Topband: Inverted L improvement question - Part 2

[Todd Goins]

A person emailed me to ask if I could take SWR readings at the rig without
a tuner. Since my antenna analyzer is non-op due to the AM station nearby.
The feedline is about 140' of LMR-240.

Here is the indicated SWR at the 7300:
1.810 1.2:1
1.830 1.3:1
1.850 1.5:1
1.870 1.8:1
1.900 2.3:1
1.940 3.0:1

Todd - NR7RR

On Fri, Dec 28, 2018 at 7:30 PM Todd Goins <tgoins at gmail.com> wrote:

> Charlie,
>
> Yeah, I know the 100w is not ideal. This is night #2 with the elevated
> radials on the 100' vertical. I spent every day last week trying to use the
> 100' vertical against my buried radial field. It was horrible on transmit
> and mostly deaf (high noise) on receive. The attenuator didn't help, it
> just isn't hearing stations. My 43' vertical top loaded with 90' of
> horizontal wire is way, way more effective.
>
> I'm using a 230' BOG as my primary receive antenna right now but I can
> switch in the transmit antenna to listen just by throwing a switch.
>
> I'll stick with this 100' antenna for a while and try to use it this
> weekend on the Stew Perry but I have a feeling I'll be back with the 43'
> before it is over.
>
> Thanks,
> 73
> Todd - NR7RR
>
> On Fri, Dec 28, 2018 at 7:19 PM charlie carroll <k1xx at k1xx.com> wrote:
>
>> Todd:
>> So, I might shorten the antenna up a bit to get the lowest SWR point a
>> bit higher in the band.  But, as it sits right now, your SWR is not
>> indicating a problem.  You're talking only a 100 watts which gives you at
>> least 1 strike.  I would play with it as is for a few days and get some
>> idea as to how well you are hearing and how well you are transmitting.
>>
>> Without detailing you, 160 is a place where you need patience and/or a
>> low-noise receiving antenna.  Plus, you also need to know whether you are
>> being affected by local noise sources.  Another reason why I encourage you
>> to spend more time evaluating the antenna.
>>
>> 73 charlie, k1xx
>>
>> On 12/28/2018 10:07 PM, Todd Goins wrote:
>>
>> Hi Charlie,
>>
>> I can measure SWR at the rig. Feedline is about 140' of LMR240 coax.
>>
>> SWR at:
>> 1.810 1.2:1
>> 1.830 1.3:1
>> 1.850 1.5:1
>> 1.870 1.8:1
>> 1.900 2.3:1
>> 1.940 3.0:1
>>
>> I wasn't too worried about the choke situation but I connected in-line
>> what I had on hand, figured it wouldn't hurt. Mike had just asked what I
>> was using so I let him know. I'm not having any symptoms of RF in the shack
>> but I'm only running 100 watts.
>>
>> 73,
>> Todd - NR7RR
>>
>>
>> On Fri, Dec 28, 2018 at 6:56 PM charlie carroll <k1xx at k1xx.com> wrote:
>>
>>> Todd:
>>> So, what do you expect the air-wound choke to do for you?  Many, many,
>>> many antennas operate fine without a choke.  Don't get yourself wrapped
>>> around the axle that the antenna won't work without a "correct" choke.
>>>
>>> What's SWR are you measuring at the transmitter?  How long is the
>>> feedline?  Sure, it would be better to know what the Resistance and
>>> reactance are.  But, SWR will give you some idea as to where you are at.  I
>>> think right now, you don't really know what your ground truth is.  Tell me
>>> the SWR at 1.8, 1.85, 1.9, etc.
>>>
>>> 73 charlie, k1xx
>>>
>>>
>>>
>>> On 12/28/2018 9:30 PM, Todd Goins wrote:
>>>
>>> Hi Mike,
>>>
>>> Oh, I would totally believe that the air-wound choke is ineffective at
>>> 160m. It just happens to be what I had available to use when I rigged up
>>> the elevated radials in the cold rain yesterday. I figured I'd put it in
>>> line just in case.
>>>
>>> Thanks for the choke links, I will read the info on those sites.
>>>
>>> The air-wound choke is what I'm using when I'm feeding the antenna using
>>> the elevated radials. When I was testing using my buried radial field it is
>>> a different setup. There I have a DX Engineering radial plate that neatly
>>> ties everything (remote tuner, and DX Engineering Maxi-core Feedline
>>> Current Choke) together at the feed point.
>>>
>>> Thanks for the comments and info.
>>> 73,
>>> Todd - NR7RR
>>>
>>>
>>> On Fri, Dec 28, 2018 at 5:57 PM Mike Waters <mikewate at gmail.com> <mikewate at gmail.com> wrote:
>>>
>>>
>>> Hi Todd,
>>>
>>> I'll bet the farm (if I had one) that your air-core choke is ineffective.
>>> Take at look athttp://www.karinya.net/g3txq/chokes to see what I mean.
>>>
>>> A very, very good common mode choke is the one I have on mine, fromhttp://audiosystemsgroup.com/RFI-Ham.pdf. There is no better material
>>> written on this subject, either in print or on the Internet.
>>>
>>> 73, Mikewww.w0btu.com
>>>
>>> On Fri, Dec 28, 2018 at 7:34 PM Todd Goins <tgoins at gmail.com> <tgoins at gmail.com> wrote:
>>>
>>>
>>> ... I do have a common mode choke at (near) the feed point. It may or may
>>> not
>>> be effective at 160m. It does work on 10-80m. It is about 25' of RG-8 coax
>>> wrapped around a 4" PVC pipe as a form. Perhaps not ideal... No RF noted
>>> in
>>> the shack.
>>>
>>> 73,
>>> Todd - NR7RR
>>>
>>>
>>> _________________
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>>>
>>