Actually, it comes out 19.23, although not at all critical on a ground
plane.
73
Butch
WA0VJR
Node 3148
Wallace, ks.
On Sat, 17 Aug 2013, Tom Behler wrote:
> Mark:
>
> This does help.
>
> I will check in my junk box to see if I have an old magmount and 2-meter
> vertical antenna that I might have forgotten about.
>
> Although I don't think I do, it may be worth the effort to be sure.
>
> Thanks also for the clarification on the formula.
>
> Steve's formula suggests the counterpoise length should be approx 20 inches,
> so I'll probably start there and adjust if needed.
>
> Tom Behler: KB8TYJ
>
> ----- Original Message -----
> From: "Mark WZ0K" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Saturday, August 17, 2013 4:29 PM
> Subject: Re: 2-meter Antenna Challenge
>
>
>> Hi Tom,
>> First, the formula for a quarter wave is: 234 divided by the frequency
>> in MHz. For the 2 meter band you will want something about 19 to 19.25
>> inches.
>> The mag mount I was using had an NMO connecter on the mag mount and
>> one
>> simply screwed the antenna on to this. Thus, it was fairly easy to loosen
>> the connection a fraction of an inch and slide some bare stranded wire
>> against the outside conductor in the NMO connection. No hand tools
>> required.
>> Smile. If you have a completely sealed unit, this would take some surgery
>> on
>> the antenna.
>> I hope this helps.
>>
>> God bless,
>> Mark and Noella
>> God loves You!
>> My personal website: Http://www.christiantraditions.info
>> The Blind Computer People List:
>> http://christiantraditions.info/mailman/listinfo/blindcomputerpeople_christiantraditions.info
>> Follow me on Twitter: https://twitter.com/TorgersonMark?refsrc=email
>> -----Original Message-----
>> From: Tom Behler
>> Sent: Saturday, August 17, 2013 3:00 PM
>> To: [log in to unmask]
>> Subject: Re: 2-meter Antenna Challenge
>>
>> Mark:
>>
>> So, now I'm thinking of two things here.
>>
>> First, the magmount I have is sealed, so I'm not sure how I would get to
>> the
>> shield of the coax to make the connection you describe.
>>
>> Also, I'm doing some mental calculations as to the length of the
>> counterpoise.
>>
>> Can someone refresh me as to the formula you would use for that, keeping
>> in
>> mind that I'd like the antenna to perform best around 146
>> megahertz--pretty
>> much in the center of the band.
>>
>> Tom Behler: KB8TYJ
>>
>> ----- Original Message -----
>> From: "Mark WZ0K" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Saturday, August 17, 2013 2:45 PM
>> Subject: Re: 2-meter Antenna Challenge
>>
>>
>>> Hi Tom,
>>> On The antenna situation. Some years ago, I had a 5/8 wave mag mount
>>> that I used in a window sill. It performed well enough. However, After
>>> hearing about using a counterpoise, I loosened the antenna from the mag
>>> mount and slid a thin piece of wire between the antenna and the mag
>>> mount.
>>> I
>>> made sure it touched the metal part of the bracket that was connected to
>>> the
>>> braid of the coax. The wire was cut to a quarter wave. Suddenly my
>>> reports
>>> were better in all the repeaters, and I started reaching in to machines
>>> that
>>> I could not reach before. I hope this helps.
>>>
>>> God bless,
>>> Mark
>>> God loves You!
>>> My personal website: Http://www.christiantraditions.info
>>> The Blind Computer People List:
>>> http://christiantraditions.info/mailman/listinfo/blindcomputerpeople_christiantraditions.info
>>> Follow me on Twitter: https://twitter.com/TorgersonMark?refsrc=email
>>> -----Original Message-----
>>> From: [log in to unmask]
>>> Sent: Saturday, August 17, 2013 11:32 AM
>>> To: [log in to unmask]
>>> Subject: Re: 2-meter Antenna Challenge
>>>
>>> Two suggestions:
>>>
>>>
>>>
>>>
>>>> Hi, all.
>>>>
>>>> I hope I am not wearing out my welcome back to the list, but I have a
>>>> challenging antenna situation I'm currently facing in the new faculty
>>>> office
>>>> I will be occupying starting this Spring semester.
>>>>
>>>> I currently have an old Kenwood TMV7A in the office, with which I have
>>>> always had at least some luck, in terms of getting into our local
>>>> 2-meter
>>>> repeater. The repeater is about 15 miles from the University.
>>>>
>>>> However, in my new office, I am finding that the small mag-mount antenna
>>>> I
>>>> have always used simply does not allow me to reach the repeater
>>>> consistently. Currently, I have the magmount sitting on a small metal
>>>> bracket on the window sill in the office. It is right next to the
>>>> window,
>>>> so I would think that should help. However, I do not have much of a
>>>> ground
>>>> plain for the magmount. I also think there is some de-sensing going on
>>>> with
>>>> the steel of the office building, and with other surrounding computer
>>>> equipment in the office complex.
>>>>
>>>> I do have a filing cabinet on the other side of the office that I could
>>>> use
>>>> as a ground plane, but the top of the filing cabinet is too high, and
>>>> there
>>>> is not enough space between it and the office ceiling to accommodate
>>>> the
>>>> magmount antenna.
>>>>
>>>> This obviously is a very challenging situation, and I also have to be at
>>>> least somewhat concerned with appearance, in terms of not having an
>>>> ugly-looking antenna that might draw more attention to what I am trying
>>>> to
>>>> do than I might want.
>>>>
>>>> Do any of you have any suggestions as to how to help the mag-mount
>>>> perform
>>>> better in this situation?
>>>>
>>>> Or, might I be better off considering another type of antenna, such as a
>>>> J-pole of some sort.
>>>>
>>>> I would appreciate any thoughts.
>>>>
>>>> Tom Behler: KB8TYJ
>>>>
>>>>
>>>
>>
>
>
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