| W1NEJ |
Rating:      |
2012-02-20 | |
| A Nice Little Box |
Time Owned: 0 to 3 months. |
This is a great little tuner. I got it after I switched from an AL-1200 linear to my Elecraft KPA-500 solid state linear (another sweet little box).
It has worked very well to clean up what I would call minor SWR issues (not worse than 3:1 SWR at the band edges) of my two antennas, which were OK with the AL-1200 but I wanted to run the solid state amp with very low SWR.
But I cannot say that this tuner will work with any antenna or random length of wire. It is advertised to work with coax fed antennas, which should be more or less resonant to begin with.
The tuner has 16 relays, 7 of which switch capacitors to ground and 7 of which control the inductors to be in or out of the circuit.
The inductors are wired in series between the input connector and the antenna relay.
These are shunted by the 7 inductor relays. The relays are switched in a binary progression that starts with the lowest value of inductance, and works up to the highest value, and so on, in a binary progression, which gives 127 different values of inductance that can be switched in with a high degree of resolution since they are toroidal inductors that are wound with from 2 turns to many turns of wire, but I do not know the value of the inductors.
Each capacitance that is switched to ground is made up of 4 500 volt 5% mica capacitors connected in series. This gives each capacitor a 2000 volt rating, so don't worry about the comment that was made elsewhere that the capacitors are not big enough.
The combined values of each bank of 4 capacitors are 10, 20, 40, 80, 160, 320, and 640 pf. These are switched to ground by the 7 relays in a binary progression that starts with the lowest value, and works up to the highest value, and so on, in a binary progression, which gives 127 different values of capacitance that can be switched in with resolution to 10 pf.
Besides the 7 inductor relays and the 7 capacitor relays there are two additional relays. One of these is the hi/lo z relay. This relay switches the capacitors so they are connected to the input connector or the output connector so it is possible to tune antennas that are either more or less than 50 ohms, and antennas with either leading or lagging "j".
The last relay is the antenna relay that will switch the antenna tuner to two output connectors. Since I use a DX Engineering antenna switch located out doors to switch between my antennas, I use position one on the antenna tuner to feed the DX Engineering antenna switch, and position two to switch the antenna tuner to my dummy load.
The antenna tuner has not failed to find a match on my 40 meter OCF on 40, 20, 10, and 6 meters, and my 17 meter dipole. Of course, these are not difficult antennas to tune, and as stated I cannot vouch for this tuner using any other style of antenna or random length of wire. It tunes quickly, and the memory tune function works as advertised. When doing a full tune, you can hear those 14 relays clacking, but after it learns a frequency it is just a quick click of the appropriate relays.
LDG uses a very clever way to control and see what is going on in the tuner that once you play with a few times is very easy to learn. And you can press and hold the "function" button and then press the "tune" button to see the position of all the relays.
The tuner is in a nice metal box that has a good fit and finish, and the circuit board is very well made with mostly surface mount parts. This is not something that I would want to try and fix unless it was one of the wire lead components such as a coil or mica capacitor, which are installed through-hole on the circuit board.
As of this writing, I would recommend the AT-600 to anyone with a lower power linear, but be sure you do not exceed its power ratings if you use a continuous mode of transmission. |
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| W4FCC |
Rating:  |
2011-12-16 | |
| Nice idea, but... |
Time Owned: 0 to 3 months. |
I just took delivery of this tuner from Cheapham to replace an MFJ 962-C for use on a center fed doublet-- the MFJ tunes it just fine but I thought I'd join the 21st century and get an autotuner. From the tuner there's a 15' jumper to a DX Engineering balun, then their 300 ohm window line (92.7 feet, as they recommend) to the feedpoint.
The MFJ is a bit touchy on the low end of 80, but it DOES tune the antenna. I just spent a half hour with the LDG tuning with 10W, and the ONLY place this thing will match is 40 meters. Maybe it's defective-- since I dont have a known good one to test with I can't say, but this is a huge disappointment and it's going back for a refund. Hopefully I can win the argument over that silly restocking fee. |
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| KG0MN |
Rating:      |
2011-11-05 | |
| Love this unit |
Time Owned: 3 to 6 months. |
| Prior to picking up a refurbished AT600 PRO from Cheapham.com I was using the MFJ 989D, if I had of know how well this little unit worked I would have purchased one a long time ago. I am using it with my SB-200 and it works perfectly. Just remember to go to AM and use reduced output to get the initial tuning done and then switch to full power 600 watts or less and you should be good to go. |
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| WN6J |
Rating:      |
2011-08-05 | |
| GREAT TUNER |
Time Owned: 0 to 3 months. |
| When I got my Yaesu FT-450AT, with the built in tuner last year, I thought who needs a tuner, and sold my MFJ on ebay. Did I have it wrong! After figuring out the problem was with the tuner and not the antenna I purchased the LDG-AT 600Pro at HRO in Oakland. Tunes quickly and works well with my Ameritron ALS-600. |
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| N4NDX |
Rating:      |
2011-08-02 | |
| Great Tuner |
Time Owned: 6 to 12 months. |
I`ve only had this tuner for 8 month but I have made DX contacts with more than 40 countries and used 600 Watt in most cases and it works great for me, easy to use with no complication what so ever. Hope it continues to do a good job.
73`s de David/n4ndx |
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| AE5X |
Rating:   |
2011-05-22 | |
| Smoked...at only 500 watts |
Time Owned: 3 to 6 months. |
After a 20-minute run during the ARRL DX Contest, an aroma in the shack left no doubt that some electrical component was hotter than hell. It turned out to be L3 in the AT600Pro – charred black and smokin’.
An exchange of emails with LDG resulted in a replacement inductor a few days later but I knew I’d need to make changes to the antenna or I’d simply cook this inductor as well. The addition of 7 feet of RG8X going from the tuner to the outdoor balun fixed the problem. The tuner now ran cool on 40 meters at full power.
But not on 20 meters! The problem had now QSY’ed and a few CQ’s at 500 watts on 20 meters resulted in two charbroiled inductors in the photo above.
I realize that my antenna is asking a lot from a tuner, however LDG’s 100-watt tuner handled things perfectly at 100 watts, yet the 600-watt tuner can’t at 500 watts.
For a moment I considered contacting LDG and asking if they’d let me return the AT600Pro and pay the difference for their 1000-watt autotuner but I doubt that tuner would work either, given the amount of heat obvious in the 600-watt version.
In the meantime, a Ten Tec 238C is on its way here. Not a cheap item by any stretch (and manual to boot) but a quality piece of gear with the highest rating in a QST review that measured losses & efficient of several popular high-power tuners a few years ago (Feb 2003).
Photos of the tuner's internal's are at:
http://www.ae5x.com/blog/qro/review-ldg-at600-autotuner/
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| KH6TA |
Rating:      |
2011-04-15 | |
| Quick & Reliable! |
Time Owned: 0 to 3 months. |
I recently bought this tuner, and have had an LDG AT-7000 and then an LDG AT-200Pro for about a year now.
I moved the AT-200Pro over to my IC-706Mk2G and put the AT-600Pro on my IC-7600/ALS500M. Keep in mind you can go up to 250W MAX on the AT-200Pro and 700W MAX on the AT-600Pro, and they also read PEP or RMS, which is great!
The AT-600Pro works great! I'll NEVER go back to manual tuning. Takes a little "hands-on studying" to get up on all the settings, etc. but like my AT-200Pro, the AT-600Pro is a breeze to use, and both have many great features. A super value at the price these sell for!
GO BUY ONE, YOU'LL LOVE IT!
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| WD4ELG |
Rating:      |
2011-04-09 | |
| No issues |
Time Owned: 3 to 6 months. |
| Took a few minutes to get used to the Auto/Manual tune option. No other problems. Use it with a THP 600W amp. |
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| KK2DOG |
Rating:      |
2011-04-09 | |
| Sweet ! |
Time Owned: 0 to 3 months. |
Rig: IC-706MKIIG
Amp: Ameritron AL-811
Antenna: Antron-99
I use this set-up for 10,12,15,& 17 meters with about 500 watts output and this tuner works GREAT!
A quick push of the tuners button will get the
standing wave down to where you want...anywhere between 1.1 and 3.5. Please keep in mind that I'm using a "CB/10-Meter" antenna, and your mileage may vary. The LDG AT-600Pro tuner is a GREAT tuner, and it matches PERFECTLY with an Ameritron AL-500, AL-600, or AL-811 amplifiers. Two thumbs-up from the DOG. |
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| KF5CZG |
Rating:  |
2011-04-04 | |
| Burnt up again |
Time Owned: 3 to 6 months. |
This has happened twice (in 6 months) to me using a S9 vertical antenna...Picture is on my QRZ site:
http://www.qrz.com/db/K5USF
Now, I have to spend the time to ship it back again!
K5USF (aka KF5CZG) |
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