The manual should be clear. All you do is leave the far end of the cable or stub open and tune the analyzer for minimum Z. That will be the frequency where it is an odd quarter wave long. If you make the stub for 49 MHz, the dip will be at 49 MHz. If it dips high, it is too short. If impedance dips too low in frequency, the stub is too long.

To check the half wave, do the same and dip at half frequency or short it and dip at full frequency.

If you are trying to check the element length, you would have to do it like a dipole.... or do it by formula. 

 

That's a VERY bad idea. I'd use twin lead or ladder line at a minimum, and preferably an air insulated stub.

 

Is there a link to the antenna?


Physical size is NOT related directly to capture area except in very special cases of standard high-efficiency antennas. Some virtually lossless perfect dish antennas, for example, have a known size to capture area relationship.

Capture area relates directly to GAIN and frequency. As such, it really has nothing to do with physical size with nearly all real antennas.

If both antennas are on the same frequency, an antenna ten miles long with 3 dB gain has less capture area than an antenna three inches long with 4 dB gain.

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

How fast aluminum goes away depends on the soil, how thick the wire is, and what else is in the ground system.

Aluminum certainly is not a first choice for soil contact.

I buy bare #16 copper buss wire. It lasts until something cuts through it, plus I can solder it.

If you look at the relay near the resistor, it looks like the armature has slipped out of place. This happens if there is a really hard drop on the amplifier. What happens is the G-force of the sudden stop overpowers the relay spring, and unseats the armature. This picture seems to show the armature as not seated flat in the relay frame:

http://i254.photobucket.com/albums/hh88/funbiz99/al572%20eham/P1040135.jpg

That could be an illusion, but it looks skewed.


Further along that line, it looks like the physical hit was hard enough the transformer under the tubes hit the chassis and chipped. I can see a definite chip in the core right where it would hit the chassis, and other signs of a pretty hard drop. (Actually the drop doesn't matter, the stop does.)

UNPLUG the amplifier, be SURE you unplug it, and you should be able to grab the relay armature and slip it back into place.

I would also IMMEDIATELY call the shipper and say it appears to have concealed damage, and be sure to save the boxes. I would carefully and closely inspect the amplifier for bent metal, like the chassis below the transformer where the G-force of the transformer might bend the steel bottom.

What shape are the boxes in, and where was it shipped from? You can tell a hard drop by the cardboard being crushed either inside or outside.

It should have been double boxed with foam supports on the amplifier. Were the inner foam cushions in place? Look at the packing closely.

That's odd. It does not seem to agree with the website.

The "last post from your IP within last 120 seconds" is annoying. 

When it comes up, I go back and wait. Then I click the post again. Then it says "duplicate post you already posted this". Then I check and it does not appear, so apparently I did not really post it even though eHam thinks I did.

So I just give up.

OK, thanks. I wondered what it was.

At what power level is 72 preferable or acceptable compared to 73? This is common?

I have troubles with spell check and eHam I guess. That should have been:

It is a different world today with import parts, plus use and abuse varies, so it is impossible to predict which way is better.

Generally, if I had instant-on type tubes, I would turn the amplifier OFF.

If I had a heater cathode tube of good quality, like an Eimac 8877, I'd most certainly not cycle filaments off and on very often.

OK, I know all about 88, 73, 10-4, 666, and even 69, but what is 72 and why do we need it?

I hear people saying 72 to each other today. Is that "regards" instead of "best regards"?

Thanks for the compliment, Vinnie.

You probably have a ground loop. This is very common with wiring errors on unbalanced audio lines, and sounds like you describe.

You might read this:

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

Read some of this and page links:

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

Especially this, which also applies to lightning:

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

What year was the amp made?

Tubes changed charateristics and started drawing more current. If it is an older amp without bias diodes, you might need to add about 3-4 volts of bias in the center tap lead. You can do that with a string of diodes.

Read this, especially 1, 2, and 4:

http://www.w8ji.com/ameritron_811h_572_amplifier_trouble_shooting.htm

Unless he has a really old poor receiver, an image is virtually impossible.

Almost everything beyond 1970 was a dual conversion receiver with a high IF frequency. Even in the 1960's, the SX101 and others used ~1700 kHz as a first IF. The image of that old stuff is 3.4 MHz away.

With broadband front ends, they had to move first IF's up to 5 MHz and higher.   This places the image 10 MHz away.

Rigs like Yaesu and others now use 40 MHz or similar for 1st IF, which places the image around 80 MHz away.  The low 455 IF's, while still used, always follow multiple narrow filters making any 910 kHz  image virtually immeasurable, because the image is filtered by multiple stages of crystal filters. The normal scheme is a low VHF first IF, 8 MHz second IF, and 455 third.

Highly unlikely the 455 factors into anything, unless the receiver is very old or a very cheap receiver with a oscillator tracking RF stage. That 455 image stuff pretty much went away in the 70's.

CB'ers on ten meters, however, are quite common. The truck stop on I-75 just north of me openly sells illegal 50-watt ten meter AM-FM radios to truckers. They are right out on the counter in plain sight. I can tune ten meters almost any time of the day and find truckers on ten meters, and the signals are NOT images. They are intentional, mostly AM, but sometimes FM.

73 Tom

It's nice to promote CW, but that seems like an odd frequency choice. They say:


On upper bands 18-28 up from band bottom is mostly extra class, with only 3 kHz for other classes. 160 meters, 1820 to 1828 is commonly used for DX work.   :-)

As for time:


It doesn't look like it is more than 1 hour on Wednesdays. Maybe you are hearing something else? What time are you mobile??

I don't know about the current manual, but the old manual guaranteed wrong assembly. It told people to tape the coax along a boom.

Since each boom is one conductor of a two conductor balanced transmission line, this is exactly like telling people to tape coax to one wire of an open wire line.

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

Before I installed a log, I'd make sure the feedline was routed correctly.

73 Tom