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Author Topic: LDG RT-11 vs. Icom AH-4  (Read 674 times)
KA4KOE
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Posts: 324


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« on: July 23, 2003, 08:50:52 AM »

Simple question...which remote tuner is the best all around, ie build quality, SWR's matched, etc. I want to operate 160m thru 6m. I understand the AH-4 will tune 160m if you use a long enough line.

Tnx

Philip
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W4GLM
Member

Posts: 6




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« Reply #1 on: July 23, 2003, 09:05:15 AM »

Philip, I have used the AH-4 for several years.

I run about 15' of RG-213 to the coupler and one leg

of a 500' loop to one side of the coupler and the

other leg of the loop to the coupler ground.

Simply stated it works "GREAT", All bands 160 - 6

Using an Icom 746 or an 706 MKIIG. My loop is only up

some 40' and primarily a cloud burner (NVIS) I work

my share of Stateside / DX contacts.

It couples fast and tunes 1.5:1 or lower.

I could not ask for more, I remove it and use in my

P/U at times with a 102" whip and a Hustler Ball Mount

on the rear or a Diamond Tool Box, works F/B there

also. Never tried 160 mobile but tunes 75 fine.

One of the better investments I've made in Ham

Radio since 1965.

Hope this helps a little in your decision making.
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W4TME
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Posts: 299




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« Reply #2 on: July 23, 2003, 09:09:16 AM »

I don't have much experience with the RT-11, but I have used the AH-4 extensively.  If you have an Icom rig, using this tuner is a breeze.  I have a 92 foot dipole (46' each leg) fed with about 75 feet of 450 ohm ldder line.  The tuner is at the end of a 150' control cable.  I can tune 160-6 meters with a max SWR of 1.4 on 6 meters.  I am running about 100 watts through it.  It has endured ice storms (the antenna did not), a lot of rain and the hot & humid weather in Central NC without a single problem. If you want some good info on the AH-4, check out http://www.hamoperator.com/ah4/

Good luck!
73 de W4TME
-Tim
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K0BG
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« Reply #3 on: July 23, 2003, 09:41:12 AM »

There are basically two types of autotuners out there. One is designed for coax matching, the other for long (or short) wires.

The coax units do not have the range to match much more than a 10:1 SWR or so. The LDG and the AlphaDelta units are examples of this type, and only have coax fittings.

The SGC and AH-4 are examples of the other type. I refer to them as HV (high voltage) types because the output connecter is just that; a HV connection. The units will match 100:1 or more in most cases.

Alan, KØBG
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AA4PB
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Posts: 14390




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« Reply #4 on: July 23, 2003, 09:57:35 AM »

Alan has hit the nail on the head again. I believe SGC uses the terminology of an "antenna tuner" vs. a "matchbox" or some such thing. They have some good stuff on their web page regarding the differences. Basically, an "antenna tuner" is located close to the antenna (or connected to it with an open-wire or other very low loss feed line) and has a wide impedance matching range. It is designed to tune a wire antenna on multiple bands.

A "matchbox" is designed to reside near the radio and has a much more limited impedance range. It is designed to take a coaxial feed line with a reasonable SWR (well under 10:1) and present a nice 50-ohm impedance for the transmitter.

To my knowledge, Icom, SGC, and Alinco are the only well known amateur suppliers who have "antenna tuners". There are some others making commercial units for boats and the military. The rest are "matchboxes".
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Bob  AA4PB
Garrisonville, VA
AA4PB
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Posts: 14390




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« Reply #5 on: July 23, 2003, 10:07:53 AM »

I'll also add that IF you have an Icom rig with the built-in tuner control and you plan to keep it then the AH-4 is a good choice. The SGC tuners are designed to work with any radio however (you'll need an add-on box to make an AH-4 play with a non-Icom radio). If you don't have an Icom or think that you might someday want to use a different radio then the SGC is the better choice.

I have an SGC SG-230 and the nice thing is that I can simply connect any radio with an output between 3 and 100 watts to the coax, key up, and the tuner tunes. I've used it with the IC-756PRO, the IC-761, the SG-2020, and a variety of QRP rigs.
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Bob  AA4PB
Garrisonville, VA
KT8K
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Posts: 1490




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« Reply #6 on: July 23, 2003, 11:34:58 AM »

Could someone summarize the differences in insertion loss between the models/makes?  I run QRP and usually avoid tuners, but with all these bands ...
thanks - Tim, KT8K
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AA4PB
Member

Posts: 14390




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« Reply #7 on: July 23, 2003, 11:46:37 AM »

I don't think the insertion loss of any properly installed tuner is going to be very significant. Now the antenna efficiency can make a huge difference. If you have a lot of ground losses or a short antenna (in terms of wavelength) you can introduce a lot of loss.

Similarly, trying to feed 100 feet of RG58 with an SWR on it of 10:1 can introduce a lot of loss. Remember, if the tuner is located at the radio then it is doing nothing for the SWR on the feed line.
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Bob  AA4PB
Garrisonville, VA
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