The Doublet Antenna: The Best Portable Multi-Band Ham Radio Antenna?

Comments · 106

• WE

  @WECB640 · 1 year ago

  Tim, this was excellent.  I'm glad you did this follow-up on the doublet.  My personal experience is to cut the doublet to a "non-resonant" length.  I like to make them a bit shorter than 1/2 wave on the lowest frequency, say 1/2 wave on 30M would be a good starting place.  The reason for this strategy is to provide for less lobes spreading out away from the broadside configuration when using the antenna on its upper harmonics ie. 10M.  The antenna will still tune just fine on 40M   I then adjust the length of balanced line so that I get a compromise impedance that isn't either extremely high or low at the tuner terminals.  Then I connect it all up like you did.  The remote tuner is a great addition to the setup.  At home, I use the same setup but run the balanced line through the wall and direct to the tuner with a balun and only inches of very heavy coax RG-213 to keep losses down and reduce flashovers at QRO level.  I also suggest that anyone using balanced line feed place a balanced RF current meter inline so that they can observe and adjust for equal currents on each side of the line to keep the line from radiating.  MFJ made one (model 835) but you could also use two thermoucouple RF meters, or even two incandescent lamps (one for each side of your balun).  Once balance is adjusted for by lengthening one leg of the doublet, the lamps should be jumpered across for normal operation and allow the full RF to pass.  This is what many of the old timers did.  Hope to work you again soon.  73 OM

  7

• BR

  @brian.7966 · 1 year ago

  I love your enthusiasm, Tim. Well done.

  4

• DO

  @donholman3020 · 6 months ago

  The angle at the Apex is around 59° and 31° at the end of the 33ft leg.:hand-orange-covering-eyes:

  1

• JO

  @johnallsopp8260 · 11 months ago

  Morning Tim, good video on the Doublet, currently using a 100-foot top, 30 feet to the apex, fed with 45 feet of 450 ohm ladder line into a home brew 4:1 current balun. Matches well via the Matt 180 H auto match, and a simple L MATCH into my IC-7100 favourite portable rig. Recently added loading coils to the end of the dipole for 160 meters, left in circuit, the AMU struggles with the match, added rocker switches to the 160-meter section to add another ten feet of element, and WOW, it works. It's all about trial and error; what will work at one location won't work in another. Keep the videos going, Tim. GUD DX de JOHN  G4YDM

  1

• HI

  @hiltopuk · 1 year ago

  Very informative thank you, learned a lot today, even the crab line tip! Always enjoy your videos thanks

  2

• MI

  @MikeN2MAK · 1 year ago

  A doublet is still on the to-do list.

  1

• CO

  @corsavic1 · 1 year ago

  never used one before my next going to try it, very good vid explained loads keep them coming Tim

  1

• G0

  @G0CNN-Ian · 1 year ago

  Enjoyed that. Thanks Tim 👍🏻

  2

• G8

  @g8itb-radio · 1 year ago

  Nice video, well done! I used a doublet antenna with 300 ohm ladder line in my previous house; in this downsized house, a bungalow I’m working on a stealthy antenna for HF and VHF/UHF; much more open sky lines here! <br>But, when visiting friends on the Llyn Peninsula in Gwynedd, I usually use a doublet on their rural smallholding! Anything, bar HF is virtually impossible at that location; I use under 100 watts and even came 1st. In category in a CQWW ssb contest a few years ago, so it worked for me!

  3

• LB

  @LB7VJ · 1 year ago

  You got me hooked at «the best portable antenna» 😂

  1

• M6

  @M6JKW · 1 year ago

  Great video Tim thank you for making and posting 🙂👍

  1

• AN

  @andyM9XTT · 1 year ago

  You were extremely strong on 40 to me tim n sounded great.just had my xl drive on mast delivered too:)

  1