If you had significant radiation from the ladder line, you had an installation or design issue in the system. Perhaps a poor balun, or a grossly unbalanced antenna.

Some antenna tuners and some baluns actually force ladder line into UNbalance. A friend of mine had severe RFI, and it turned out to be the balun design he was using. The balun was actually designed in a way that forced gross unbalance!!

That aside, antenna tuners generally do NOT transform common mode. There is a false idea that common mode disappears, or is easier to handle, on the input side of a tuner. You can read about that here:

http://www.w8ji.com/tuner_baluns.htm

It's just math, but some people obviously have a real problem understanding how statistical math works. They think a dozen things or a few dozen problems out of 10,000 or 20,000 in service implies no QC at all.

There isn't much anyone can do with people who use illogical, irrational, numbers or arguments to indict or insult other people's credibility.

If I do nothing but supply facts, yet still someone will say something weird like this:


Of course they can be determined, not precisely, but close enough to know what is going on. AES even supplied information of the number of units that went to a local source, but the actual sales volume of AES Orlando is so low to be statistically meaningless in overall volume. That store represents just a few percent of sales.  

What is really bizarre about this is the person with the smallest most inaccurate sample, or people like you with no data at all, are the most authoritative and vocal about having usable data!!! Even to the point of calling other people uncredible.

One fellow down there flip-flops over and over on his data. Even the store disagreed with him.

That's pretty weird, if we think about it. It's almost like a personal campaign where people go out of their way, and even flip flop and cook meaningless data, just to damage someone.

73 Tom
  

  

That spacer carries current to the loading capacitor. Make sure that spacer is tight at the board end. To tighten it, remove the screw at the top and tighten the spacer by turning it snugly with pliers. The screw is fairly strong metal.  If the board has been damaged by arcing or heat, do what K8AXW suggests.

73 Tom

I don't know what you mean by:


Do you mean the statements by the fellow in Florida?

The general rules for two elements are:

A voltage fed element requires equal voltages with proper voltage phase lag or lead.

A current feed element requires equal currents in each element feedpoint, with proper current phase diffeence.



Phasing antennas at heights other than those that have current maxima or voltage maxima at the feedpoint can be very complicated, because neither voltage, current, or phase are what you might think. Because of that, I think you are biting off more than you should to try end-fire phased 5/8th wave antennas. I would stay away from it, and get my feet wet with 1/4 wave verticals first.

With 1/4 wave spacing, the optimal phase difference is around 110-120 degrees for skywave. This will place a null cone over the rear, and increase gain and improve apparent F/B ratio over 90 degree phasing.

Phase can change over a reasonable amount, perhaps from 95 to 125 degrees, without noticed changes. Improper current maximums, where they are not equal in current, will kill F/B ratio much more than small phase errors.

Read this carefully:

http://www.eznec.com/Amateur/Articles/Current_Dist.pdf

and this

http://www.eznec.com/Amateur/Articles/Simpfeed.pdf

but keep in mind OPTIMUM F/B on skywave does NOT occur with 180-S degee phasing. In other words, optmum phase with 90 degree spacing is NOT 90 degrees, nor is it 120 degrees with 60 degree spacing, or any other 180-S combination.
Unless you actually want less gain (wider pattern) or less rear rejection of signals, you really want the null offset slightly to the sides at zero elevation, so the null forms a cone around the rear.

I think the world is big enough that people can speak respectfully to each other and cooperate or accommodate each other reasonably. Usually any problem is a little bit of both sides.

Or has the TEA party invaded Ham radio mentality?

You probably do not want or need to change the number of turns, even if you change wire gauge.

If you borrow a gauge from someone in the HVAC business, all you need do is measure the pressure in the anode exit area and compare it to pressure in the air inlet plenum.

That is how tubes are actually rated, or by measuring temperature of various areas of the tube.

My amplifiers' inlet air system ducts in from below the floor in the summer, and out to the attic.
The air is reversed in the winter, and sucks down from the attic and exhausts under the floor in the winter. I do not use room air.

The final tester for the AL12 series line (AL82,1200,1500) and AL8x line (Al800,AL80B) is a different person than the tester for the AL811 and AL811H line. They are two different lines with different testers.

I'm looking at statistics for differences between those lines, excluding issues that would not be a testing issue (like shipping damage, infant relay receive issues, or bad tubes).

I really do not have any comment beyond that, except the failure rates seem very reasonable on the 80B line.

As I recall, this thread stems from a conversation where he was cautioned to keep leads short and to make a capacitor "boxy" instead of having a long path through the capacitor.

Any unnecessary series inductance in the capacitor, by using poor form factor, increases losses. This is not only because of the longer path, but also because the capacitor starts to behave increasingly like a transmission line. This is especially important in small loops because subtle changes insignificant in many typical resonant circuits (where load or source resistances are pretty high) cause large problems in a small loop (where the load, radiation resistance, is very low).

Also, any extra lead length that is not in the perimeter of the loop can cause deleterious changes in the radiation resistance of the loop.

The actual problems go far beyond a small ideal RLC circuit, because workings of a small loop system do not come close to either an ideal (or even a real) RLC circuit. One similar example is a typical antenna tuner. It handles nicely treating things as a simple network with real lumped components with modest load impedances. Stick a 10-ohm load on it, and things people don't even think about (like lead lengths and sizes) start to be major problems.

73 Tom

If you increase Q by increasing reactance with the same real part of impedance, you either increase voltage or you increase current, or you increase both. Neither is  desirable.

Your idea that resistance remains constant is flawed in the real world. Loss resistance has to increase, unless the additional reactance has infinite Q. If you add something that increases series inductance, you also add loss resistance. The resistance increases not just from the extra inductance, but system resistance also will generally increase just from the fact the capacitance decreases. Fields inside the capacitor are more concentrated.   

Q is, after all, the ratio of stored energy to working energy. This means increases unloaded Q with fixed loaded Q increases losses. After all, the ratio of unloaded Q to loaded Q is one way to determine efficiency.

Of course if we add magical zero-loss reactances, then your assumptions are correct. I'll take a box of those, if you really have them. :-)

73 Tom

That's what I was thinking.

I seem to recall the IF was up around 3 MHz. If that is the case, it will be very easy to rewind the transformer or substitute a TV set 4.5 MHz sound IF transformer with a little extra padding capacitance.

This subject is fascinating to me, but the antenna you posted is the only one I've seen.

Frankly, I wouldn't do it that way at all. I think it is a design fraught with potential problems for any possible small benefit in gain.  (Notice I won't use the myth or commonly abused "capture area".) The high feed impedance on ~50 MHz is a real issue, as is getting phase and current correct. 


A regular dipole at reasonable height over reasonable earth has 8-8.5 dBi gain. So what you are saying is you have 0.5-3 dB gain over a dipole. It is VERY easy to lose that much with design errors when dealing with stubs and matching systems.



A basic halfwave dipole at reasonable height over reasonable earth is 8-8.5 dBi. It would, of course, depend on ground losses.

I'd probably look at what I wanted to hear, and plan something around that.



It sounds like they really need a few good standard antenna designs with a reasonable matching systems. Frankly, for a single band antenna, I'd use a Q-section for matching and 1:1 choke balun. I'd stay away from transformers unless I knew the actual loss. You are using a primary-secondary transformer, this means the core will play a considerable role in efficiency. Think about this, on 160-20 meters I use a 2 turn to 5 turn transformer for 450 ohm Beverages to 75 ohm line.

You might consider a Q-section of the geometric mean of the antenna and transmission line impedances, and then just a simple 1:1 common mode choke with ferrites.

He probably should model the exact antenna.

If it is an elongated loop with large length compared to much less than 1/4 wave width, it will have maximum radiation (just like a folded dipole) when fed on the long side.  It's only when wire spacing is large, approaching 1/2 wave or more,  it can significantly null the horizon. His proposed loop is only 1/2 wave wide on ten meters, so it is pretty much a fat folded dipole on 20 and down.

If you are planning on a multiband doublet, like a 130 ft antenna fed with ladder line, it will only have maximum radiation broadside on 80-40 meters.

If you are planning on a fan dipole or trap dipole, it should have maximum radiation broadside on most bands.