Kenwood LF-30A low pass filter ,question about ???

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WARLOCK
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Kenwood LF-30A low pass filter ,question about ???

Postby WARLOCK » 07 Feb 2017, 15:48

i have just bought a kenwood lf-30a low pass filter can this filter be fitted either way round as there is nothing to say which way round it should be fitted .???

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Re: Kenwood LF-30A low pass filter ,question about ???

Postby Admiral » 07 Feb 2017, 16:02

Yes, you can connect it either way around, this, as with most external low pass filters have no gender. Did you obtain it because you have an Ofcom grievance lodged against you? I don't see the point otherwise.
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Re: Kenwood LF-30A low pass filter ,question about ???

Postby kilimax » 07 Feb 2017, 16:10

Admiral wrote:Yes, you can connect it either way around, this, as with most external low pass filters have no gender. Did you obtain it because you have an Ofcom grievance lodged against you? I don't see the point otherwise.


An unfiltered Zetagi, RM or similar amplifier would be one reason which would then avoid Ofcom grievance in the first place.
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Re: Kenwood LF-30A low pass filter ,question about ???

Postby WARLOCK » 07 Feb 2017, 18:49

No Admiral ,i bought it for a £1 at a car boot sale so i thought i would give it a try anyway it will not do any harm to have it in line me thinks ,

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Re: Kenwood LF-30A low pass filter ,question about ???

Postby Otter » 07 Feb 2017, 20:23

They are very good filters (I've looked at four, and compared them to other makes on a vector network analyser) and low loss. I keep one inline both at home and in the car to avoid giving problems.
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Re: Kenwood LF-30A low pass filter ,question about ???

Postby ChrisMagpie » 07 Feb 2017, 21:47

WARLOCK wrote:No Admiral ,i bought it for a £1 at a car boot sale so i thought i would give it a try anyway it will not do any harm to have it in line me thinks ,

They were over £50 new, so a great bargain there!
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Re: Kenwood LF-30A low pass filter ,question about ???

Postby andymuza » 07 Feb 2017, 23:09

I have one as well, great filter but in this day and age they are about obsolete in amateur radio as most radios have a built in LPF.
No harm having one though just in case.
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Re: Kenwood LF-30A low pass filter ,question about ???

Postby ghost123uk » 08 Feb 2017, 08:58

I love car boot sale electronic gear bargains. Can't wait for them to start up again :)
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Re: Kenwood LF-30A low pass filter ,question about ???

Postby owza » 08 Feb 2017, 11:54

Not so good on 6m ;)

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Re: Kenwood LF-30A low pass filter ,question about ???

Postby andymuza » 08 Feb 2017, 17:03

owza wrote:Not so good on 6m ;)


MMM, I wonder why that is.
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Re: Kenwood LF-30A low pass filter ,question about ???

Postby ballo » 11 Feb 2017, 09:17

Cut off of this kind of lowpass filters is just above 35 Mc ( http://www.amateurtele.com/index.php?artikel=85 ) to supress harmonics of the transceiver to avoid such as TVI and radio interference. Anything below 35 Mc will be not supressed.
Harmonics are unwanted multiplied tx signals like tx= 27.000 Mc so 54 Mc (2x) , 81 Mc (3x) etc.

There is also a exactly same Lowpassfilter with the name Ham International on it , same specs.Maybe more.
I read a test in the early 80's when you ground the cover with the case that the specs are even slightly better.


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