Posts Tagged ‘Antenna trouble shooting’

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I heard a loud bang!

May 2nd, 2017 | Author:

Oliver likes the other use for the antenna cover
The inside looked great
Over this past weekend I was not able to get out and about with KX3 and CHA P Loop for portable ops as the weather was not very co-operative. I decided to throw the switch on the K3 at home instead, I really did not find too much on the bands. My antenna as I have mentioned in the past is the MFJ 1788 Mag loop. For me to get on the radio the antenna has to be moved to the centre of the balcony and a feedline brought out to it. This is only a 2 minute job to accomplish and the plan most of the time is when I am done to remove the coax and store the antenna back in the corner of the balcony. Now and then I leave it where it is after setup as I may want to use it later. On Saturday I left the antenna in the “operation position” overnight. I woke up at about 3:30 AM to some very loud and strong winds, I thought I should go and get the antenna and put it to the side in its stored position. Then as that thought was leaving me I heard BANG!!! The wind had blown the Loop over and it hit with a very loud bang. I went out right away and up righted the antenna removed the coax and placed the antenna off the side.  Later in the morning I brought the antenna in to inspect it for damage. The outside looked good but it was the antenna tuning capacitor and circuitry end of the antenna that made the loud contact with the concrete floor. I removed the covers and was pleased to find no damage had been done. I then tested the antenna and all was good. Lesson learned, it only takes to minutes to put it to the side and bring it out again. This is worth the time as opposed to spending HUGE money on a new antenna or getting it repaired.  With taking the covers off it allowed me to also do my annual inspection of the antenna as well. 

An SWR anomaly….that suddenly popped up!!

December 1st, 2016 | Author:
SWR on 15m...and hoping to see it again on 20m
During the CQ WW CW contest last weekend the SWR on my K3 was jumping around from 1.4, 1.6, 1.3 and back to 1.6 and so on. This “flutter” has never happened in the past also it was only happening on 20m. All the other bands were just fine, I left this anomaly alone during the contest as most of my contesting was done on 15m. The next day once the contest was over it was time to look into it. I first wanted to check to make sure the issue still existed, as in the past I have had things just “disappear” to never happen again. The issue was still there so it was time to investigate.
My setup is as follows:
-        Elecraft K3 operating at 5 watts.
-        MFJ 1788 mag loop antenna.
-        The coax is 30 feet of RG8X.
-        There is an LDG switch allowing me to switch between the K3 and KX3.
Here is what I did and what I found:
1 - I switched the K3 to antenna B which is my dummy load. I found the SWR was stable as a flat match.
2 - I also have the Elecraft KX3 so I hooked that radio to the same antenna system. The SWR did not flutter as it did with the K3.
3 - I then hooked the antenna up to the antenna “B” connection on the K3 seeing the dummy load worked on antenna B. There was still a flutter in the SWR.
4-  I then took the K3 out of service and opened it up tightening each and every screw I could find. This did not make a difference I still had the SWR flutter.
5-   Even though the SWR was stable when using the KX3 I went ahead and made sure all the PL-259 connectors were tight. They all were good and snug.

I then posted on the Elecraft reflector site what was happening and the results I listed above. To my surprise all the advice that came back echoed the same……RF on the coax and making it back to the rig.  I was informed that just because the KX3 did not have the issue did not rule out the feedline and or antenna. I did rule this out and was not going to look any further into anything other than the K3.
The following was some of the suggestions from the reflector.

1.     If you can move the antenna further away from your shack. I am not able to do this as I am in a condo and the antenna is on the balcony.

2.     Turn the antenna 90 degrees and see if the flutter becomes less.

3.     Add a counterpoise to the ground lug on the K3.

Upon reviewing all this great feedback and wondering where to start, it was very odd that up until this weekend I had NEVER had an issue with the SWR on 20m. Then it occurred to me something I always do when it come to my trouble shooting which is to ask myself “Is there anything I have recently changed or added?” I went over in my head and there was nothing at all I added or took away from the radio setup. I proceeded to go out on the balcony to rotate the antenna 90 degrees as my other advice to myself when trouble shooting is preform the easiest things first and see what happens. The rotation of the antenna did nothing and back out onto the balcony I went to rotate that antenna back. While out there I checked out our balcony Christmas light to see if any had burnt out……….wait a minute the lights were just put up 2 days ago…….this equals a change!!! But could balcony lights funk up 20m??? I unplugged the lights and removed the extension cord I used to plug them in. I checked out the K3 and 20m was just fine now. I then placed the extension cord back out leaving it unplugged and the SWR I found fluttered just a tiny amount. I then plugged the lights in and check, I found the full-fledged SWR flutter returned.  Therefor during the holiday season you will know I’m on the radio when the balcony Christmas lights are off!!


An SWR anomaly….that suddenly popped up!!

December 1st, 2016 | Author:
SWR on 15m...and hoping to see it again on 20m
During the CQ WW CW contest last weekend the SWR on my K3 was jumping around from 1.4, 1.6, 1.3 and back to 1.6 and so on. This “flutter” has never happened in the past also it was only happening on 20m. All the other bands were just fine, I left this anomaly alone during the contest as most of my contesting was done on 15m. The next day once the contest was over it was time to look into it. I first wanted to check to make sure the issue still existed, as in the past I have had things just “disappear” to never happen again. The issue was still there so it was time to investigate.
My setup is as follows:
-        Elecraft K3 operating at 5 watts.
-        MFJ 1788 mag loop antenna.
-        The coax is 30 feet of RG8X.
-        There is an LDG switch allowing me to switch between the K3 and KX3.
Here is what I did and what I found:
1 - I switched the K3 to antenna B which is my dummy load. I found the SWR was stable as a flat match.
2 - I also have the Elecraft KX3 so I hooked that radio to the same antenna system. The SWR did not flutter as it did with the K3.
3 - I then hooked the antenna up to the antenna “B” connection on the K3 seeing the dummy load worked on antenna B. There was still a flutter in the SWR.
4-  I then took the K3 out of service and opened it up tightening each and every screw I could find. This did not make a difference I still had the SWR flutter.
5-   Even though the SWR was stable when using the KX3 I went ahead and made sure all the PL-259 connectors were tight. They all were good and snug.

I then posted on the Elecraft reflector site what was happening and the results I listed above. To my surprise all the advice that came back echoed the same……RF on the coax and making it back to the rig.  I was informed that just because the KX3 did not have the issue did not rule out the feedline and or antenna. I did rule this out and was not going to look any further into anything other than the K3.
The following was some of the suggestions from the reflector.

1.     If you can move the antenna further away from your shack. I am not able to do this as I am in a condo and the antenna is on the balcony.

2.     Turn the antenna 90 degrees and see if the flutter becomes less.

3.     Add a counterpoise to the ground lug on the K3.

Upon reviewing all this great feedback and wondering where to start, it was very odd that up until this weekend I had NEVER had an issue with the SWR on 20m. Then it occurred to me something I always do when it come to my trouble shooting which is to ask myself “Is there anything I have recently changed or added?” I went over in my head and there was nothing at all I added or took away from the radio setup. I proceeded to go out on the balcony to rotate the antenna 90 degrees as my other advice to myself when trouble shooting is preform the easiest things first and see what happens. The rotation of the antenna did nothing and back out onto the balcony I went to rotate that antenna back. While out there I checked out our balcony Christmas light to see if any had burnt out……….wait a minute the lights were just put up 2 days ago…….this equals a change!!! But could balcony lights funk up 20m??? I unplugged the lights and removed the extension cord I used to plug them in. I checked out the K3 and 20m was just fine now. I then placed the extension cord back out leaving it unplugged and the SWR I found fluttered just a tiny amount. I then plugged the lights in and check, I found the full-fledged SWR flutter returned.  Therefor during the holiday season you will know I’m on the radio when the balcony Christmas lights are off!!


MFJ 1788 vs Weather

February 28th, 2016 | Author:
As like everywhere else it seems the weather up this way is as up and down as the solar conditions! Up this way we have been breaking records with both high and sometimes low temps. Along with this crazy weather comes conditions that can be very hard on our antenna systems. I have read on many blogs of fellow hams dealing with antenna damage due to wind, ice and heavy snow issues. My antenna foot print is a very small one and so I thought sheltered from many of the issues others have been dealing with. Here is my weather related antenna issue to add to the list of weather mishaps. On Wednesday this week Julie and I came home from work and she announced (as she was looking outside) “your not going to like this”. Not very comforting words as I had a look for myself and saw that the high winds had their way with my antenna! I have an MFJ 1788 mag loop antenna. It’s mounted on a tripod on our balcony of the condo. The wind had toppled it on it’s side and then tossed all around the balcony as well. I understand to most of the other hams out there with weather damaged antennas, mine is a walk in the park. In my humble opinion this is the only antenna I have, it’s not cheap to replace and I am very limited on my antenna choices. As a side note I usually place the antenna off to the side when not in use and that way it is totally sheltered from the elements. I admit I was lazy and figured it had been ok for a week with the antenna in that position………..WRONG! I stood the antenna back upright and there seemed to be no broken parts all was in tacked. I crossed my fingers turned on the K3 and gave the antenna a go, the lowest the SWR would go was 4.0:1 and higher on other bands……not good. Below are the steps I went through to eventually fixing the antenna:
In the above picture the 3rd fin from the left was perfect centre and all others had to match.

                  1.    Since the coax had a good few tugs on it as the antenna bounced around the balcony I       wanted to first make sure it was not the coax that was the issue. I put it on a dummy load and      (unfortunately) it tested fine.

2                    2.     I then inspected the PL-259 connector just to make sure it was fine and not on it’s way out due to unforeseen damage. It was ok as well.

3                    3.    I then brought in the MFJ 1788 antenna into the house and first had a look over of the outside case, SO-259 and the antenna loop. All seemed good this way.

4                    4.     It was now time to open up the plastic housing and have a look inside, I have had the antenna apart on occasion for routine maintenance so I had an idea of how things should look. There was no obvious signs of damage to any of the major parts.

5                    5.   It was now time to connect the coax and run the internal variable capacitor to the end of each stop via the control box.

Here is where I noticed two problems: 

·                        A.The spacing between the stationary fins and rotating fins was not equal at certain points along the variable capacitor.
·                                        B.  When the capacitor was fully seated in one direction both the stationary fins and rotating fins should sit flush with each other and some on the rotating section were sitting higher.

To fix the spacing problem (which I had to do then the antenna was shipped to me) I used a screw driver to manipulate the fins to even up all the air gap between fins. To repair the fins that were not sitting flush I was able to loosen a nut on the shaft that held all the moving capacitor fins in place. I then was able to adjust the fins that were sitting to high and make them all flush.
It's hard to see but from the left about 7 fins over the next five fins start to look odd, this is because these fins are not sitting flush with the other fins and they had to be adjusted so they were flush.
1                   6.    It was not time to cross my fingers and try the antenna (with plastic cover off) and see if this was in fact the problem. I was able to turn the antenna to 1.1:1- 1.1:4 on all bands and this was with the antenna sitting on a table in my living room. It seems the problem was fixed!
2                 
              7.  I then put the plastic cover back on and again check the SWR on all bands, I wanted to make sure nothing changed……. nothing did change and all was still good.

3                   8.    I then re-mounted the antenna on the tripod and covered it with my canvas patio table cover….so it does not “look” like an antenna. I then tested the SWR again…it was now 8:1!!

4                   9.    I then removed the canvas cover and the SWR was fine again…..seems canvas was damp do to the rain that accompanied the wind that day. I put the cover in the dryer and then back on the antenna and all was well. I am now going to purchase some waterproofing spray for the canvas to keep the antenna dry. 
     Below is one section of the fins that have been adjusted and are back to normal position.








Time to look inside the MFJ 1788

October 28th, 2015 | Author:
Taking a close look at things
It's the fall and time for some antenna maintenance for me there is no tower to climb or any outdoor work for that matter. It's as simple as bringing the MFJ 1788 indoors from my balcony and having a look. I have had the cover of the antenna off in the past so it was no problem to quickly remove it and start investigating. Some of the things I look for are poor solder joints, little critters who have made my antenna home, the smooth operation of the tuning capacitor and the over all health of the components.  It was a good thing I did check the mechanical connections and without exaggerating I have to say that almost all nuts were
Checking the cap fins
loose......some very alarmingly loose! The hardware holding the stepper motor in place was the worst but not far behind was the larger nuts that held the large tuning capacitor in place. I can't remember the antenna acting funky at all but I do believe it was just a matter of time before something reared it's ugly head like a quirky SWR! Another thing I like to do while the antenna is apart and fully cycle the tuning capacitor for not only smooth operation but the equal spacing of the moving fins along side the stationary fins. There was only some minor adjustments needed to the capacitor fins.........BUT where does "Murphy"  fit into this adventure........well just as I was finishing my adjustments the antenna slipped off the TV tables I had it on and the control wire that runs the motor broke off the circuit board! Also the "feed loop" wire was distorted somewhat. The feed loop is 10
Some of the many nuts that were very loose.
Control wire torn off.
gauge wire in the antenna that is contorted into a egg shape, this little baby can really play games with how the SWR outcome on the loop is determined. I played with it when I first got the loop and that was a mistake as it occupied about 2 hours of my time to get the antenna's SWR back to "normal". I vowed to never touch that feed loop again, but thanks to Murphy it seems I have to revisit that dark cave again. I re-soldered the stepper motor wires back in place and did my best with the feed loop wire. The antenna was put back together and with my fingers cross I tested it and to my utter surprise the unit was working better than it has in the past.

Weather VS MFJ 1788 loop

November 6th, 2014 | Author:
Outcome of my damp MFJ 1788
The weather has been up and down up this way from snow and minus 2C then up to plus 14C it's the top end of the temp scale that I enjoy but that will soon come to an end as winter is on it's way! While on the subject of the warmer weather also comes showers and damp weather, for some reason this has an affect on my MFJ 1788 isoloop. In past I have found my antenna to be SWR sensitive to the damp and or humid weather. I had posted on some of the mag loop user groups to see if  others had the same issue. I was not able to get lots of responses but the consensus was that weather really had no effect on others loop! I ended up taking my loop apart and just checking out the insides and all looked good.
The work of the internal tuner
Once the damp and or humid weather changed all was well with the loop. The effect on the antenna is the SWR will not go below 2.7:1 on any given band but any other time the SWR would be either flat or close to it. I posted about this very problem this past summer on my blog and it really was not a humid summer so the problem did not arise that often. Now that it has happened again my own conclusion is the damp weather has an effect on the dielectric characteristics of the air that separates the capacitor plates in the antenna. This by no means is a scientific conclusion but as for simple old me it's the conclusion I am leaning toward. I do have an internal antenna tuner in the Elecraft K3 and my Elecraft KX3,
The SWR of the antenna
this allows me to lower the SWR so the rig does not see the high SWR.

KX3 troubles

August 16th, 2014 | Author:

A happy looking KX3
I decided to take the KX3 out and about on my day off Friday, it was an overcast day so I thought it wise to do my operating from the mobile rather than taking the bike. I set up the mobile whip antenna on my car and situated myself in the passenger seat and was ready to go.(note….this time before the trip out I made a list of things to bring so I was not without important items as happened in the past)  Brought the KX3 up to the 20m QRP watering hole (14.060) and just wanted to check the SWR on the radio before sending out my 5 watts of raw power. The KX3 gave me an error message but it seemed I was still able to transmit and I did for a short time. Then I noticed as I moved up and down the band my
Not so happy KX3
SWR stayed the same at 1.4:1 no matter where I was on the band….even up into the SSB portion. It was then determined something was wrong and I had a fast look at the antenna and coax but all seemed ok. I then switched to my 15m whip antenna and the error message was gone but I still had this strange low SWR across the 15m band as well. So it was time to pack things up and head home. Once at home I put the KX3 on a dummy load and tried it out and all was just the way it should be. I then put the rig on the MFJ 1788 loop and again no problems. So I suspect it's the mobile setup and I did post the problem on the Elecraft reflector and was given advice to check the mobile setup. When at home I did want to give the KX3 the full workout and to do so I started to call CQ on 20m. Terry WA0ITP came back to me from Iowa and our signals were in around 339 and conditions wee not that great but we were able to carry on a decent QSO. So the KX3 is working good but it's just another "project" I have on the burner that has to be worked out.  No time today as I am on call  this week and the phone has not stopped ringing with calls for me to go in!
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