Here I review a cobweb antenna offering from MFJ Enterprises, having recently installed said model at my own residence with the help of a good friend from the Gippsland Gate Radio & Electronics Club which is located in Cranbourne, Victoria, Australia. Said friend was most kind enough to spend more than just a few hours in setting up the whole thing and then tuning it so that the whole antenna was in good working order. I therefore detail below my ensuing experiences over the following two weeks from then and my overall satisfaction with this kit.

It needs to be said; for the amount I paid for this antenna from DX Engineering, minus the horrific postage charges that ensue with international shipping and handling, alas, I am exceedingly happy with the performance of this antenna kit. Not only is it quite the compact dipole but I have been receiving signals all the way from Great Britain with good reliability whilst making repeated, confirmed and logged QSOs over FT8 with others all the way from Canada and the Eastern seaboard of the United States with only 40 watts PEP of transmission power. This is the equivalent distance of approximately ~16,000 km if you take the short path! I do admit to using a bit more power than necessary to transmit with though at times, so there is some laziness on my part!

  • IMG_20180814_090405
  • IMG_20180824_151628
  • IMG_20180824_151634
  • IMG_20180824_161137
  • IMG_20180825_134539
  • IMG_20180825_134921

The antenna's bandwidth is decent although I do wish it was a bit better in that regard, but it is very much usable in all of the common HF bands outlaid by the Australian Standard License, of which is the grade I possess at the time of writing this article. There is an upgrade kit available (MFJ-1836HK34) that adds the 30 and 40 meter bands, so I do plan on purchasing and installing that in the near future. I will also be writing about said upgrade kit on this website as well. But otherwise, if you stay within the optimum conditions of the antenna and provided that you have tuned up everything correctly with an antenna analyzer beforehand, you can expect an SWR below 1.5:1 without the need of an external (automatic) antenna tuner.

One thing that needs to be mentioned for those aspiring to use this antenna is that for me at least, is that a ground/earth stake dedicated to my ham shack had to be installed as otherwise, I was experiencing a number of RFI issues throughout my house. These ranged from the NBN VDSL2 modem/router combo reliably disconnecting whenever transmitting over 40 watts PEP with SSB to even getting a minor RF burn at one point. So it is something to watch out for.

  • IMG_20180913_115648

Lastly, a shout-out to my mate, Ian, from GGREC for all the assistance he provided in getting this antenna setup and installed :) Without him, I would've spent many hundreds of dollars on organizing a contractor to install this antenna who themselves would likely not know what to do when presented with amateur radio equipment and guidelines, instead only being used to the more common television antennas. I'm very new to this hobby and also don't know what I'm doing myself, so the assistance that Ian provided was invaluable!

2018/09/22: As of last night, I have installed a 1:1 5kW Dual Core Isolation Balun (model #1115di) from Balun-Designs and it has provided considerable performance benefit. My brother's notebook is a major source of EMI on the HF bands within the house, particularly on the 20 meter band, and this balun reduced the noise down from a continuous S7-8 towards S4-5 which is quite the improvement! Harsh, digital, tonal noise is not as noticeable either with the unchanging, CW-like noise having once penetrated many of the frequencies on the HF bands. Now it can only be faintly heard most of the time. Many of the pictures provided below were from the Balun-Designs website, especially the graphs. The one of my father on the roof belongs to me though. He kindly helped me install the balun onto the antenna.

  • DSC_0105__86267.1456660199
  • IMG_20180921_165959
  • model-1115d-choking
  • model-1115d-scan

The effect caused by this balun is explained in this video below, which was shared with me by a close friend. It is why a good balun is so crucial to a balanced antenna.

Attachments:
Download this file (mfj-1836h.pdf)MFJ-1836H Manual[Instruction manual for the MFJ-1836H cobweb antenna.]459 kB
Download this file (Model 1115di.pdf)Model 1115di[Dual Core Isolation Balun, 1.5-54 MHz, 5kW]461 kB

Comments (0)

There are no comments posted here yet

Leave your comments

  1. Posting comment as a guest.
0 Characters
Attachments (0 / 3)
Share Your Location

Newsletter


Created by PA4RM