Recent Updates Toggle Comment Threads | Keyboard Shortcuts

  • Josh Benson 10:13 pm on March 15, 2012 Permalink | Reply  

    A Cheap Indoor Dipole for 80m-15m 

    Antenna PartsI finally got my hands on an HF transceiver last week.  It’s a gently used IC-735, with CW, SSB, AM, and FM on all bands 160-10 meters with the exception of 60 meters.  It has had the MARS modification done on it, so it will transmit on any frequency between 100 kHz to 30 MHz.  It has a max power output of 100 watts in CW, SSB, and FM modes, and 40 watts in AM.  A handy rig to have for a ham who’s just starting out.  It’s certainly not as spiffy as the brand new DSP rigs with huge LCD displays and power computers under the hood, but there are more than enough features to satisfy the beginning to intermediate operator.  Since I got the rig on the air on March 10th, I’ve had six contacts with my straight key, each in a different state, so I only need 44 more states to get WAS!

    But I’m getting ahead of myself.  The fanciest, most expensive rig on the planet isn’t worth a hill of beans without an antenna to send and receive signals.  I’ve avoided HF for a long time because I assumed the antenna requirements would be too costly in terms of space and money.  I live in a townhouse with no attic, no basement, and a postage stamp yard, and putting up antennas outside is entirely out of the question.  There simply isn’t enough space to string up a full sized dipole indoors for most of the HF bands.  I had the inspiration, however, to try setting up an antenna for 20 meters, which is a popular HF band and should also resonate on 10 meters if designed carefully.

    (More …)

    • Pete Curry 2:08 pm on January 5, 2013 Permalink | Reply

      Hi: I’d like to try this. Does it matter if the base leg is a bit shorter as long as the total length is the same? Thanks, Pete Curry, KA2TTU

    • Josh B 5:18 pm on January 5, 2013 Permalink | Reply

      Hi Pete,
      As far as I can tell the only difference a shorter base leg might make is in making it a bit more directional. As it is setup at my house it’s already much more sensitive along an axis perpendicular to the base leg and in the opposite direction of the two side legs. So for instance the opening of the “C” shape points south and I get much more reception from the north than from any other direction, but I have still made contacts in all other directions as far as 1,000 miles or so. If you get your put up please send me some pictures and let me know how it works!

      –73 de Josh NC4JB

      • Pete Curry 10:49 pm on January 5, 2013 Permalink | Reply

        Thanks, Josh. I’ll let you know how I make out, Pete

    • Pete Curry 9:15 am on January 6, 2013 Permalink | Reply

      Hi Again: In your headline you talk about 80m to 15m coverage with this antenna–with “m“ I assume meaning meters. But in the third paragraph you say you can load it up on all bands between “80 and 18 MHz.” If these numbers are both MHz, shouldn’t the first one be something like 3.5 to 4.0? Thanks, Pete/KA2TTU

      • Josh B. 5:26 pm on September 21, 2017 Permalink | Reply

        Hi Pete, Sorry it took me 4 years to see this! You are correct that is a type and I meant to say 80-17 meters (3-18 MHz). 73s.

    • oh8xat 5:18 am on November 26, 2013 Permalink | Reply

      May this blog post be an example to all those folks out there troubled by a home owners association or landlord. With a CW key and a curious experimenter attitude you can doit.
      (which should be the definition of a radio amateur)

      Too bad all measurement units here limit the use of this post to the imperial colonies.
      But that should not hold anyone back as you can manage with a unit-converter of some sorts.

    • robi 4:29 pm on April 25, 2015 Permalink | Reply

      hello bro!no antenna tuner for use it please

    • Michele 8:13 am on December 2, 2016 Permalink | Reply

      I have read with great interest your (old) post. Do you have updates, experiences, and hints to share? Are you still using such an indoor dipole? Your post sparkled great interest to me.

    • Harry Lythall 3:11 am on April 5, 2017 Permalink | Reply

      It is interesting that few people never look for the benefits on indoor antennas, one ways of escaping the negative effects.

      Yes, an indoor antennas is less efficient and a compromise, but sitting close to the feed point allows you to place an ATU at the feed point itself. This is not possible with a big dipole up a tree in the garden.

      This antenna design can also features trimmed in seconds by rolling up the ends, then unrolling when you change bands.

      I live in apartment with a metal roof balcony, but neigh ours have not noticed two extra plastic drainpipes fixed to the apartment block outside wall. The side lengths of my antenna are outside and hang vertically. I can pull up wire, coil and short to trim, all without the neighbours seeing anything.

      BRING Harry – SM0VPO

    • Harold (K7ILO) 8:58 pm on May 26, 2018 Permalink | Reply

      Soooooooo. Any updates to this design because i just realized that I have everything I need to do this so here we go.

    • Matt 7:51 pm on June 5, 2018 Permalink | Reply

      I’d like to give this a shot! What can I do to make it safe so as to minimize RF exposures.

  • Josh Benson 11:31 am on March 13, 2012 Permalink | Reply  

    No silence is more deafening than that which follows an uncomfortable truth being shouted into the crowd.

  • Josh Benson 2:07 pm on March 4, 2012 Permalink | Reply

    Quick status update, there is a pristine IC-735 HF radio on its way to my house from Maryland as we speak. Should get here in the next week or so. I’m very excited to get on the HF bands and finally make some real contacts. I’m also watching a Packet modem on eBay to try and snag that as well. I got the Amateur Extra class study guide and have worked about halfway through it. Lots of math but almost all of it is identical to the math I’m learning in my AC Analysis class at school, so this jibes well with that. More later when the Icom arrives.

  • Josh Benson 1:59 am on February 29, 2012 Permalink | Reply  

    “For if you [the rulers] suffer your people to be ill-educated, and their manners to be corrupted from their infancy, and then punish them for those crimes to which their first education disposed them, what else is to be concluded from this, but that you first make thieves [and outlaws] and then punish them.”

    Sir Thomas More
  • Josh Benson 2:51 am on February 28, 2012 Permalink | Reply  

    I’m watching several Kenwood TS-140S auctions online. With my tax refund coming soon my plan is to snag one if I can and finally get on HF with some decent power and start making some real contacts.

  • Josh Benson 1:28 am on February 28, 2012 Permalink | Reply  

    “I am aware that many object to the severity of my language; but is there not cause for severity? I will be as harsh as truth, and as uncompromising as justice. On this subject, I do not wish to think, or to speak, or write, with moderation. No! no! Tell a man whose house is on fire to give a moderate alarm; tell him to moderately rescue his wife from the hands of the ravisher; tell the mother to gradually extricate her babe from the fire into which it has fallen; – but urge me not to use moderation in a cause like the present. I am in earnest – I will not equivocate – I will not excuse – I will not retreat a single inch – AND I WILL BE HEARD. The apathy of the people is enough to make every statue leap from its pedestal, and to hasten the resurrection of the dead.”

    William Lloyd Garrison
  • Josh Benson 4:26 am on February 27, 2012 Permalink | Reply
    Tags: , communication, optical, science

    • book auf ra 8:27 am on June 8, 2013 Permalink | Reply

      Today, I went to the beachfront with my children.
      I found a sea shell and gave it to my 4 year old daughter and said
      “You can hear the ocean if you put this to your ear.” She put the shell to her ear and
      screamed. There was a hermit crab inside and it pinched her ear.

      She never wants to go back! LoL I know this is entirely off topic but I had to tell

  • Josh Benson 12:44 am on February 27, 2012 Permalink | Reply  

    I’d like to endeavor to come up with a list of small industries necessary for a sufficient level of commerce to provide for basic consumer needs as well as basic skilled employment, using commonly (and sustainably) found natural resources. I have in mind things like grain mills, skilled wood-crafters and carpenters, glass blowers and glazers, blacksmiths and machinists, brick makers and layers, stone masons, etc. Establishing local cooperatives to learn, perfect, and practice these arts would, I believe, make our economy a lot more durable in times of stress or calamity, and in our particular case would add to our tourist charm. What do you think? Can you think of any other small scale industries that would be useful and beneficial to have in our town or any other?

  • Josh Benson 6:57 pm on February 25, 2012 Permalink | Reply
    Tags: humor, insult, The American South, wit

  • Josh Benson 3:11 pm on February 24, 2012 Permalink | Reply
    Tags: amateur radio satellites space math

Compose new post
Next post/Next comment
Previous post/Previous comment
Show/Hide comments
Go to top
Go to login
Show/Hide help
shift + esc