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The test setup

I was out today once again with my portable operations but this time there was no on air time it was time to test and decide. I went out with my MFJ antenna analyzer, mobile whip antennas and various lengths of counter poise. I wanted to see where my 20m mobile whip antenna was resonant and using the MFJ analyzer was the easiest way of doing this. The counter poise for 20m I started with was 17.5 feet long and the SWR was not showing it was resonant in the CW portion of the band but in the SSB section. So I found I have to lengthen the counter poise to 30 feet to get the SWR to 1.2:1 in the CW portion of 20m. This got me to thinking if the mobile whip was the way to go, I did have these antennas hanging around and I wanted to give them a go to see what results I would get. They are still very useful to me when I operate portable mobile from the car and they preform very well in that situation. I wanted to try the whip  antenna as I felt it would be a very small footprint of an antenna but with a counter poise of 30 feet the footprint is larger than I would like. From most of my blog reading about portable trail operation, NPOTA operations and just plan old out in the park for the day operation hands down most of the time the antenna of choice was one of LNR's par end fed antenna's.   I have looked over the antennas at LNR Precisions site and not sure yet which antenna to get, I am leaning toward the EF-20 as it's not as long (33') as say the other models. I'm really not going to use 40m and I figure (but not sure) I can use the Elecraft KX3's tuner to operate 15 and 10M?? Any feedback about this antenna or others would be appreciated.

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.   

LP-100 reading

I was on the air the other day using the MFJ loop and as I was trying to tune to the lowest SWR reading I noticed an odd thing happening! Available to me at the station are 3 separate points to view the SWR. I have the SWR reading on the K3, the LP-100 and the MFJ remote control for the loop antenna. While tuning the loop antenna I was able to get an SWR of 1.5.1 on 20m with the K3's meter this is a very decent reading. I had the same reading on the MFJ remote unit but the LP-100 was showing 2.08 SWR??? The way the meters read the SWR are as follows.....the K3 right at the radio, then the LP-100 and then the MFJ remote unit. Oh and in case you are wondering if I am SWR meter crazy, I have the LP-100 in the game plan as it also reads very accurate output power and when operating QRPp it comes in very handy. . as for the MFJ remote that just comes with the antenna package and is really used to adjust the antenna and I really don't rely on it's SWR meter. I have heard and read in the past that the remote MFJ meter should not be relied on to much. ANYWAY.............I am getting this odd reading on the LP-100 and it is on all bands that I get a differing reading from the other SWR meters. First thing that came to mind was faulty coax or faulty

K3 meter

LP-100. I bypassed the LP-100 ( I removed the LP-100 and attached the two PL-259 using a SO-259 coupling) using all the same coax that fed the LP-100 and there was no problem. I then setup the LP-100 on it's own, meaning out the K3 through the LP-100 into a dummy load and there was a perfect match. Then I simply removed the SO-259 coupling and added the LP-100 again....there was the funny SWR again. Not sure what is going on here. In my trouble shooting I tried the LP-100 on it's own into a dummy load and it worked fine. I then used all the same coax cables and bypassing the LP- 100 and all was fine. Therefore LP-100 is fine and cables are good??? Not sure what is going on here.

Time to repair the control box.

It seems that almost all the bugs have been ironed out with the MFJ 1788 loop antenna. I sure have had an adventure with the unit but things seem to be on the upswing now. Some of the indicators the MFJ loop gives you when your match is good are High noise level meaning you are in the ball park. The SWR meters on the control box that visually tell you the SWR is good. Finally there is a tone that comes from within the control box when you are auto tuning the loop. As far as I am concerned this tone is only within the range of our cat Oliver's hearing. UNTIL........one day when I was tuning the loop in auto mode and all was going well until Julie tapped me on the headphones saying "can you not hear that ANNOYING sound!! I took my headphones off and still nothing it was not until I put my ear right up to the MFJ control box could I hear the tone. WOW my hearing must be way off  as Julie said it was very noticeable to her in the living room and to add insult to injury she also heard it over the TV. Needless to say this event happened a few more times and

Ready to remove switch

it seemed apparent that it was time to cut the wires to this speaker. While I was in there I also had to replace a switch that controls the range of the watt meter on the MFJ control head. The original switch did not work very well at all and MFJ was kind enough to send me 3 extra ones. Cutting the wires to the speaker (I could never hear) was very fast and easy but for this switch to be changed most of the unit would have to be taken apart it seemed. Once I was ready to remove the old switch and replace it with the new one it was very easy........having said "easy" it means that with the right tools it was easy. I used the Hakko 808 de-soldering gun and believe me this unit makes very easy work of removing the old solder. To the point were the defective switch just falls out of the board. In the past I have used the hand held de-soldering pumps and the wicks as well but nothing works as well as this unit. The solder station I have is the Weller WES 51 and it has served me well for many years and you can change out the tips for various jobs you want to do. So with the wires cut to the speaker and the new switch installed it's now time to just operate and no more (I hope) fooling around with the antenna.

A great tool to have

Ready for inspection

The MFJ 1788 antenna has arrived I ended up ordering it from DX Engineering and cancelling the order at the local ham store. DX Engineering had the antenna in stock were as the local store was not able to tell me when the antenna would be in….it seemed to be a waiting game. Once ordering the antenna DX Engineering had it at my door in 3 days! I can't say enough about the great service that was provided by DX Engineering. Now having said that……..I have been doing a lot of online reading about 1788 loop and how over and

Capacitor

Control box test

over again they arrived damaged or just not working. Looking at the loop it seemed to be in great shape and externally survived the trip ok. As I looked at the control unit I found one of the  push buttons not working! The  range button that changes the meter from low to the high wattage scale . I opened the control box as I also heard some "rattling" noise from within the unit as well. I found the switch to be defective and in need of changing, the rattling noise was from the battery holder. It was only held in place with two-side tape and as you guess it….there was no holding left on the tape. At this point I had a choice to make:
1. Send the control box back to either MFJ or DX Engineering for repairs?
2. Ask MFJ if it's possible to make the repair myself if they were to send me the part?
I settled on option 2 as I could still use the control box until the switch arrived and not be put on hold until control box was repaired or replaced. (note: I purchased DX Engineering's last unit)

Stepper motor

The control box failed the QC check it was now time to open up the antenna (a must according to magnetic loop user group) The visual inspection looked very good now time to power up the antenna with the control box. With the cover still off the 1788 loop I wanted to make sure the internal capacitor moved freely and stopped when full rotation was reached in both directions.
All was going well until the capacitor was rotating counter clockwise and it just stopped! I then rotated the capacitor in the clockwise direction and back counter clockwise and it worked just fine. After many back and forth rotations the capacitor never acted up…..maybe this was a one off. I emailed MFJ regarding the switch and they are going to mail one to me so I can do the repair. Next is to mount the antenna and see how it performs stay tuned!

The loop horizontal and nothing.

In my last post I wrote about how my Alexloop was just not getting out in the condo, I was checking the Reverse Beacon Network as I called CQ at 5 watts from my condo and there was ZERO spots! Well from that post I received lots of great suggestions on how to get VE3WDM's signal from the antenna to the world. So here is what I tried........I mounted the Alexloop in the horizontal position in the condo and it netted no spots on the Reverse Beacon Network. I then put the Alexloop on the balcony seeing that we are 60 feet in the air I felt this was a sure thing. The last option for me was to place an antenna on the balcony as it was open season to the condo cops.  I placed (in the cover of darkness) the Alexloop on the balcony and called CQ on 20m and 40m and then check the Reverse Beacon Network. To my surprise there were no spots and now I am really stumped and frustrated. The Alexloop is out in the open 60 feet in the air and no spots what the heck is going on......do those dam condo cops have ham radio jammers!!!!!! Up to this point I have only use the RBN to check for spots but there is also WSPR and I have had some bloggers suggest I use this. At this point I am not able to get WSPR up and running as there seems to be some software issues. My goal now is to sort out the issues and give WSPR a go both with the Alexloop in the condo and out on the balcony. This coming weekend I hope to get on the air with WSPR and give that a go! Im really not frustrated I see this as a challenge, for me to get ham radio on the air from a condo will but only  help others in the same situation as me get on the air.