[bars] Measuring wire antennas

[Tim KC1RET]

I used this load cap in the wire element: 
https://batteryeliminatorstore.com/products/40m-end-fed-insulator-kit

The dimensions for the 80m EFHW, including the coax counterpoise, are 
also shown on that page.

The cap I am missing is within the 36:1 xformer; across the primary 
(coax feed) winding.

Clearer?

73,

Tim - KC1RET

On 9/26/2022 12:00, William Smith wrote:
> Now I'm confused (which is not unusual):
>
> You've spoken of a matching transformer/balun, and a choke, and a cap 
> at the midpoint of an end-fed antenna, but my brain just isn't working 
> right.
>
> Which parts from (I assume) 
> https://batteryeliminatorstore.com/collections/ocf-masters did you 
> assemble?
>
> 73, Willie N1JBJ
>
>> On Sep 26, 2022, at 11:52 AM, Tim KC1RET <kc1ret.radio at gmail.com> wrote:
>>
>> I have the cap in the midpoint of the 'driven' wire.  My 
>> understanding (albeit quite tenuous) is that the cap across the 
>> primary improves the performance on the higher bands.
>>
>> Frankly, if the cap doesn't help I may pull this down and opt for the 
>> 40m version as a test.
>>
>> 73,
>>
>> Tim - KC1RET
>>
>> On 9/26/2022 11:10, William Smith wrote:
>>> I’m surprised it works at all without the cap, let us know how it 
>>> does with the cap!
>>>
>>> 73, Willie N1JBJ
>>>
>>>> On Sep 26, 2022, at 10:45 AM, Tim KC1RET <kc1ret.radio at gmail.com> 
>>>> wrote:
>>>>
>>>>  MANY thanks to all who replied privately to my original plea!
>>>>
>>>> I go the thing (80m EFHW) up this weekend following the design on 
>>>> the OCFMasters website.  Well...  partial success.  Granted, I'm 
>>>> still waiting for the cap that goes across the primary at the 39:1 
>>>> matching xformer/balun and that it is still very low, only about 
>>>> 8ft above the ground at the lowest point.
>>>>
>>>> The SWR at a useful point in the band (measured at the choke) is OK 
>>>> on 80, 40 and 10, but really quite bad everywhere else.
>>>>
>>>> The missing cap is due from Digikey today. Stay tuned...  (pun 
>>>> intended)
>>>>
>>>> 73,  Tim - KC1RET
>>>>
>>>> On 9/22/2022 23:59, Jim Idelson wrote:
>>>>> The 'effective electrical length' of the wire is influenced by 
>>>>> several parameters. One of them is the physical length. Others 
>>>>> include the type of wire, the insulation and the height above 
>>>>> ground. Hard to know what that little loop from the main wire to 
>>>>> the balun will do. You don't actually know that electrical length 
>>>>> for sure until you measure it with a signal applied from your 
>>>>> antenna analyzer or transmitter.
>>>>>
>>>>> So, here's the Pro Tip: *Always make the initial cut on the long 
>>>>> side - a good foot to eighteen inches.* It's a whole lot easier to 
>>>>> trim bits off than it is to add length of you cut it too short.
>>>>>
>>>>> 73 Jim K1IR
>>>>>
>>>>> On Thu, Sep 22, 2022, 8:59 AM Tim KC1RET <kc1ret.radio at gmail.com> 
>>>>> wrote:
>>>>>
>>>>>     OK, time for newbie question...
>>>>>
>>>>>     When measuring the length of a wire antenna element, such as
>>>>>     an EFHW, do you include or ignore the bit from the end
>>>>>     insulator to the terminal of the balun?
>>>>>
>>>>>     Yes, I know, it will only amount to 4-6 inches but I'd rather
>>>>>     get it right from the start than have to add/trim later.
>>>>>
>>>>>     Thanks!
>>>>>
>>>>>     Tim - KC1RET
>>>>>
>
>

-- 

Courageously sent from a non-Apple device that /includes/ a headphone jack.

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      Tim Carter - KC1RET

			

	+1.978.710.0133 <tel:1.978.710.0133>

	kc1ret.radio at gmail.com

	https://kc1ret.com

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