Bencher YA1 Low Pass Filter

[Drifter]

Is it normal for a low pass filter to get warm to the touch when operating I have a Bencher YA1 inline. I am running less power than what the filter is rated for, connections are tight and my SWR is below 1.5.

Thanks

 

[dudmuck]

This lowpass filter might have an insertion loss of 0.2dB at the most.
Thats the same as losing 4.6% of your power.
For example if you were running 1500 watts, that would be almost 70 watts of power absorbed by the filter.
If the insertion loss was 0.1dB, then it would be 30 watts.

Also, if you have high harmonics, its possible it could absorb some of that harmonic energy rather than reflect it back to your amplifier.

 

[Captain Kilowatt]

What are you running ahead of the filter? If it's getting warm it must be trying to deal with a horrendous amount of harmonics and crap.Normally a LPF should not even get warm at all during normal conversation.

 

[Drifter]

This lowpass filter might have an insertion loss of 0.2dB at the most.
Thats the same as losing 4.6% of your power.
For example if you were running 1500 watts, that would be almost 70 watts of power absorbed by the filter.
If the insertion loss was 0.1dB, then it would be 30 watts.

Also, if you have high harmonics, its possible it could absorb some of that harmonic energy rather than reflect it back to your amplifier.

So is the insertion loss watts given up as heat?

 

[Moleculo]

I burned up one of those Bencher YA-1 filters a long time ago. I had it on a system I was using legal limit with and tuning bands the antenna was not resonant at. It couldn't handle the voltage present on the line and burned up. I'd say it was pretty hot... LOL

 

[W5LZ]

No, a low-pass filter shouldn't get hot, at least not overly 'warmish' at most. If it's dissipating enough 'stuff' to get that hot, I think I'd take a look at the rest of the system. No real idea of what might be causing it, so good luck.
- 'Doc

 

[Drifter]

No, a low-pass filter shouldn't get hot, at least not overly 'warmish' at most. If it's dissipating enough 'stuff' to get that hot, I think I'd take a look at the rest of the system. No real idea of what might be causing it, so good luck.
- 'Doc

No it does not get hot... Just warm to the touch with 1KW average watts into it. I looked at the specs again Its rated for 1.5 KW continuous and I am putting 1000+/- continuous watts into the thing. So I guess it is a combination of Harmonics and running it close to its limits.

I have a ICE LPF that has a higher input rating. I am going to put it inline and see what happens.

 

[W5LZ]

After re-reading my post I think I'd better re-phrase is a bit. 'Warmish' is sort of relative. Anything you touch around here in the last couple of days has been at ~least~ 'warmish', it's been HOT. If you found a shiny silver dollar laying in the sun, you'd better let it stay there rather than dropping it in your pocket. Unless your pants are made of asbestos! Felt a few things on the desk and they were 'warmish', sort of. Not much of an excuse, but it's honest.
The power ratings for LPF are sort of like those for various other thingys. Sort of 'optimistic'. Running at something like 60% can be a bit 'much' at times. That power rating is based on max power from a typical signal, not really counting any 'extra' stuff it's filtering out. That 'extra' stuff is what the filter is dissipating since the good 'stuff' isn't affecting it, just goes right through sort of. That's not exactly true, anything going through the filter is going to affect it, just not as much (another sort of thing). A nice 'rule of thumb' is at least twice the power you use as a max rating.
Another thing is that 'Bencher' makes very nice 'keys/keyers', not exactly the best filters in the world. They do work, others, such as 'ICE' make ones that are not quite so 'conservative'. 'Over-kill' on their ratings is very nice for LPF. Oh well.
- 'Doc

(I just happen to have a 'Bencher' LPF, you want another one??)