|
New to Ham Radio?
My Profile
Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question
Operating
Contesting
DX Cluster Spots
Propagation
Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers
Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net
|
|
Show all reviews of the PAR Electronics, Inc EF-10/20/40
|
|
You can write your own review
of the PAR Electronics, Inc EF-10/20/40.
|
|
IZ4KBS
|
Rating: 5/5
|
Nov 23, 2009 09:19
|
Send this review to a friend!
|
|
Perfect antenna for QRP/P
|
Time owned: 6 to 12 months
|
|
I have been owning the EF-10/20/40 for almost one year now, but strangely enough I had not yet posted a review here, so high time to catch-up. I'm mainly interested in QRP /P operation on 20m and 40m bands, so this antenna seemed worth a try. And it was! Not that I had major doubts, as I was already an happy owner of a Par EF-SWL, so I knew both the quality of Par products and the outstanding customer service provided by Dale. What I wasn't 100% sure about was whether the actual concept behind end-fed dipoles was really going to work that well, as I expressed on a related thread at http://www.eham.net/forums/QRP/3472 . What I was a bit skeptical about was whether a counterpoise provided mostly through stray capacitances was really enough to make this an efficient TX antenna. Well, in spite of different opinions by very respectable people I must conclude that End-fed dipoles *do* work, and the subject one works especially well. Beside it's excellent electrical properties, the EF-10/20/40 is one of the most field-friendly wire antennas I know of. I simply toss it into a tree with a throwbag and a suitable length of throwline (http://www.newagearbor.com.au/shop/category55_1.htm) and I'm ready to call CQ. A 5 minute job! Not having to bring a tuner is a great plus of Dale's wires. Once the radiator has been cut to freq the first time, in the open and as vertical as possible, SWR does not degrade dramatically even in quite unfavorable setups, say with the wire zig-zagged in a limited space and at a low height, a situation that may occur inside a hotel room and that. In any case I detected that constrained setups never increase the resonating frequencies of the antenna, but they rather cause it to tune lower in freq, with SWR increasing to say 4:1 at the normal operating freqs. One does not need a tuner to recognize that a particular setup is probably a bit too convoluted, and that the wire needs to be shortened a bit to get things straight again. Not wanting to cut the wire (of course!), this simple trick does the job: http://www.strozzi.it/users/carlo/hamradio/epsn4322.html (the diameter of the loop is about 5", not critical). As you see, no tuner and no cuts! You may not get a perfect 1:1 match, but who cares to even measure it ? What you know beforehand is that it will be lower than 4:1, probably 2:1 to 3:1, provided you laid out the wire with a grain of salt with respect to surrounding objects. A 3:1 is still perfectly acceptable, especially when /P and at QRP power levels, most likely with almost no (lossy) feedline in between either. So, beside posting a review, I wanted to provide also some (hopefully) useful tips to the other lucky owners of this excellent product. The EF-10/20/40 build quality is superb, which makes the antenna survive to the severe conditions that may occur when portable (bushes, trees, mud, tangles in the wire, you name them). The shortened length of the radiator with respect to a full-size End-Fedz, as well as not needing a tuner nor extra counterpoise wires make for a very lightweight backpack/portable QRP station! And, last but not least, Dale is a pleasure to deal with and both him and his shop really stand-out from the croud.
|
|
Product is in production.
|
|
Email Subscription
You are not subscribed to this review.
Subscribe!
My Subscriptions
Subscriptions Help
|
If you have any questions, problems, or suggestions about Reviews
please email your Reviews Manager
|
|
|
