interfernece rejection on flashers

[mww24]

My buddy and I were out sat. nite fishing in the same porty. He has a marcum lx3 and I have a VX1. no matter how many times i pushed my IR button I could not get the screen to stop dancin. Whereas his was workin fine once he found the right IR setting. Last year we used the same two flashers and they both worked fine next to each other. Does anyone have any thoughts on why they dont work next to each other now? It was very frustrating. Thanks for the input.

[DTro]

The ability to reject interference is based on different varying factors.

How close the transducers are together

Where the transducers are placed in relation to the water line/ice

Depth of water

Bottom Content

Gain Setting

Other flasher in close proximity

More times than not, it just takes fiddling around with them to get the right combination.

There are times however when all conditions come together that you just can't make it work. Usually this happens with deeper water and hard bottom

[NCLaker]

Does the VX-1 work fine when you have it on and no other flasher is on next to you? It should work with the gain down to 0-2 usually. I had an LX-3tc, Had to turn up the gain quite a bit to see my lure, and as a result I could not knock out the interferance from a nearby FL-8. Ended up having to send in to Marcum to fix. Not sure if the gain/interference problem was caused by the same malfunction or not. They ended up replacing the ducer and doing something to the head unit.

May want to give there service a call if you can't figure it out.

[Deitz Dittrich]

Like Dtro said, check start playing with how far down the hole you have the ducer.

The biggest factor I have seen is water depth combined with bottom content. The harder the bottom and the deeper you are fishing, the more issues you will have.

[Caleb S]

Does the VX-1 work fine when you have it on and no other flasher is on next to you? It should work with the gain down to 0-2 usually. I had an LX-3tc, Had to turn up the gain quite a bit to see my lure, and as a result I could not knock out the interferance from a nearby FL-8. Ended up having to send in to Marcum to fix. Not sure if the gain/interference problem was caused by the same malfunction or not. They ended up replacing the ducer and doing something to the head unit.

May want to give there service a call if you can't figure it out.

How deep were you fishing and how big of a jig were you using?

[mww24]

Thanks for the input. Yeah i had the gain up to about 4. I was in 33 ft with a small thin jig. That could very well have been the problem. when we used them together last year we were in 14 fow with spoons. only had the gain a little above zero then. Oh well. I still caught all the fish. he got skunked.

[broman]

Check his gain. He might have it cranked way up and that will be overpowering your unit. With his unit down to a low setting you will have a better chance at getting rid of the interference. I had the same issue fishing with my cuz and his FL-18. I sold the VX-1 and got a LX3 for the extra power. The extra power helps me knock out his units interference. Basically, whoever's got the loudest radio gets to hear their music.

[Dave]

I don't believe that's true, broman. I believe flashers output the max power and the sensitivity (gain adjustment) is adjusting what the receiver displays.

[PerchJerker]

I don't believe that's true, broman. I believe flashers output the max power and the sensitivity (gain adjustment) is adjusting what the receiver displays.

Dave is correct.

[broman]

I would have to disagree.

Here is an explanation of gain from the a wiki entry I found.

Quote:

In electronics, gain is a measure of the ability of a circuit (often an amplifier) to increase the power or amplitude of a signal. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. It may also be defined as the decimal logarithm of the same ratio.

Below is what I found in the Vexilar manual which also backs up my explanation.

Quote:

GAIN

Gain controls the amount of amplification applied to the return sonar signal. Think of gain

as your volume control. You turn up the gain to see more of what’s below. You turn down

the gain to see less of what you don’t want to see. The goal is to fi nd a gain level that

shows you as much real information as possible, without displaying stray signals of clutter

and interference.

If you really wanted to know for sure you could put a multimeter in between the battery connection and see how the amperage draw changes when you change the gain.

[broman]

I just tested the amp draw and it didn't change. So... I'm probably wrong. My electronics knowledge has been lost throughout the years. Why call it gain if it doesn't adjust you power. Can someone chime in?

[JIM C]

Your quote:

GAIN

Gain controls the amount of amplification applied to the RETURN sonar signal.

The key words here are "return sonar signal". All common fishing sonars send their max rated pulse wattage to the transducer, and every time that transducer clicks it's sending a sound wave off into the water. When the sound signal hits something and is returned, the unit will then process that signal and display it according to your sensitivity or "gain" settings.

[kujo]

The gain you are refering to in electroincs does not have the same meaning in ultrsonics. When working with ultrasonic technology the lower the better. The higher the gain the more "noise"/false echos are returned. On most transducers, the output/wavelength is always running at the same frequency, while the gain control is reading the returns. By turning up your gain you are looking at that noise that you otherwise want to tune out. Hope that helps.