I have a Alinco DJ-X11 all mode hand held dual receiver that covers from about
50 hz to 1.2 Ghz. I have it programed for 3.7, 7.1, 126 Mhz, 335 Mhz, 1 Ghz
all in AM or SSB. It's quite a package and goes in my vest pocket used with a
ear bud for secret noise locating and bug detection. Not as cheap as some of
the others.
Dale, K9VUJ
On 23, Apr 2013, at 9:56, Pete Smith N4ZR <n4zr@contesting.com> wrote:
> I have an Icom shirt-pocket dual-bander that covers the 136 MHz aircraft
> band. bought at Dayton for <$100. I built a Moxon for that frequency from a
> QST article, useful because of its cardioid pattern. Since you don't need a
> calibrated attenuator, just about anything will work, so long as you get the
> signal strength down as you approach the source.
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network at
> http://reversebeacon.net,
> blog at reversebeacon.blogspot.com.
> For spots, please go to your favorite
> ARC V6 or VE7CC DX cluster node.
>
> On 4/22/2013 9:48 PM, Util.RFI.pro wrote:
>> Just about every full feature handheld offered to the Amateur market today
>> has a receiver that covers .5 to 470 MHz or 1 GHz. A 3 element yagi for 150
>> MHz is easy to build (or buy). An attenuator is very helpful. Coax connects
>> the yagi to the attenuator and the attenuator to the radio. This basic setup
>> should be able to pinpoint a source to a pole or a house.
>>
>> In my opinion, the MFJ RFI searching device is only marginally useful unless
>> you actually have some idea how to DF radio signals. RFI is a radio signal.
>> You DF RFI much the same way you DF any signal.
>>
>> You need a receiver that can listen on the affected frequency in AM mode and
>> has some means of showing signal strength. A directional antenna at the
>> frequency of interest is very useful. A means of keeping the maximum signal
>> strength indication at about midscale is required. That means the receiver
>> must have an attenuator or an external attenuator must be used.
>>
>> Practice on known signals to develop skill. Then set out to locate the RFI.
>>
>> Used radios can be had for under $200. Suitable yagi antennas cost less than
>> $30 in materials to build. Attenuators can be bought or made. Storebought
>> attenuators can be expensive. Homemade attenuators can be cheap and
>> effective. At hamfests I find all kinds of professional attenuators for $10
>> and up. Coax jumpers with BNC connectors are not usually expensive.
>>
>> Hope this helps. Good luck.
>>
>> 73, Frank KB4T
>>
>>
>> Sent from somewhere in Frank's electronic universe
>>
>> On Apr 21, 2013, at 10:54 PM, Gary Mayfield <gary_mayfield@hotmail.com>
>> wrote:
>>
>>> Frank,
>>> This is good to know.
>>> Is there anything you would recommend starting with? My father is
>>> deperate to find the noise in his little town. The utility has been out
>>> three times, and of course each time was immediately after a rain and the
>>> noise was not present. Most days it S9 or better accross the bands. The
>>> last time I was down there it seemed like it was coming from all directions.
>>> He has the MFJ handheld unit, but he hasn't had much luck with it.
>>> Thanks and 73,
>>> Joe
>>>
>>>> Date: Sun, 21 Apr 2013 21:18:46 -0400
>>>> From: utility.rfi.pro@gmail.com
>>>> To: paul@n1bug.com
>>>> CC: rfi@contesting.com
>>>> Subject: Re: [RFI] Ultra Sonics
>>>>
>>>> I have all of the Radar Engineers equipment. As a utility interference
>>>> investigator I'm fortunate to have good tools. The ultrasonic unit is only
>>>> useful AFTER I've already found the source pole. Even then the ultrasonic
>>>> detector is able to hear the actual source only 40% of the time.
>>>>
>>>> The ultrasonic detector is not able to hear arcing inside a transformer or
>>>> any other device where the arcing is inside a metal or plastic
>>>> case/container.
>>>>
>>>> Frankly I could do my job just fine without the ultrasonic detector. With
>>>> its low productivity and limited usefulness, my success rate would be
>>>> impacted only slightly.
>>>>
>>>> Spend money on tools that will do the most for you. By that I mean
>>>> directional indicating equipment that will pinpoint the pole, house or
>>>> structure. If the source is a pole, a crew will touch everything until the
>>>> source is found and corrected. If the source is in a house or other
>>>> structure you will use a small receiver possibly equipped with a
>>>> directional antenna to walk up to the source.
>>>>
>>>> Save the ultrasonic purchase for last.
>>>>
>>>> 73,
>>>>
>>>> Frank N Haas KB4T
>>>> Utility RFI Investigator
>>>> Florida
>>>> Disclaimer: I was on the beta test team for the RX3.
>>>>
>>>> The RX3 is a huge improvement over the RX2. I have not tested the RX1 but
>>>> looking at the schematic I suspect the RX3 would beat it by a wide margin.
>>>> In tests with a controlled spark source, the stock RX2 (predecessor to the
>>>> RX3) with 12 inch dish could detect the spark to a distance of 35 feet. The
>>>> RX3 with the same dish could detect it at 100+ feet.
>>>>
>>>> I would definitely go with the larger dish. Actually I would prefer 18 inch
>>>> were it available. I will add that I am very disappointed in the quality of
>>>> the dish, which I have communicated to the proprietor on several occasions.
>>>> The detector used requires a very flat dish. Upgrading/modifying using one
>>>> of the other dishes available on the market has not proven practical
>>>> because they are all too deep and/or just just as poor in conforming to
>>>> parabolic shape as the supplied dish. At some point when my budget allows,
>>>> I plan to try a deeper/better/larger dish with a different detector (one
>>>> having a wider acceptance angle or "beamwidth").
>>>>
>>>> Outside the scope of your question: I would NOT use ultrasonics to FIND
>>>> noisy poles. You want radio receivers for that. Use the ultrasonic to
>>>> verify and find specific hardware that is sparking once you have located
>>>> the pole.
>>>>
>>>> 73
>>>>
>>>> --
>>>> Paul Kelley, N1BUG
>>>> RFI Committee chair,
>>>> Piscataquis Amateur Radio Club
>>>> http://www.k1pq.org
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