The AM Forum

Today my friend and I, installed the array solutions coils.  These coils are 2 inch cores about 93 turns.

The coils attach to my open wire line and then to an 8ft ground rod.

The plastic box is water tight and is from Home depot. It cost about $20. I used Stainless screws as studs with water proof GE silicone around bolts where they pass through.  The Ground side connector is a standard Ground rod mount with the half taken off.  THis made for a perfect mount for the Ground side of the coils on the inside.

The total project cost about $35 in parts.  The coils where pricey at $83.  I would wind my own and will from now on. These are nice but not that nice.

The good news is that tuning of the antenna has not changed at ALL.  The RX has alot of noise removed. We are in a light storm right now and the overall noise level is the lowest its been. Signals are clear. The main reason for this was to stop the arcing I was getting at the back of the tuner.

Clark

Be careful with silicone some types rot copper. The best stuff I have used is the gray stuff used in mil applications. I learned the hard way.

Nice Job OM!

Looks neat and well done.

THe silicone is not touching any copper. Its only on the enamel and on the cover seal to the box. I also put it on the threads of the stainless screws as they passed through the box. Not on the electrical connections.

Is there any chance it can go through the enamel coating? I doubt it. Its dried.. Its been hours since applied and the coils are working as normal.

Clark

Clark,

The silicone shouldn't have any impact on the coils.  A lot of the varieties of caulk out-gas corrosive fumes during the curing phase (that lovely vinegar smell) and this has created problems in the past.  I recall from my novice days one of our club members installed 2 way gear for police and other commercial users and they ran into a problem with these fumes causing connector corrosion.  One of the major producers (probably GE) sold a version specifically designed for use around electronics since it did not cause this problem.  I think QST also had a note on this in the mid 70's.

Those are very nice looking coils (basically operating as RF chokes I imagine).  Putting a choke across verticals was pretty standard practice also to drain off the charge build up and providing a DC ground really does quiet things down.  But I have never seen any chokes before that qualified as "eye candy", you really need a plexiglas cover to show them off  :)

I had a piece of this wire left over so I smeared the silicone over it on a paper plate. If it corrodes, I will know. I think I am ok. We looked this up on the web. I did find that from now on, use Bathroom or plumbing grade product. They will never bother the copper since its used near copper pipes.

Thanks for the comments. I am on the air now and things seem better.  Before, The pops would whipe out the RX. Now its just noisey out.. Not big pops.


Clark

Seal or not to seal?

I had a 68 VW that developed a nice rust hole dead center in the drivers door. I would expect to see rust at the door bottom. I finally got to tear the door panel off and found that the sound deadening tar soaked panel had a bubble in it. It never got any air but did hold moisture. Comparable to a empty sealed pop bottle sitting in the sun. Rain forrest.

This could create the same situation inside your sealed box and corrode your connections.

Very interesting. I wonder how critical the inductance value is. What gauge wire is that? 16?

Good looking coils. Same here wondering if the value of inductance was calculated? What bands are you operating with the open wire fed antenna?

Very nice installation Clark!  The only thing that you might consider doing is adding some ceramic feed thru insulators for the line going thru the wall.  You might experience some breakdown there if you run much power.  We really don't experience that kind of static build up on antennas around here.  Must have something to do with the amount of humidity (or lack there of) and the amount of dust in the air, etc.  Anyway, looks like you have found a nice solution to your problems.

73,  Jack, W9GT

Get rid of those crimp on wire terminals! ! ! ! ! or cut the plastic off and slobber them! Acid rain will cause oxidation problems in the not so distant future.

Always use soldered on lugs for RF connections, or they will come back to bite you!

                                                                    The Slab Bacon

 

Drill a hole on the down facing surface. Epoxy a small piece of fine mesh screen over the hole on the inside surface surrounding the hole to keep the bugs out. This allows the inside and outside 'atmospheres' to remain in harmony and reduce moisture buildup inside the box. Breather plugs are made for this purpose but aren't cheap.   

word up.

I'd have to agree.  I had a 'discussion' with Jay via email and direct on another reflector (Jay, at Array Solutions).

We went back and forth about a weep hole in the bottom of their remote antenna switch.  I said no, he said yes.

Bottom line is, the weep hole went into the install, and now there is no problem.

Weep hole goes on the BOTTOM, where no water can get IN, you only want it so condensation has a place to escape.

Lots of Mil Spec cases have the one way breather hole vents, if you can find them.  I have a nice dive case set up with one, but I dunno how far it's capable of going underwater.

And echoing what everyone else said about solder, too.  Non soldered connections = diode.  You SURELY don't want a couple diodes across your feeders to ground, dew ya?

(pun intentional :) )

--Shane

I love this board! 

All connectors are soldered.  Those are not crimp terminals.. I love you guys!!  I cant believe that you actualy thought I used Crimp on connectors..and no solder.  I cant get no respect. hahaha

There is a weep hole in the box. At the bottom.  Thats not an issue here in AZ though! I love you guys again!

I had a small scrap of this wire I cut off the coils. I put GE Silcone from the same tube on that scrap of wire and placed it on a paper plate.  I woke up this morning. The Sealant is cured and there is NO sign of rot or corosion on the copper section or on the Enamel coated section.  Just to be safer, I sent an email to GE that was on the tube. This morning they wrote that silicone 2 does not corrode metals.  But other products they do sell could.

I dont think I need the insulators through the wall. Its fiberboard, spray in type insulation and a wooden wall. Those holes are also sealed. I just took the picture before sealing the holes.  Its been running like that for 6 months with out issue.

These coils on this installation is RF safe until around 140 mhz or so.   This antenna is used for 80,40,20 and 15.  Tuning at the tuner did not change on any band. 

The amount of static that is removed from my system is just incredible.  I spent 4 hours on the radio last night because this is the first time in months I could hear everyone without all that damn noise. Not a single reciever POP last night or today..  This has to be the best thing I have done to this station.  I highly recomend this to anyone using a simliar antenna in a climate like arizona.

Cya!

Clark

Well, you did buy your coils from Array Solutions.......    ;)

Key word being "BUY"....

I digress.

Shoulda done that 2 years ago, when I was there with that boat, and told ya about 'em!  One single one works GREAT on coaxial cable!

--Shane

Yeah Shane.. I am building a box to install a coil outside for the vertical.  It will have two Ns on it for the hardline to pass through.  This will solve the arc and noise on that antenna.

I guess if we buy anything we looked down on :)

I gotta go... Its lunch time and I have to go Ground the wheat by hand for my bread.


Clark

We only looked down upon for ADMITTING publicly to purchasing.

Especially you, what with a half dozen or more restored by you boatanchors :) lol.....

Friggin Appliance Operator....  FAO, as in Schwartz.

--Shane

Hardly. Complaining about those who have helped you solve your problem will get you looked down on.  

Watch your fingers in the wheat grinder. Oops, sorry, I was just trying to be helpful.   :D

Clark,
Nice job..........I think u made the correct choice going with the coils (chokes).

Bill

Thanks bill.   I used the antenna on 40 today. I cant believe the difference.. S4 noise level!  My friend was showing 20DB on the reciever (local am'r).  I unhooked the ground and ran back in.. Same 20db over.  When he unkeyed. the noise is S7!   That is a huge decrease in noise with no loss in actual signal. 

I cant wait to get on the AMI net tonight with the Globe king 500C.  Its been months since I could talk to the west coast guys with all that noise. I am praying for a good band tonight! 

THanks to everyone that helped me with the advice and install of this system!

Clark

I have a few spools of #18 and #14 . I'll sell the coils for $41.50 and I'll throw in a few extra turns.

Frank,
Reminds me of when some years ago I mentioned to a buddy at work that I wanted a couple of well-built picnic tables, treated lumber, etc. and not the shoddy, "first rot guaranteed" ones sold at Lowes for $25. 
    Bloviated that I'd even pay $100 for a table that was built properly.  You know, announced in the same kind of voice that screechs, "give me a good, stacked sandwich for $5 anytime over a $2 thin, little meat gyp.

 Well, he said, "OK, you got 'em for $100 each," in the presence of a third guy so I was kind of stuck. 
    So he shasays down the the very same Lowes, buys $50 worth of treated lumber and some carraige bolts and said, "come and get 'em," about two weeks later. 
    Everybody had a good laugh, but, come to think of it, it's been 20 years now and I still have one; left the other one in the northwoods of Pa. at old house.

***********

Boy, I really like the idea of a static sink.
It sounds like just the ticket for my modified windom before the "L" net tuner.

I think I'll build one up; use up the old 4:1 balun ferrite core (or should I stick with air coil?) and some old #12 wire from Warefdale xover coil.

I always used the carbon resistors, and they worked well.  I was always scared of wirewounds or a coil, because of series resonance.  With the thread before, and some 'prodding' from some members here, I VNA'ed ww resistors, and they seemingly work well, too.....

BUT, a static sink, as you put it, is nice.  That, and a GOOD receiver with a low noise floor, and you can hear things that wheren't even there before!

--Shane

  Clark,

   Just think with your new lowered noise floor on 75m, you might actually copy some of those 30 DB / S9 guys practicing the "East Coast Audio"!  ;D

Good Post,
Jim
WD5JKO

I will sure try!   IN the winter I could hear you guys and sometimes talk over there..  Thanks for the comments!


Clark

Incorrect. All of the Silicone rubber sold for home use uses Acetic Acid (the "smell") for the cure, with moisture. It is the residual Acetic Acid that causes corrosion. GE sold "Sil-Pruf" which is a non acetic acid silicone rubber material. ONLY those products that do not use the acetic acid cure method will not have any corrosion issues.

IF the corrosion could be an issue over time is another matter. It won't happen all that fast in most cases.

                 _-_-bear

Edit: I just read the comment on Silicone II - I do not believe it. I used the stuff recently, and it uses acetic acid cure system... I think one would need to contact the industrial side and get an application engineer for an accurate response. The consumer side usually has no clue in my experience. But it would be nice if it was true.

Bear. Thanks for your concerns. However, I spoke with GE directly and they explained that this product I used is NOT corrosive.  Some products are but most are not these days.  Its not a worry to me as I did not put silicone on any area that is touching copper. It is touching stainless at the screw threads but it wont harm the stainless even if GE lied to me.

Clark

Well, to overkill the whole condensation thing to the highest degree, why not purge the box with nitrogen. If theres no air, there will be no humidity, and in the event that the dew point is reached inside the box, there will be no condensation forming on anything.

I have some control systems in building basements around here where humidity would kill them. Some of these controls run in the $20K range, so protecting them is a priority when they cant be installed in conditioned space. The boxes they are in are setup in such a way that they can be purged completely, then set with 2psi of nitro along with a pressure switch wired into the control alarm circuit. Pressure loss lights an idiot light on the control panel and causes the system to store a code and blink a light in the managers office so he can call u$. (oops, did I hit the dollar sign instead of the 's' again, lol.)

Anyway, in the case of one of these outdoor boxes like yer coils are in, as long as your box is air tight, you could drill a 1/4" hole in the cover, shove a blowgun in there with a small tube on the end, and let nitrogen flow for a couple minutes at around 2-3psig. The air will be chased out thru the hole around the outside of the tube leaving only a nitro atmosphere inside the box. Have a 1/4" pipe plug handy already white taped and pull the tube out slowly with the nitro still flowing. Get the tube out and send the plug in right after it sealing in the nitro charge.

Years from now, someone will buy that from your estate auction off epay, open it up, and be amazed at how well preserved the interior components are.

On edit: I have a TMC kw balun around here somewhere that used the same technique with the nitro and the insides look like the day they made. It's 60 years old or so and started life at a some coastal station.

73
 

In some color TV sets that used 9 or 12 pin based sweep tubes, the sweep tube and damper were often held in place by a "large" drop of gray silicon on the base where it touched the tube and socket and the wires from the socket. There was never any corrosion even when the sets were 15 years old.

Yeah.. There is no issues these days with modern products. I have researched it. Even GE told me this wont happen anymore. The products are used and misused in plumbing all the time.  I am not worried because I did not use it on any metal. I just used it on the plastic lid and to hold the coils down. 

I am really enjoying my new RX!  Not one single reciever POP since the install. I have been through storms and high winds.. Nothing.  My only regret is that I did not do this a long time ago.

CLark

So are these type coils a good idea for anywhere? Not just the desert southwest?  Will it kill my QRN in thunderstorm alley here in middle Tennessee?   Did anybody advise what inductance would be ideal?  I'm thinkin of just winding up some to try. 93 turns on 2" diameter form. What is the center form made of?

They are a good idea if you don't use a DC Grounded antenna.  If your antenna is already at DC ground, no bennie.

Form can be anything.

I used the formula (and I can't remember where this came from) of 10 times Xl at lowest freq. of interest.  Ensure you sweep coil to ensure no resonances as well.

--Shane

http://www.66pacific.com/calculators/coil_calc.aspx

It will do nothing for thunderstorm QRN.

Yes and no..  If you hear lighting crashes on the reciever.. we cant stop that. However, If you hear crashes and POPs that take out the RX for a moment, The coils might help.  Before, I would hear the crash over the air and the RX would pop up in the Red. The AGC would pull back and then take a moment to give RX back.  This is totaly solved with the coils in my situation. Since the install, I have not had one time where the RX has been knocked out and the pops are GONE.   I have talked on the air with storms passing by 50 miles out. Major noise and crashes.. Not one pop on the RX.

I installed one on my vertical and again.. This really lowered noise.  You can use a project box or a large Coffee can for the enclosure.  Just install two panel mount coax connectors on the can. Then mount the coil inside. One side of the coil to the hot lead and one to the metal on the can. Then, Ground the can to a good ground rod.

I have been really enjoying radio again.  But maybe this solved other issues and other sources of noise that dont come to mind for system. Its Dry here. We have lots of Ground source lightning and lots of summer monsoons. Its a wirlwind of electrical activity where I live.

Clark

Clark,

I'm happy your having good luck with those Array Solutions inductors. Mine work fine as well. Yes they are a bit expensive but after trying them I'm sure you see how easy they are to copy.

Something you might want to add now are some spark gap's for lightening protection. The way I found those Array Solutions inductors was by trying an Ice Products combination spark gap and static drain box. The drains failed instantly under AM duty cycle so I gutted them and replaced both with the inductors instead of the ferrite core devices Ice Products used.

I'm looking now at the spark gap devices in the box. They look like small neon bulbs with ridiculously small conductors that would turn to vapor in an instant if I got hit.

I'm going to try this idea (picture below). It will take two heavy duty spark plugs (one on each side of the feed line) and I think I'll put the gaps in a sealed box to keep bugs and dirt out.

Mike

Neat idea.. I saw that used in an issue of QST once.  I could mount the plugs in my box.

Clark

What you were experience was not thunderstorm QRN. It was static build up on your antenna. Two largely different things.