If you were close to a quarter wave, that would be bad, but I don't 
think you are.  say   for a half wave, 492/2 for a quarter wave, so 
246/1.9 times .66 for velocity factor is comes out to 85.45 feet.  The 
only reason a quarter wave per say would be bad is that a quarter wave 
looks like a short if it is open and an open quarter wave looks like an 
open if shorted.  That is how tuning stubs work.  If you have around a 
hundred feet, forget it.  Back in the days when I sold and serviced cb 
radios and people ran 102 inch whips, they had all kinds of problems 
with static electricity taking out the f e t front ends.  I's put in a t 
connector at the radio with a shorted quarter wave stub which gave a dc 
ground, but as far as 27 meg was concerned, an open stub.
73
Butch
WA0VJR
Node 3148
Wallace, ks.


On Sat, 12 Nov 
2011, Mike Cozzolino wrote:

> hello tom, 100 feet of coax is not even a quarter wave of feed line
> on 160m.  if you take in to account the velocity factor of your coax,
> you are very close to an electrical quarter wave on 160m.  so do not
> cut your feed line.  and as far as coiling up the excess, think of
> the rf chokes that are made by coiling up coax.  make the coils about
> a foot in diameter, and you will be ok.  you need to shorten the
> antenna and don't cut off the extra wire, just wrap it back on the
> antenna so you can have plenty of adjustment.  you may not ever get a
> 1 to 1 swr, but you should get an swr close enough to make the radio
> happy.  ok on the counter poise, that sounds ok.  i don't know how
> high the antenna is off the ground both at the fed end and the lower
> end, but remember you are way under a quarter wave.  un less you have
> a tower that is 130 feet tall smile.  your antenna is seeing lots of
> capacity from the ground.  so for that reason you will find the
> antenna is going to be some what shorter to resonate at the desired
> freq.  take care, c u 73 mike
>
>
>
> At 04:50 AM 11/12/2011, you wrote:
>>     Mike:
>>
>> The shield of the coax is connected to a counterpoise, and the sloper is
>> grounded to my galvanized steel mast via a ground wire and a ground rod.
>>
>> Based on what you say, then, I will not worry about the extra coax, at least
>> for now.
>>
>> This is all a major learning experience for me, and I appreciate everyone's
>> patience.
>>
>> I am replying to a number of posts privately here, but I will post replies
>> to the list if I think they might help others, and also because I want folks
>> to know that I am listening.
>>
>> Thanks again, Mike, and all.
>>
>> 73 from Tom Behler:  KB8TYJ
>>
>> ----- Original Message -----
>> From: "Mike Cozzolino" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Friday, November 11, 2011 10:53 PM
>> Subject: Re: Need helping making sense out of contradictory SWR readings
>>
>>
>>> hi again tom, yes the broadcast station is messing up the
>>> analyzer.  i can not use my mfj 269 here because of the a.m.
>>> broadcast and have talked to others that have found the same to be
>>> true.  so forget the analyzer, and go by the swr bridge.  leave the
>>> coax to your 160m antenna alone, 100 feet is nothing to even to
>>> consider.  adjust the length of the 160m antenna and by the way what
>>> do you have the shield of the coax connected to?  the shield at the
>>> feed point.  you need to work against a tall tower or a counter
>>> poise.  but like i was saying earlier tom the only to get a accurate
>>> swr reading is right at the feed point or through an electrical half
>>> wave or multiples of that.  since you really can't do the latter then
>>> adjust for the best swr that makes the radio happy.  the tw1 is a
>>> very poor device, it is not very accurate, and remember swr bridges
>>> have diodes and again the voltage that is coming down the feed line
>>> from the local broadcast will also effect the swr bridge.  so put
>>> your radio at about 10 watts to override the broadcast effects.  good
>>> luck, c u 73 mike
>>>
>>>
>>>
>>> At 07:00 PM 11/11/2011, you wrote:
>>>>     Mike:
>>>>
>>>> You have a very interesting point here about local broadcast signals.
>>>>
>>>> I happen to live about a half mile from the tower for the only commercial
>>>> A
>>>> M radio station in our little Michigan town. ... It broadcasts on 1460 AM,
>>>> with a night-time power of, I believe, 1000 watts.
>>>>
>>>> Are you saying that this is what's messing the analyzer  up?
>>>>
>>>> Again, just to be sure I'm understanding you, are you saying ignore the
>>>> analyzer, and just go with what my TW1 and TS590 meters are saying?
>>>>
>>>> Obviously, my 160 meter antenna is still too long electrically, so that
>>>> will
>>>> need to be shortened.
>>>>
>>>> But, here's another question:  When we put up the 160 meter sloper, I only
>>>> had a 100-foot piece of RG8X coax to connect between the antenna and the
>>>> rig, which gives me about 40 feet of excess coax. ... Should I cut that
>>>> coax
>>>> to only what I need?  Would that change anything?
>>>>
>>>> Again, you are giving me some very interesting observations here.
>>>>
>>>> 73 from Tom Behler:  KB8TYJ, Big Rapids, MI
>>>>
>>>>
>>>> ----- Original Message -----
>>>> From: "Mike Cozzolino" <[log in to unmask]>
>>>> To: <[log in to unmask]>
>>>> Sent: Friday, November 11, 2011 9:30 PM
>>>> Subject: Re: Need helping making sense out of contradictory SWR readings
>>>>
>>>>
>>>>> hello tom, the analyzer is almost useless on 160 and 80m
>>>>> antennas.  the reason is because you have so much broadcast signals
>>>>> coming down the feed line that the analyzer is all messed up.  in
>>>>> areas where folks don't have the broadcast crap the analyzer does the
>>>>> fine job.  so go by the swr bridge and ignore the analyzer.  even a
>>>>> swr bridge is influenced by the length of the feed line, you could
>>>>> have a 1:1 some where along the coax where the swr is really much
>>>>> higher.  the only way to use an swr bridge is through a electrical
>>>>> half wave to the antenna or with the swr bridge at the feed
>>>>> point.  you can also use multiple electridal half waves between the
>>>>> swr bridge and the ant.  take care, c u 73 mike
>>>>>
>>>>>
>>>>>
>>>>> At 05:28 PM 11/11/2011, you wrote:
>>>>>> Hi, folks.
>>>>>>
>>>>>> Well, I have managed to get hold of an MFJ 259B antenna analyzer to
>>>>>> help
>>>>>> try
>>>>>> to figure out what is going on with my 80 meter and 160 meter sloper
>>>>>> antennas that we put up a few weeks ago.
>>>>>>
>>>>>> However, when taking some preliminary readings with the analyzer
>>>>>> tonight,
>>>>>> and comparing them against what my TW1 watt meter and the SWR meter on
>>>>>> the
>>>>>> TS590 say, I am getting very confusing results.
>>>>>>
>>>>>> Let me give a few examples:
>>>>>>
>>>>>> On 80 meters, my sloper has an SWR of about 5 to 1 on the top and
>>>>>> bottom
>>>>>> of
>>>>>> 80 meters, with a dip of 1.0 to 1 around 3.887 mhz.  But, when we put
>>>>>> the
>>>>>> analyzer on the antenna, it shows the lowest SWR to be about 1.3 to 1
>>>>>> at
>>>>>> 3.887 MHZ, but the SWR's skyrockets quickly on either side of that null
>>>>>> to
>>>>>> infinity on the lowest part of the band, and to over 8.1 to 1 on the
>>>>>> top
>>>>>> of
>>>>>> the band.
>>>>>>
>>>>>> With my 160 meter sloper, my lowest SWR is about 5 to 1 at the very
>>>>>> bottom
>>>>>> of the band, according both to my TW1 and the TS590 SWR meter, but the
>>>>>> needle on the analyzer doesn't even budge when tuning through the
>>>>>> entire
>>>>>> band, and stays up at some ungodly figure of an SWR of about 20 to 1.
>>>>>>
>>>>>> I just checked for a short  on my coax feed lines, and there does not
>>>>>> appear
>>>>>> to be any problem there.
>>>>>>
>>>>>> We are using fresh batteries in the analyzer which were just bought
>>>>>> tonight.
>>>>>>
>>>>>> Are we perhaps not adjusting the analyzer correctly?
>>>>>>
>>>>>> I am sure that, to some, all of this seems very elementary, so please
>>>>>> bare
>>>>>> with me while I do some learning here.
>>>>>>
>>>>>> 73 from Tom Behler:  KB8TYJ
>>>>>
>>>
>
>