[bars] Measuring wire antennas

[William Smith]

Ah, so the cap is in series with the antenna wire at the 1/3 point (from the driven end).

Makes more sense, thanks!

73, Willie N1JBJ

> On Sep 26, 2022, at 12:04 PM, Tim KC1RET <kc1ret.radio at gmail.com> wrote:
> 
> I used this load cap in the wire element: https://batteryeliminatorstore.com/products/40m-end-fed-insulator-kit <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 <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 <mailto: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> <mailto: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 <mailto: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


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