ASPiSYS Part 15 Antenna

That looks substantially similar to the center loaded antenna featured in an article I wrote about my antenna trials.

It does resemble MRAM's pictures that I recall seeing on the site somewhere.

But it does look like it is true to what it claims to be and is rather expensive, but then again if you were manufacturing and selling these the price would seem just right.

Everything shown is easy to replicate with hardware parts, and copper would be better than aluminum.

The coil is the most tedious part to make by hand, but many members have wound their own coils.

The top hat is often claimed by some RF engineers to do little or nothing to improve the range of a 3-meter antenna, while others claim good results. Main thing I believe is that a top hat isn't going to hurt anything.

The linked webpage states, "There are no need for extra ground leads that will add to the total length (maximum measured dimension) and no transmission lines should be inserted between it and the transmitter you will use for feeding it. !' 

And,

 It should be noted that:

* The length of the eight horizontal (top hat) conductors at the top of this ~2.8-meter-long, assembled vertical structure might be added to that vertical length by an FCC field inspector -- which would make the antenna non-compliant with FCC §15.219(b).  Also...

*  A "safety ground" conducting path connecting the r-f ground terminal or chassis of a Part 15 AM transmitter (FCC-certified or not) to one or more conductors buried in the earth will radiate over the entire length/height of that conducting path.  While this conducting path is or has been strongly suggested even by the manufacturers and agents of some FCC-certified Part 15 AM transmitters (and others), it also may make such an installation non-compliant with FCC §15.219(b).

Maybe something to consider?

That's almost the (discounted) price of a Procaster or Rangemaster.  I wonder just how much extra range you really will get using this compared to those 2 transmitters with their tuned whips, and whether that would make it worth the extra cost?  In my experimentation, I've gotten similar ranges to their claims (over 1 mile) with a ground mounted Rangemaster.

Rich does make a valid point about the top hat.  The safety ground issue has been discussed many, many times here, and the prevailing thought is that it's always better to mount your transmitter and/or antenna at ground level, if it's possible, to avoid potential issues with the FCC.

Given that a certified transmitter (the Talking House with its wire antenna, no modifications) was recently cited by an FCC inspector (see the recent FCC thread), I would think that it would be best to go with a plain, vanilla, unmodified and certified transmitter, at least in the near future.

If memory serves, it was Dog Radio Studio 2 who shared something told him in a conversation with an fcc inspector, which I paraphrase as best I can:

"We'll approve anything in a 10x10-foot cube."

That remark, at face value, seems to dismiss top hats as not being part of the significant length.

But, as Rich suggests, if I'm understanding, is that an inspector MIGHT measure the top hat spokes as part of overall length.

It's that kind of uncertainty that leaves part 15ers in a state of not quite knowing what they can do.

It seems rude when rules are used like russian roulette.

$450???? he can keep it!!!!!! maybe $50.00 plus ship but $450!!!! he's crazy. thats beyond lunacy.

Seems to me that "a plain, vanilla, unmodified and certified transmitter" is exactly what Gerald Gaule was using.

So, where's the beef?  

Unless that TH/I AM exceeded 100 mW input power, which apparently was not verified by the field agent, it was a "a plain, vanilla, unmodified and certified transmitter" installed per Part 15.219.

That's what I mean.

The NOUO ignored 15.219.

The beef was ignored.

Something is up with this kind of enforcement in which some rights and rules are being bypassed.

I suspect a holocaust against part 15 radio.

Too bad that Jerry Gaulle didn't want to fight it.  I can understand why - cut your losses, don't waste time and focus on the Internet.  However, it sets a bad precedent, particularly for those who focus on the radio broadcasting - and not everyone does Internet streaming.  I hope Radio Systems can intercede and at least get some clarification as to what went on in that particular case.

I've been wondering if the inspector felt that a part 15 am transmitter must comply with both 15.209 and 15.219, or a reason was given as to why 15.219 did not apply.  

This is a MONOPOLE antenna. A monopole absolutely requires an RF connection to ground to function at all. It drives me nuts whenever someone advertises that a ground is not required for their variation of a monopole antenna.

To be accurate, this ad states "no need for extra ground leads". Interpretation of "extra" is fuzzy, but a non-tech reader will easily interpret this as "Hey, this is great. No ground needed". WRONG!

No time to do a lookup right now, but there have been a number of discussions in the past about top hats. A top hat with ground radials is a very standard way of improving range in regular commercial or government installations. The NDB here at Friday Harbor Airport uses a 40' antenna with both top hat (6 rods) and ground radials (12 @ 50' each), gets out rock solid (the ADF receiver in the plane) for navigation purposes to about 35 miles on 25 watts.

Note: this is old technology, many here feel it was a waste of $$ to build a new one (to replace one torn down for building hangars). The new one is exactly like the old one, had to be built, wired, tested, and flopped over before the old one could be turned off and torn down....because the FCC and FAA will not authorize building or licensing 'new' NDB stations.

The local Ham Radio club has tentative access to the new one if no one bids a price on it, which they have a year to do. Nothing so far, so I think I can assume the club will get it to use for mountong new digital repeaters.

I am a member. If they set it up, I'll negotiate for mounting space on it to get a microwave digital signal, hoping to send audio to other Part 15 AM installations in the middle of the island.

I meant "access to the <em>old</em> one" (of course).

Also, Carl - you have a very good 

memory.  Several years ago, an 

FCC inspector did tell one of my

closest friends about the "10 foot

cube provision."  But I don't know if

that 10 foot cube holds any water now.

Bruce, The Dog Radio Group