Excellent advice re: attenuator.
Once while using MFJ 856 (135 mHz RX & 3 element), it got completely
overloaded within few hundred feet of source.
While being in close and overloaded, the field strength meter went down to
zero.
73, Alan K0AV
On Wed, Jan 17, 2018 at 8:43 AM, Dave Cole (NK7Z) <dave@nk7z.net> wrote:
> Actually Don, we are both agreeing with Jim, K9YC with regards to the dish.
>
> I could not agree with you more with regards to an attenuator. My biggest
> problem was overload. I am in the process of building an attenuator for my
> MFJ three element 135 MHz beam, and radio. MFJ put the receiver at the
> feed-point, so adding an attenuator involves moving the radio to the
> handle, via an attenuator.
>
> I have been using loops of late, they have a really sharp null, and if you
> hang a hunk of ferrite material at the feed-point, on the coax, the pattern
> gets even sharper!
>
> I also move up in frequency, and prefer that as opposed to adding
> attenuation. If I can reduce signal that way, I do, else in comes the
> attenuator.
>
> Most locates of late have been just drive around with the truck, listening
> on 40 meters, and shorten/lengthen the screwdriver as needed to attenuate
> signal.
>
> The last locate took 5 minutes that way, and I am in month 2 of taking
> notes to make sure if the FCC is involved, I have done it all correctly.
> Hopefully the light owner will just add filters, and that will end the
> issue. I always worry about contacting light operators... One of these
> days I will find a crazy one...
>
> 73s and thanks,
> Dave
> NK7Z
> http://www.nk7z.net
>
> On 01/17/2018 05:41 AM, Don Kirk wrote:
>
>> I agree with Dave, an audio dish would be the last thing I would buy
>> (lowest priority item). A problem I found while working with the local
>> power company that had an ultrasonic dish is that we could detect arcing on
>> every pole we checked, but out of all the poles we checked there was only
>> one pole that was the root cause of the RFI I was hearing at my house 1.1
>> miles away.
>>
>> The most important feature I have found on any of my portable radio
>> direction finding systems (HF or VHF) that I use for tracking down RFI is
>> the ability to throw in a lot of attenuation when I get close to the
>> source. If you get close to the source and the signal is full strength
>> even on the nulls of the antenna, there is then no way you can do
>> additional direction finding.
>>
>> Don (wd8dsb)
>>
>> On Wed, Jan 17, 2018 at 8:23 AM, Dave Cole (NK7Z) <dave@nk7z.net <mailto:
>> dave@nk7z.net>> wrote:
>>
>> Hello Mike,
>>
>> No need for the dish, it just locates arcing, and that is the Power
>> companies job. Across the two years I had a dish, I think I used it
>> once or twice.
>>
>> Better you save your bucks and build a loop with the saved cash. You
>> will get a lot more use out of the loop than the dish.
>>
>> 73s and thanks,
>> Dave
>> NK7Z
>> http://www.nk7z.net
>>
>> On 01/16/2018 08:36 PM, W0MU Mike Fatchett wrote:
>>
>> Thanks all!
>>
>> Other than the ultra sonic dish I have most of the other pieces
>> parts.
>>
>> Appreciate all the links and hints too!
>>
>> W0MU
>>
>>
>> On 1/16/2018 9:17 PM, Dave Cole (NK7Z) wrote:
>>
>> Hi,
>> See:
>>
>> http://nk7z.net/rfi-now-house-cleaning/
>> <http://nk7z.net/rfi-now-house-cleaning/>
>>
>> for a three part series on how I managed to calm down my RFI
>> environment. Also see:
>>
>> http://nk7z.net/sdr-rfi-survey-p1/
>> <http://nk7z.net/sdr-rfi-survey-p1/>
>>
>> for a tool to characterize your RFI.
>>
>> 73s and thanks,
>> Dave
>> NK7Z
>> http://www.nk7z.net
>>
>> On 01/16/2018 11:39 AM, W0MU Mike Fatchett wrote:
>>
>> What are people using for noise sniffing? I saw the MFJ
>> dish but I try to avoid their stuff.
>>
>> I know there is no one perfect tool.
>>
>> W0MU
>>
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