elements.

Read moreCollinear 5/8 wave J-Pole vs. Collinear 1/2 wave J-Pole EZNEC Shootout

NVIS 80m with 160m Full Wave Loop is less than ideal

As my local club in northern Virginia prepares for the March Virginia QSO Party many questions are asked about how best to take full advantage of Near Vertical Incident Skywave (NVIS) communications so critical to maximizing contacts on HF within the state.

In particular one member has a magnificent full wave 160 meter loop up around 50 feet or so. He is contemplating using it for NVIS on 80 meters. He desires to lower it to about 15 feet to improve the NVIS characteristics.

It is true lowering a dipole will focus more energy straight up while reducing the energy towards the horizon. This is a tried and true technique on 80 and sometimes 40 meter NVIS and offers a potential added benefit of less sensitivity to far away thunderstorm noise. This is a method of diminishing returns; Lowering the antenna favors the sky more, but the overall gain is reduced. In other words, less signal is focused in a better NVIS favoring pattern.

Full wave loops are quite different as this EZNEC simulation suggests. Here is a simple four sided loop with 128 foot sides and fed near one corner – just like my friend’s 160 meter loop.

Read moreNVIS 80m with 160m Full Wave Loop is less than ideal

BigIR vs. 43 Foot Antenna EZNEC Shootout Conclusions

We have looked at the 43 foot antenna available from DX Engineering and Zero Five alongside the BigIR product from SteppIR. In addition, the BigIR was simulated using the optional 80 meter coil.

Both antenna types approach the vertical HF antenna problem with unique solutions.

Read moreBigIR vs. 43 Foot Antenna EZNEC Shootout Conclusions

BigIR vs. 43 Foot Vertical Antenna @ 80 meters EZNEC Shootout

As we continue our EZNEC simulation research for the 43 foot and BigIR antennas we finally are looking into the 80 meter band.

Read moreBigIR vs. 43 Foot Vertical Antenna @ 80 meters EZNEC Shootout

BigIR vs. 43 Foot Vertical Antenna @ 40 meters EZNEC Shootout

Continuing our NEC Shootout between the 43 foot vertical available from DX Engineering or Zero Five and the adjustable height BigIR antenna available from SteppIR antennas we now analyze them in the 40 meter band.

Read moreBigIR vs. 43 Foot Vertical Antenna @ 40 meters EZNEC Shootout