Tag Archives: Barry (KU3X)

Accessories, Antennas, Guest Posts, News, Portable, Reviews

Barry reviews the RigExpert AA-650 Zoom

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Many thanks to Barry (KU3X) for sharing the following review originally posted on his website:

Product Review: RigExpert AA-650 Zoom

by Barry G. Kery, KU3X

If you are building a ham radio station, whether it be a contest station, a station for working DX or just daily rag chewing, this may be the tool you need to help you maximize your signal.

The AA-650 Zoom is a very user friendly antenna analyzer. It is super easy to navigate through the menu to choose what task you want the analyzer to perform.

Let’s start with frequency range. This unit will cover from 100 kHz up to 650 MHz. To get accurate readings, you must enter three factors. You must enter, “Frequency, span and sampling points. “  Here is one of many areas where the AA-650 Zoom shines and that is, “Sampling Points.”

When you sweep a frequency range, whether it’s just the 20 meter band or maybe sweep from 7000 kHz to 30000 kHz, sampling points have a direct impact on the results.

Antenna analyzers do not take a reading one Hertz at a time. They take a reading at numerous points within your sweep range. You can select how many sampling points you want to use. The 650 Zoom gives you 5 options. They are 20, 50, 100, 250 and 500 sampling points.

Let’s say you want to sweep from 7000 kHz to 30000 kHz, like the usable frequency range of a 40 meter off center fed antenna. If you choose to use 50 sampling points, the 650 Zoom will take a reading at every 460 kHz in that range. Once the sweep is finished, the analyzer takes an average and fills in the display with an SWR curve. So it kind of guesses what’s between each point.

Now take that same frequency range but sweep it with 500 sampling points. The 650 Zoom now takes a reading at every 46 kHz.  Remember one thing: the more sampling points you use, the slower the sweep but the higher the accuracy. For single band use, I like to use 100 sampling points.

Most of the time, that’s all you need. But let’s say the antenna you are testing has some quirk at a given frequency. If your sampling points are set too low, your sampling points may not be close enough to detect the problem. So now the analyzer will not know there’s an issue and fills in the display with an average reading.

There are two ways to setup the analyzer for a frequency and range. To the left shows where you can manually enter the center frequency and the span of the sweep. Press the, “Frequency key” on the keypad to access this feature. Within that display, to the far left you will see meter bands. If you press the, “F key” on the keypad, a band will be highlighted. Use the up / down arrow keys on the keypad to select your band of choice. When you let up on the, “F key” the analyzer will program that band with a predetermined span.

The picture on the right shows yet another super easy way to set up the analyzer. To access this screen, press and hold the, “F key” and then press the zero key on the keypad. The rest is easy. Pick a number that corresponds to the band you want to check.

Top picture shows an SWR curve of my 40 meter beam. This reading was taken from my shack. Take note of the bottom of the display. The analyzer lets you know what the minimum SWR is at a given frequency. On the top of graph, the SWR is shown in relation to the pointer.

The top right picture shows the SWR of my 20 meter beam at a given frequency. You may find this feature useful for adjusting a manually operated transmatch or adjusting the tuned inputs of your home brew amplifier. On the bottom of the display, it shows return loss at 14150 kHz.

When you sweep a frequency, you can save the SWR plot in any one of the 99 non-volatile memory slots so you can retrieve them at a later date.

If you want to check more than one frequency at a time, like on a tri band Yagi or an off center fed antenna, the AA-650 lets you pick up to 5 different frequencies to check at one time.

Shown below are return loss figures for a low power 4 to 1 Guanella Current Balun. The balun was designed to be used from 80 to 10 meters. The sweep is from 2 MHz to 30 MHz.

Let’s talk OSL Calibration…

Using Open, Short, Load calibration is a way to cancel out your transmission line so you can take a reading of your antenna like you are attaching the antenna analyzer to the feed point of the antenna. Let’s take a 100 foot length of RG-8X as our coax used for testing antennas. Hook the coax to the 650 Zoom and run OSL Calibration. Once you do that, it’s like the coax is transparent. Continue reading Barry reviews the RigExpert AA-650 Zoom →

Antennas, Guest Posts, News, Portable, QRP, Reviews

Barry reviews the PAC-12 portable antenna

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Many thanks to Barry (KU3X) for sharing the following guest post originally posted on his website:

Product Review: PAC-12 Portable Multi Band Vertical Antenna

by Barry G. Kery, KU3X

 

I am always on the hunt for a better mouse trap. Dave, NB3R came across a great multi band vertical antenna for portable operating. It’s a, “ PAC-12 7-50MHz Shortwave Antenna “ found on AliExpress.com.

The PAC-12 antenna is designed to operate on any frequency from 6 meters down to 40 meters.

Numerous manufactures make multi band vertical antennas designed to be used for portable operating. Some have quality issues and others may have performance issues, or both? Any hunk of wire or aluminum will radiate if RF is applied to it, but how much will be radiated is the question.

When it comes to ground mounted vertical antennas, one major factor that effects performance is the ground radial field. The PAC-12 comes with a long ribbon cable that you will have to separate each wire and cut to a quarter wave length per band of operation. There are ten wires within the ribbon cable. The length of the ribbon cable is 18 feet. This is too short for 40 meters but perfect for 20 meters. I made four 35 foot long radials out of some wire I had laying around the shack. This will increase the performance on the 40 meter band as well as making a better match. Spread the radial wires out equally around the base of the antenna.  Since the radials are not elevated, they do not have to be tuned but it does make for a better match.

The antenna comes with a short stake that can be driven into the ground for attaching the ground radial crimp on to and attaching the feed insulator.

The stake is strong enough to support the entire antenna, even on windy days. The feed insulator has an SO-239 for connecting your coax. The feed insulator must be attached to the ground stake correctly. Make sure the writing on the insulator is on top of the SO-239 and the black portion of the insulator is attached to the ground stake.

So what makes this antenna perform better than most other commercially made portable vertical antennas? Answer, “the mast!”

Most manufactures, not all, use a tapped base loading coil to make the antenna resonant on numerous bands.  On a quarter wave antenna, the wire or aluminum closest to the feed point of the antenna is the current portion of the antenna and the current portion does the most radiating. Continue reading Barry reviews the PAC-12 portable antenna →

Antenna Tuners, News, Reviews

Barry’ review of the ATU-10 QRP Antenna Tuner

18 Comments

Many thanks to Barry (KU3X) for sharing the following guest post originally posted on his website:

ATU-10 from Banggood.com

by Barry (KU3X)

There are times I find myself in need of an ATU. One example is when I use my half wave end fed 40. I can not always erect this antenna in the clear. I did purchase the LDG Z100 Plus 705 with interfacing cable. The unit does as advertised but I am not impressed with its performance. My biggest complaint is, when interfaced and the IC-705 tells the LDG to tune and it does not know the antenna is matched and resonant, the LDG adds capacitance and inductance which actually raises the SWR. It’s too dumb to go into bypass. I resolved this by not using the interface cable. Now I only tell the LDG to tune where needed. Most of the time I turn the LDG off by toggling between bypass and tune using the button of the front of the unit.

Size matters to me and the LDG ATU is too big. Another downside is it uses SO-239 connectors instead of BNC connectors. Everything I have relating to QRP operating uses all BNC connectors, including my home brew two position antenna switch. I do want to get my hands on an Elecraft T1 ATU but Elecraft can’t get the parts from the manufactures to make them. So the hunt was on for a small ATU with internal batteries and BNC’s instead of the dreaded SO-239 connectors. Here is what I came up with.

I ordered the above pictured ATU-10 from Banggood.com. I have also seen them posted on Amazon.com. They can be found on eBay as well. I did not provide a link for ebay because some ebay adds are dated. There is a very good demo posted on YouTube. Here is an overview of the ATU-10 [PDF].

My ATU-10 arrived 11 June 2022. Here are my findings:

The package contained an Allen wrench and a USB cable for charging the battery as well as for updating the firmware. The package DID NOT include the interface cable for the Icom 705 nor did it included any paperwork…….no manual! My battery showed about half charged and firmware version 1.4 was installed. If you forget to charge the battery and go on site with a dead battery, you can supply power to the ATU-10 via the USB charging cable. You may have to give it a few minutes for the batteries to take a little charge, but from that point on just leave keep the ATU-10 connected to the USB cable.

The needed interface cable is nothing more than a stereo audio cable with 1/8″ male plugs on both ends. But, the ATU works without the interface cable, it’s just not controllable from the radio. As for the matching, I can say it works as good as or as bad as my LDG Z-100 Plus. Where ever the LDG provided a match, so did the ATU-10. On 80 meters where the LDG did not do so well, neither did the ATU-10.

I first tried the ATU-10 without the interface cable. I just sent a carrier from the radio and the tuner went into the tune mode. It’s that simple. It takes anywhere from 2 to 5 seconds to find a reasonable match.

To use the ATU-10 with the interface cable, there is the setup procedure. Hook up all of the cables, including the interface cable to the IC-705. Now turn the ATU-10 on. Once booted, turn on the IC-705. Go into the, “Function” screen and tap the, “tuner” icon. You are ready to go. You do not have to change modes to have the ATU-10 go into the tune mode. In any mode on the radio, like SSB, just key the mic and the tuner will tune. Give it a second or two and you are ready to go. Change bands and key the mic, same results. I lost communication between the radio and the ATU-10 when I went to 80 meters. I have no idea why? I just turned the radio off, then back on and everything was reset…ready to go.

When I received my ATU-10, I noticed all of the hardware was not that tight. I retightened each nut and Allen screw.

User group for the ATU-10 and the ATU-100.

Pros:

  • Size…the ATU-10 is small enough to carry in your shirt pocket ( 5″ x 2-3/4″ x 1″ )
  • Antenna connections… BNC. All of my cables used when I set up portable use BNC connectors.
  • Power source ….the ATU-10 has two internal rechargeable batteries so no external power source is needed. Since the ATU-10 uses latching relays, the only power that is needed is for the display. The display has a time out timer and the ATU will turn off after 30 minutes on non use. The ATU will last you for months on end before needing to be recharged.
  • Display… the display shows SWR, power out and the state of charge for the internal batteries. It also shows what firmware is installed. The display will fall asleep after 5 minutes of non use. If power is applied, the display will wake up. The entire ATU will turn off after 30 minutes of non use.
  • Bypass mode (simply turn the ATU-10 off)
  • Construction…..the ATU-10 is built inside of a solid metal enclosure.

Cons:

  • Loss of communication….more than once communication was lost between the radio and the tuner. Easy fix by turning the radio off and then back on but this is very inconvenient.
  • No manual…..not even a little sheet of paper showing the specs. Whatever you need to know can be found on this site: ATU-10 info at GitHub.

Final notes:

For the price, it think this is a great buy. It does exactly what I want it to do and provides a reasonable match to make the radio happy. You can use the ATU-10 with any radio at power level of 10 watts or less. It’s a perfect size for backpackers. I don’t think the interfacing between the radio and the ATU-10 is all that importable. I myself choose not to use the interface cable. Since the tuner will go into a tune mode if the SWR is too high, that’s all that is really needed.