[Lowfer] Ground wetness vs. impedance for ground dipole

jrusgrove at comcast.net jrusgrove at comcast.net
Thu Jun 2 22:32:49 EDT 2016


Warren

Thanks for the info ... very interesting. Didn't get a chance to listen during the day. Just tuned 
in now and signal is good copy again tonight.

Jay W1VD  WD2XNS  WE2XGR/2


----- Original Message ----- 
From: "Warren" <k2ors at verizon.net>
To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <lowfer at mailman.qth.net>
Sent: Thursday, June 02, 2016 8:08 PM
Subject: [Lowfer] Ground wetness vs. impedance for ground dipole


> Jay,
> To answer your question I looked at some impedance data that I logged with my vector impedance 
> digital wattmeter, the LP-100a. Measurement was made through the old 4:1 step down balun and about 
> 100' RG-8x.
> Dry conditions resonance (X=0) at 471kHz, R=26.7 ohms
> Wet (after heavy rain) resonance 421kHz R=87 ohms
>
> So substantial changes in both R&X
>
> 73 Warren
> ----- Original Message ----- 
> From: <jrusgrove at comcast.net>
> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <lowfer at mailman.qth.net>
> Sent: Thursday, June 02, 2016 9:17 AM
> Subject: Re: [Lowfer] [600MRG] WH2XIL 137.7798 and 470 kHz
>
>
>> Warren
>>
>> Interesting. Wonder what the impedance change is ... some R some X or all R or all X.
>>
>> Jay
>>
>> ----- Original Message ----- 
>> From: <k2ors at verizon.net>
>> To: <lowfer at mailman.qth.net>
>> Sent: Thursday, June 02, 2016 8:16 AM
>> Subject: Re: [Lowfer] [600MRG] WH2XIL 137.7798 and 470 kHz
>>
>>
>>> Jay,
>>>    The reason I dropped the power down is that the OGD is sensitive to ground moisture, when the 
>>> ground is really dry the antenna impedance drops and the Class-D transmitter will deliver more 
>>> power, sometimes causing an over-current trip out. The difference from dry to wet conditions is 
>>> greater than 3:1  in terms of power output.
>>> The power drops as dew forms at night and the impedance rises. It drops by an almost 4:1 ratio 
>>> after a heavy rain.
>>>
>>>
>>> 73 Warren K2ORS
>>> WD2XGJ
>>> WD2XSH/23
>>> WE2XEB/2
>>> WE2XGR/1
>>>
>>>
>>> On 06/02/16, k2ors at verizon.net wrote:
>>>
>>>
>>>
>>>
>>> Hi Jay,
>>>
>>>
>>> I am leaving it on, however I dropped the power down quite a bit this morning to about 36 Watts 
>>> out since I am away until sometime this afternoon.
>>>
>>>
>>> 73 Warren K2ORS
>>> WD2XGJ
>>> WD2XSH/23
>>> WE2XEB/2
>>> WE2XGR/1
>>>
>>>
>>> On 06/02/16, jrusgrove at comcast.net wrote:
>>>
>>> Warren
>>>
>>> Tnx info.
>>>
>>> That's by far the loudest I've heard you're station transmitting on the OGD (on ground dipole). 
>>> Will
>>> it be on during the day today and again tonight?
>>>
>>> Jay
>>>
>>> ----- Original Message ----- 
>>> From: "Warren K2ORS" <k2ors at verizon.net>
>>> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <lowfer at mailman.qth.net>
>>> Sent: Thursday, June 02, 2016 5:32 AM
>>> Subject: Re: [Lowfer] [600MRG] WH2XIL 137.7798 and 470 kHz
>>>
>>>
>>>> Jay,
>>>> Ground dipole, aprox 80W. I did wind a new transformer for the dipole using FT-240-77 8 turns
>>>> primary, 12 turns secondary.
>>>> Thanks for the advice and nice audio clip!
>>>>
>>>> 73 Warren
>>>>
>>>>
>>>>
>>>> On 6/1/2016 10:14 PM, jrusgrove at comcast.net wrote:
>>>>> Warren
>>>>>
>>>>> Power, antenna on 470 kHz?
>>>>>
>>>>> Short .mp3 at http://www.w1vd.com/WH2XIL060116.mp3 .
>>>>>
>>>>> Jay W1VD WD2XNS WE2XGR/2
>>>>>
>>>>>
>>>>>
>>>>> ----- Original Message ----- From: "Warren" <k2ors at verizon.net>
>>>>> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands"
>>>>> <lowfer at mailman.qth.net>
>>>>> Cc: <600mrg at w7ekb.com>
>>>>> Sent: Wednesday, June 01, 2016 3:45 PM
>>>>> Subject: [600MRG] WH2XIL 137.7798 and 470 kHz
>>>>>
>>>>>
>>>>>> WH2XIL 137.7798 QRSS 60
>>>>>> and
>>>>>> 470 kHz CW
>>>>>>
>>>>>> Reports welcome!
>>>>>> 73 Warren
>>>>>>
>>>>
>>>>
>>>> ---
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>>>>
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