[TowerTalk] DIY conduit locator?

[Grant Saviers]

Thanks for all of the suggestions.  They catalyzed a design I built.

I bought a DIP14 1MHz crystal osc on Amazon, so I built an RF source for 
3x AA battery power.  It includes a 5th order Butterworth LP filter 
(ELSIE cad) to be nice to others.

Hooked it to a spare 110' LDF4 in a 3" PVC conduit down 18" (2 other 
LDF4 grounded both ends are in the same conduit).  Using a Tecson PL660 
receiver I could find the conduit within a couple of inches over its 
full length by holding the receiver vertically at shoulder height.  A 
deep null was directly over the conduit. With the SSB BFO on, a same 
frequency local 50kw BCB audio was reduced to garbled.

Less than $20 for everything except Tecson (owned for RFI chasing).

Grant KZ1W

On 10/28/2020 12:19, Joe Subich, W4TV wrote:
> On 2020-10-28 11:11 AM, Grant Saviers wrote:
>  > Trying to find a design for a empty conduit tracer.
> 
> Plastic or metal conduit?  Empty or in use?
> 
> I've used my old "tone and trace" device to find buried wires
> (irrigation controls and valves) where I had some general idea
> where they were.  Something along the order of this:
> <https://www.google.com/aclk?sa=l&ai=DChcSEwiPhN62_tfsAhXFnLMKHUqjCDMYABANGgJxbg&sig=AOD64_0Pp00PBuNdaGEXNM7c-CFrDS0vOQ&ctype=5&q=&ved=2ahUKEwj1qta2_tfsAhWmpFkKHSq1BxEQ9aACegQIDhB6&adurl=> 
> 
> 
> Google "Wire tracer"
> 
> The alternative, if you have plastic/empty conduit is to push
> a single wire through it, ground it at the far end and feed
> the wire with an Elecraft XG3 at 0 dBm on 160 meters (tune it
> down to your AM radio range if you can).  I suggest 160 tuned
> down to AM so you can use the "null" of the AM loopstick to
> better locate the signal.
> 
> 73,
> 
>     ... Joe, W4TV
> 
> 
> On 2020-10-28 11:11 AM, Grant Saviers wrote:
>> Trying to find a design for a empty conduit tracer.  We've dug at a 
>> couple of places at the 501c3 where it was "supposed to go", NG.  
>> Seems to me this is a simple widget for energizing a test wire in the 
>> conduit or some sort of mouse - LF or magnetic placed on the end of a 
>> snake.
>>
>> Some googling hasn't found a design so hoping a towertalkian has a 
>> design or link to one that works.  This 2" conduit was installed some 
>> time ago at 24" depth but where it routes is now lost.
>>
>> The commercial tracers are $3000.  My budget is more like $20.  The 
>> usual AM radio and dongle SDR's are available.
>>
>> Also interested for when I need it to exactly locate my coax conduits 
>> before digging.
>>
>> Grant KZ1W