[Fourlanders] 222 Bandpass filter needed

[Rogers, Ron]

Thanks, Brian. 
 
Does anyone know if someone has actually modified the military F Band
cavities up to 222 MHz and what it took to do that. IF you had to
lengthen the cans, that would be tough. If you can simply lengthen the
plunger, then maybe that would be easier. 
 
Robin,
Do you still have any of the 220 cavities ?
 

Ron  


WW8RR

________________________________

From: Brian McCarthy [mailto:rfacres at gmail.com] 
Sent: Tuesday, November 25, 2008 7:36 AM
To: Rogers, Ron; Robin Midgett
Cc: Bob Lear; fourlanders at contesting.com; Gary Bailey
Subject: Re: [Fourlanders] 222 Bandpass filter needed


I believe Robin, K4IDC, had quite some pile of 220 cavities that he was
trying to or helping to sell. I am not sure if any of those are still
available.

At Fair Radio they still have some of the F band dual cavities that
should be modifiable to 222.

See: http://www.fairradio.com/catalog.php?mode=viewitem&item=3872

They also have some Celwave 220 cavities.

See: http://www.fairradio.com/catalog.php?mode=viewitem&item=3886

I would be willing to donate toward whatever solution seems required.

Just my thoughts,
Brian
NX9O


On Tue, Nov 25, 2008 at 6:50 AM, Rogers, Ron <RR124640 at ncr.com> wrote:


	I don't know if I have anything here, Bob. But I will check.
	I will also research to see if there have been any articles
published about 220 filters and cavities, as such.
	
	Or maybe find an old 140 - 150 MHz VHF cavity and see if it can
be cut down to 220 size.  I'll bet even a tunable Hi-Q helical coil
filter design would work for this situation.
	
	Ron
	WW8RR
	
	________________________________
	
	From: fourlanders-bounces at contesting.com on behalf of Bob Lear
	Sent: Mon 11/24/2008 10:35 PM
	To: fourlanders at contesting.com; Gary Bailey
	Subject: [Fourlanders] 222 Bandpass filter needed
	


	This is regarding the recent problem with the WA4IOB 222 beacon
which
	has been shut down since the spur problem.  I ran into Gary at
the Stone
	Mountain hamfest and we discussed the situation.  He said a
filter will
	probably solve the problem and he has a network analyzer with
which to
	tune one if we can come up with a suitable filter for him.
	
	I thought I had one, but it turned out to be too high in
frequency.  I'm
	still looking in the mess I'm making while moving and losing
stuff left
	and right in boxes here and there!!  I did find some military
'D' Band
	dual tunable cavities that are for 400-450 and 450-500.  Gary
said that
	type device would work if they cover the 220 band, but I know
these I
	have aren't going to work at 222.  Does anyone on the
Fourlanders list
	have something suitable?  I'll try here first and if we don't
come up
	with something, I'll try the SVHFS list next.
	
	Thanks for checking.  Let me or Gary know what you have to help
the
	situation.  We'd like to the the 222 beacon back on the air.
	
	73, Bob
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