Friday, June 13, 2014

A brief overview of my MFJ 1788 loop antenna.

The antenna
Overall I have been very pleased with the purchase of the MFJ 1788 loop antenna. Considering the location I am in and the restrictions of a condo such as.....concrete all around you, other buildings blocking your signal, very small space to put an antenna and power level must be kept low as to not affect the neighbors. After doing considerable searching for the right antenna for this location it boiled down to this antenna. The power I run is 5 watts max and this is not new for me as I have been a QRP op for years now. Below are the reasons why I am pleased with this antenna to be followed by some of the not pleasing things about the antenna.
1. Very small foot print for an antenna that will give you 15m to 40m.
2. The antenna can be used mounted horizontally or vertically.
3. Once you get used to the tuning it's very fast and easy to tune.
4. I covered my antenna with as to keep it low profile and it works no problem with the cover.
5. The antenna remote control can operate either on AC or batteries.
6. Can be mounted on a simple tri-pod.

Some of the draw backs
1. The quality of the antenna is low, I had to make some adjustments to make it work as it should.
2. The band width is narrow and retuning has to be down often.
3. The SWR meter in the remote control unit is not very reliable.
4. Buzzer used to tell you the coarse tuning has finished is VERY hard to hear.
Repairing Cap spacing

On air results with this antenna have been good, with regards to receiving I have been able to hear the Middle East, South Pacific, Europe, South America and of coarse North America. Now hearing a station and contacting the station is another ball of wax. With my power restrictions I have made some very satisfying contacts. My modest signal has made it into South America, all parts of Europe, Iceland and Africa so far. There are two Loop antennas that MFJ makes and if I was to make the choice again I would had gone with the MFJ 1786 as it covers 10m to 30m. I have found with this antenna there is no way to tune it below 15m. The characteristic of the tuning capacitor will not allow it. I have read the MFJ 1788 is like a wet noodle on 40m and it's true I have not been able to make it into the U.S. The MFJ 1786 would had been a better choice with more band opportunities.   


  1. Have the majority of your QRP contacts been made on CW? Do you use digital or SSB, ever?

    73 de VE3LBL

    1. Good afternoon Berry, all the contacts have been made with CW and up to this point I have been thinking about getting back into the digi modes. I will set up my Elecraft KX3 for the digi modes. The Loop antenna would be great for this as you really don't have to worry about frequency changes and having to readjust the loop.

  2. Nice to hear that a small loop works well for you in a condo balcony setup with 5 watts CW. I'm looking to do something similar with a homebrew loop. A few questions for you:

    1. Do you find that horizontal or vertical orientation is better for you?

    2. What is the makeup of the front railing/front wall of your balcony? Is it a solid concrete wall? Or is it some sort of an aluminum or iron grill? Also, what is the makeup of the condo building itself? Steel-reinforced concrete?

    3. From your photo I understand that your antenna is mounted completely inside the confines of your balcony (not stuck out over the edge). Regarding the mounting height of the antenna relative to the balcony's front railing/wall: Is the loop mounted higher than the front railing/wall so that it has a clear line-of-sight to the horizon, or is the loop mounted in a lower (stealth) position below the front railing/wall and blocking its line-of-sight to the horizon?

    4. How sensitive is the loop to its surroundings? For example, your photo shows the loop right next to a glass/metal partition. If you move the loop say 1 meter farther away from this partition, do the tuning and SWR change drastically, or just a little?

    5. Any problems with your signal getting into neighbors' equipment? For example, unshielded and cheap computer speakers (that tend to rectify/amplify any nearby RF), TVI, etc.?

    6. On what floor is your condo?

    Thanks for any advice!

    1. Thanks for stopping by the blog and taking the time to comment, sorry for not getting back to you sooner but your comment was put in the spam filter for some reason. So to answer your questions....
      1. I have not tried the loop in the vertical position for the reason it would not be able to look like a patio table under the cover.
      2. The front of the balcony is glass with an aluminum railing. The wall to the right is a glass divider from our neighbour beside us and to the left it is a solid concrete wall. The condo is concrete with steel-reinforcement a.
      3. Yes the antenna is within the confines of the balcony and not over or close to the edge. It is just above the level of the railing of the balcony. I just have a clear line of sight to the south ( the direction we are facing)
      4. I try to keep the antenna close the to centre of the balcony and yes it is very sensitive to it's surrounds and the SWR can rise dramatically. At first I had to move the antenna around to get the best position. I have marks on
      the floor of the balcony to show where the antenna should be positioned.
      5. I have up to this point had no issues (that I know of) with RFI but I only use digi modes and CW at 5 watts max.
      6. I am on the 6th floor of the condo.
      I hope this answers your questions but if you have more please feel free to email me direct at
      73, Mike

    2. Thanks for the informative reply! I'm encouraged by your success and will try horizontal mounting similar to your setup (once I've finished building my loop).

      FYI, here's another blog that contains some good ideas for a stealth loop installation: .

    3. Always glad to help and again if you have anymore questions pop up just email. Thanks for the link and when I get some spare time I am going to check it out.
      73, Mike