ICOM IC-7300 w/AH-4 Tuner and Long Wire

[TJPB]

Hey all....got a bit of an issue. So I just completed the install of an IC-7300 along with the AH-4 tuner and a 136' long wire antenna. So far, I have zero activity on the transceiver and haven't been able to receive anything really. If I turn the REF dB up to around 20 I can see the waterfall etc. but still no signals. I used Random Wire Antenna Lengths to determine 136'. It is connected to the AH-4 and then run up the side of the house and around the upper roof....it's around 35'-40' high.



This is my current setup:

ICOM IC-7300 TRANSCEIVER
ICOM AH-4 Antenna Tuner
LIGHTNING SURGE PROTECTORS (2)
ANTENNA WIRE
GROUND WIRE
GROUNDING RODS (3)
JUNCTION BOX
COAX
COAX CONNECTORS
COAX COMMON MODE NOISE FILTER
ROOF CABLE CLIPS
Various other connectors, chokes, sealant, accessories etc.

I've reset the IC-7300 back to factory settings and checked all COAX connections. I also have read the IC-7300 manual and made all the adjustments available. Still, no reception of anything. The spectrum scope also shows nothing. I've also installed the VHF/UHF antenna in the pics and it works perfectly. The HF install is of the same quality. Any help is appreciated! Thanks.

 

[TJPB]

136' of Dipoflex.... Dipoflex - Dipole and Grounding Cable - 100 meters (328 ft)

 

[AK9R]

A classic means of troubleshooting is to eliminate complication. With all the pieces of coax, lightning protection, filters, etc., you've added a lot of complication. Are you absolutely certain that each piece in the chain is actually passing a signal?

 

[AK9R]

Look at your antenna cable routing. The cable from the AH-4 goes in the top hole of the box with the lightning protection and comes out the bottom hole. Is that the cable that's connected to the radio?

 

[TJPB]

I wouldn’t call a lighting suppressor and coax noise choke complicated. Yes, all parts are working correctly.

 

[TJPB]

There are 2 boxes. One is the AH-4 and the other lightening suppression. The antenna wire does not enter the box with lightening suppression.

 

[prcguy]

This is not your main problem but 136ft of wire is not a great choice for that type of tuner as it is very close to 1/2 wavelength on 80m and 1/2 wave multiples on other bands. That will make for an extremely high impedance and very high voltages at the output of the tuner. Might be better to lengthen or shorten the main antenna wire by 10 or 20ft.

The AH-4 and any similar tuner needs a lot of counterpoise to work against and at least as much wire as the main antenna. If you don't provide a good counterpoise it will try and use your coax and control lines as the other half of the antenna and they will be hot with RF and will radiate just as much as the main antenna wire.

For your main problem of the radio not sensing the tuner, make sure all four wires from the tuner make connection from the tuner to the radio. At power up the radio should sense the AH-4 and bypass its internal tuner if all the wires are connected and the tuner is not broken.

 

[TJPB]

Okay, so if I shorten to 126’, how do I add the Counterpoise? Is that connected to the ground terminal of the AH-4?

 

[prcguy]

Its best to add two or more equal length counterpoise wires running opposite directions and the more the better. They do not have to be connected to anything but the ground connection on the tuner. If you have just one counterpoise wire that will make a dipole out of your tuner setup and that single wire will radiate. Two or more wires running opposite directions will cancel counterpoise radiation. You could run the wires opposite directions from the tuner on the wall or run them down to ground level and along the foundation, etc.

Okay, so if I shorten to 126’, how do I add the Counterpoise? Is that connected to the ground terminal of the AH-4?

Okay, so if I shorten to 126’, how do I add the Counterpoise? Is that connected to the ground terminal of the AH-4?

 

[kb5udf]

Quick test to make sure something weird is not going on with your IC7300. Hook it up to that VHF/UHF antenna, and see if you can hear any short wave stations and/or WWV. Your installation looks great, but there are numerous connections there and so troubleshooting is challenging. Assuming you get some type of Rx off of your VHF/UHF, I'd go back to your wire antenna, but this time, I'd go outside and hook up directly first, and then add in the other parts of the chain one at a time.

 

[Thunderknight]

What happens if you just run a 100 feet of wire out the window and the wire connected to the center pin of the SO-239? Don't transmit! But do you hear anything? Any noise? WWV on 5, 10 or 15 MHz?

 

[TJPB]

Its best to add two or more equal length counterpoise wires running opposite directions and the more the better. They do not have to be connected to anything but the ground connection on the tuner. If you have just one counterpoise wire that will make a dipole out of your tuner setup and that single wire will radiate. Two or more wires running opposite directions will cancel counterpoise radiation. You could run the wires opposite directions from the tuner on the wall or run them down to ground level and along the foundation, etc.

Everything I've read about the AH-4 says counterpoises are unnecessary...hence why this is a popular mobile setup. As my install needs to remain stealthy...it will be difficult running more wires around the house.

 

[TJPB]

What happens if you just run a 100 feet of wire out the window and the wire connected to the center pin of the SO-239? Don't transmit! But do you hear anything? Any noise? WWV on 5, 10 or 15 MHz?

I hear noise as it is. Sometimes I can get very faint signals...but can barely tune them in. I may try the direct connection next.

 

[TJPB]

For your main problem of the radio not sensing the tuner, make sure all four wires from the tuner make connection from the tuner to the radio. At power up the radio should sense the AH-4 and bypass its internal tuner if all the wires are connected and the tuner is not broken.

Right...but how does one verify it's bypassing the internal tuner? Is the 7300's reaction different when you press the tuner button when the AH-4 is connected vs. when it's just using the internal tuner? I checked the manual and it's not super clear.

 

[AK9R]

Everything I've read about the AH-4 says counterpoises are unnecessary...hence why this is a popular mobile setup.

The AH-4 absolutely needs a counterpoise. In a mobile installation, the structure of the vehicle is the counterpoise.

 

[TJPB]

The AH-4 absolutely needs a counterpoise. In a mobile installation, the structure of the vehicle is the counterpoise.

Okay....with a 136' antenna wire, what length counterpoise do I need and where is it attached? To the ground terminal on the AH-4 or? I thought a counterpoise wasn't necessary if you have an earth ground attached to the AH-4.

 

[AK9R]

Right...but how does one verify it's bypassing the internal tuner?

It's automatic. As soon as you plug the 4-wire cable from the AH-4 into the radio, the internal tuner is disabled.

Pin 3 of the 4-wire cable is 13 volts DC from the radio. Pin 4 is Ground for the control circuit. (In a 4-pin inline Molex connector like this, Pin 1 is at the pointy end.) You can use a voltmeter to verify that you have approximately 13 volts DC at the TUNER jack of the radio. If you don't have 13 volts at the TUNER jack, then an internal fuse may be blown. Then, you can go outside and verify that that 13 volts is getting out to the AH-4. If you don't have 13 volts at the tuner, then the control cable may be defective. Note, I have found with 3-party AH-4 control cables that the pins are sometimes not well-seated in the connector shell and they get pushed out slightly when you make the connections. All references to "13 volts" are approximate. The actual voltage will be pretty close to your power supply voltage.

When the radio sees a completed circuit from pin 3 to pin 4 at the TUNER jack, it assumes that the AH-4, or something similar, is connected and drawing power, so it disables the internal tuner.

 

[AK9R]

To the ground terminal on the AH-4 or?

Yes.

 

[jwt873]

Have you tried to listen for any local AM Broadcast Band stations? (Between .55 and 1.700 kHz) They are guaranteed to be strong. If you can't hear any then there is a problem.

One thing you might check.. (A friend of mine got caught by this).. Make sure the white mark on the RF/SQL ring (behind the volume control) is pointing straight up.. Too far to the left and you're reducing RF gain.. Too far to the right and you've turned the squelch on.

 

[TJPB]

Yes.

To be clear, the AH-4 ground terminal will have an earth ground connected....as well as a counterpoise wire connected. How long should the counterpoise be? I've read it needs to be 1/3 longer than the antenna wire?