[TowerTalk] Need balun advice

Tue Nov 10 19:10:05 EST 2015

Welll...Yah, usually, maybe.  I agree, regardless of the SWR reading, it 
is no indicator as to how well the antenna is working. Period!

Is this a new antenna with the 30 meter add on, or an A3WS that was up 
and has had the 30 meter element added?  It makes a big difference!

IF OTOH, and I emphasize the "IF" an antenna has been up and working and 
Then the SWR goes up. or DOWN then and only then it's a good indicator 
that "something" has gone wrong in the antenna system.  It does not tell 
how well the antenna is working.  An AIM is an improvement, over plain 
SWR and can tell the Op a lot more "about" the antenna.  System can be 
almost anything on either end of the feed line, or the feed line itself.

As individuals, we tend to use the "shotgun" approach to 
troubleshooting, jumping from what ever we think it might be to the next 
"might be", instead of using a structured approach.  Much depends on 
what has transpired between when the antenna was last known to work and 
when it was discovered that it didn't work.

If this is a new antenna, I agree with Jim and say, use the 
Manufacturer's recommended balun.  Don't complicate matters by changing 
things before knowing the antenna works.

In most cases checking the last thing changed is where we start with a 
careful visual inspection. Then check connections, but in this case it 
appears to me that both the 30 meter add on and the balun are new.

Often and I mean "really often", our approach to troubleshooting makes 
things worse.  I say that as having spent nearly 26 years in Industrial 
instrumentation (maintenance) where I've seen most any mistake made that 
can be made and I made a lot of them.   I've also been a ham since 
spring of 61 (over 54 years).

Technically(and I know Jim already knows this) the word Balun is a 
contraction for BALanced to UNbalanced.  All other uses are a misuse of 
the word, but like DeepFreeze (I'll bet a lot have to look that up), 
misuse of the word has caused it to lose its original meaning, so, as 
you said, when we read Balun, the writer may mean one of many things.  
IOW, Balun is now accepted as a generic term for almost any device 
between the feed line and the antenna.

One added note.  12 to 15 foot spacing is the distance I used to mount 
my 7L 6-meter C3i above the old TH-5.  It sounds really close for the 
A3WS and the tribander.

It "sounds" to me as if the problem is spacing.  As for the balun, if 
you have one, test it before doing all that extra work.

73

Roger (K8RI)

On 11/10/2015 4:51 PM, Jim Brown wrote:
> I don't think it's coax, I think it's simply interaction between 
> antennas and Les's misunderstanding of the importance of SWR as an 
> indicator of antenna performance.
>
> Repeat after me --
>
> SWR is NOT an indicator of antenna performance.
> SWR is NOT an indicator of antenna performance.
> SWR is NOT an indicator of antenna performance.
> SWR is NOT an indicator of antenna performance.
> SWR is NOT an indicator of antenna performance.
> SWR is NOT an indicator of antenna performance.
> SWR is NOT an indicator of antenna performance.
> SWR is NOT an indicator of antenna performance.
>
> OTOH -- the "balun" used should be exactly what the antenna designer 
> recommends. The word "balun" is used to describe (at least) a dozen 
> different things that are VERY different from each other. The 
> operation of the antenna, as well as the match between antenna and 
> feedline can be greatly affected by which is used.
>
> So -- study the instructions for the antenna, use exactly with the mfr 
> recommends, and if you want to minimize RX noise, ADD a common mode 
> choke on the coax side of the mfr's recommended matching device, as 
> described in by Cookbook. k9yc.com/RFI-Ham.pdf
>
> 73, Jim K9YC
>
> On Tue,11/10/2015 1:38 PM, Les Kalmus wrote:
>> Chris,
>>
>> I had a similar problem that turned out to be the coax. It leaves the 
>> top of the tower over an arm, then hangs. The center conductor 
>> migrated at the top of the arm.
>> I had to cut that section out and remounted everything but hung the 
>> coax from the arm with a cable grip from McMaster. No problems since.
>>
>> From your description, you should probably recheck the coax and make 
>> sure there are no points where there is pressure that could cause the 
>> center to migrate and change as the tower is raised.
>>
>> Les w2LK
>>
>> On 11/10/2015 12:54 PM, Chris Wynn via TowerTalk wrote:
>>> OK, see if this changes any opinions. When I put up the A3WS at the 
>>> towers nested height of about 30 feet, 12 meters swr was flat, 30 
>>> meters was flat, and 17 meters was around 1.8:1....
>>> Now, with the A3WS MOUNTED OVER THE th-7, 12 METERS is 1.8:1, 30 
>>> meters is 3.1:1, and 17 meters is 1.0:1........
>>> I have the A3WS mounted about 10 to 12 feet above the TH-7. While 
>>> talking to Mark at DX Eng., he brought up the issue of spacing 
>>> between the TH-7 and the A3WS..... Originally, I thought that the 10 
>>> to 12 feet of space between the two would be enough.  However, at 
>>> this point, I HAVE NO CLUE! Would it be worth moving the TH-7 above 
>>> the A3WS?????
>>> While coming home for lunch,  I worked the 5Z4 on 17 meters with the 
>>> tower nested.... Hell if I know at this point!!!
>>> AS TO THE QUESTIONS ON HOW I MEASURED THE SWR, I have used both the 
>>> MFJ 259 and the radio's (FT-1000 field) and get the same 
>>> measurements.... And have measured the swr at the end of the coax 
>>> connected to the balun on the yagi.....
>>> The TH-7 is working just fine......
>>> I appreciate all of the help and advice...My XYL is livid with me as 
>>> I have been totally consumed with these problems, and as much as I 
>>> like RF, I LIKE "THAT" better and don't want to end up divorced;)
>>>
>>> Chris
>>>   Christopher L. Wynn
>>> Attorney-at-Law
>>> Christopher L. Wynn, ESQ., P.C.
>>> 8473 Earl D. Lee, Suite 300
>>> Douglasville, Ga., 30134
>>> (770)942-8661 (Landline)
>>> (770)577-1626 (Telecopier)
>>> chris at chriswynnlaw.com
>>>
>>>
>>>       On Tuesday, November 10, 2015 10:40 AM, "K7LXC at aol.com" 
>>> <K7LXC at aol.com> wrote:
>>>
>>>    >  Last week I had the antenna back on the ground and 
>>> disassembled every trap on it, and found nothing out of the 
>>> ordinary. ?     So what was the swr when it was on the ground? Did 
>>> you check it?     You need to first ascertain that your antenna 
>>> looks like an antenna; i.e. it has a dip somewhere. Put your antenna 
>>> analyzer on the antenna and work your way back from there.      BTW 
>>> many times an "antenna problem" turned out to be something in the 
>>> shack; e.g. coax jumper, coax switch, etc. Cheers & GL,Steve      
>>> K7LXCTOWER TECH
>>>
>>>    _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk

-- 

73

Roger (K8RI)

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus