From W8EK at speakeasy.net  Sat Dec 20 10:46:47 2008
From: W8EK at speakeasy.net (Ken Simpson, W8EK)
Date: Sat Dec 20 10:54:01 2008
Subject: [TVI-RFI-EMI] Low Pass TVI Filters FS
Message-ID: <494D1367.7030907@speakeasy.net>


Low Pass TVI Filters For Sale:

A low pass TVI filter is added to the transmitter (inserted
in the coax line after the transmitter or transceiver) to
reduce harmonic interference.

Nye Viking Low Pass Filter Model 020-001
This filter is rated at 2000 watts, with over 65 db of
attenuation above 57 MHz. These are about $60 new;
this one is close to new for only $35.

Johnson 250-20 Low Pass Filter
This is a 52 ohm cylindrical low pass filter with a cut
off frequency of 45 MHz and 75 db of attenuation.
It is rated to take 1000 Watts of AM, or 5000 Watts
PEP SSB. It has SO-239 connectors on each end. $30

Drake TV-3300-LP Low Pass Filter
This is a modern low pass filter to go between your transmitter
and antenna, and has been optimized to have more attenuation
in the 40 MHz region, where many TVs have their IF. It is good
for 1000 Watts "average" according to the manual, and has
over 80 db attenuation at 41 MHz. This one looks great, and
includes the paper work. $30

Drake TV-1000 Low Pass TVI filter
This is the low pass TVI filter that is in the copper case,
and may also be used on the low end of six meters, as well
as HF.
It is a 50 ohm filter and is good for 1000 W below 30 MHz,
and about 200 W up to 52 MHz.
This one works fine and looks good also.
With paper work for $30.

B & W model 426 low pass filter
B & W TVI filter, cuts off just above 10 meters,
and will handle 1500 Watts. SO-239 connector on each end.
This is an older model that seems much heavier duty. It weighs
almost twice as much as the newer models, and looks like it
would take more power. It likely was made in the days that
plate modulated AM was the rule. $28

B & W FL-10/1500 (Formerly known as model 425) low pass filter
B & W TVI filter, 50 ohm. It cuts off just above 10 meters,
and will handle 1500 Watts. SO-239 connector on each
end. This is the latest model B & W filter. It is in very nice
condition; it looks very close to new. With paper work $40.

Prices do not include shipping from Florida.

Thanks.

73,

Ken, W8EK

Ken Simpson
E-mail to W8EK@speakeasy.net or W8EK@arrl.net
Voice Phone (352) 732-8400






From roncasa at verizon.net  Sat Dec 20 11:37:51 2008
From: roncasa at verizon.net (ron)
Date: Sat Dec 20 11:45:00 2008
Subject: [TVI-RFI-EMI] Re: Low Pass TVI Filters
In-Reply-To: <494D1367.7030907@speakeasy.net>
References: <494D1367.7030907@speakeasy.net>
Message-ID: <494D1F5F.5070301@verizon.net>

Ken Simpson, W8EK wrote:
>
> Low Pass TVI Filters For Sale:
 
I wonder, with the analog stations shutting down and moving to UHF for 
digital conversion, will any of this be needed.

Ron
wb1hga
"how many of you believe in psycho-kinesics? Raise my hand."
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.qth.net/pipermail/tvi-rfi-emi/attachments/20081220/d1fc85a9/attachment.htm
From larry.d.lefczik at lmco.com  Wed Dec 24 09:10:13 2008
From: larry.d.lefczik at lmco.com (Lefczik, Larry D)
Date: Wed Dec 24 09:17:59 2008
Subject: [TVI-RFI-EMI] Re: Low Pass TVI Filters
In-Reply-To: <494D1F5F.5070301@verizon.net>
References: <494D1367.7030907@speakeasy.net> <494D1F5F.5070301@verizon.net>
Message-ID: <F2AFF55F2400AF4E8EA89388A1346CC91BFBF5C2@emss04m20.us.lmco.com>

Actually some of the DTV stations will migrate back to VHF after 2/18.
UHF was just a second channel to simulcast DTV until transition is
complete.

 

It will be a real challenge now to diagnose TVI since DTV has different
reactions to interference.  A doubt we can look at the screen and figure
out what type of interference is causing pixilation or complete video
loss.

 

The saving grace is that many viewers are going to cable/FIOS because it
is easier than trying to figure the OTA DTV stuff out.

 

________________________________

From: tvi-rfi-emi-bounces@mailman.qth.net
[mailto:tvi-rfi-emi-bounces@mailman.qth.net] On Behalf Of ron
Sent: Saturday, December 20, 2008 11:38 AM
Cc: TVI - RFI List
Subject: [TVI-RFI-EMI] Re: Low Pass TVI Filters

 

Ken Simpson, W8EK wrote: 


Low Pass TVI Filters For Sale: 

 
I wonder, with the analog stations shutting down and moving to UHF for
digital conversion, will any of this be needed.

Ron
wb1hga
"how many of you believe in psycho-kinesics? Raise my hand."

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.qth.net/pipermail/tvi-rfi-emi/attachments/20081224/52cf21e6/attachment.htm
From danki6x at earthlink.net  Wed Dec 24 13:33:27 2008
From: danki6x at earthlink.net (Dan Violette)
Date: Wed Dec 24 13:40:58 2008
Subject: [TVI-RFI-EMI] Re: Low Pass TVI Filters
In-Reply-To: <F2AFF55F2400AF4E8EA89388A1346CC91BFBF5C2@emss04m20.us.lmco.com>
Message-ID: <3ADEE95C8FF5496DA0548891385FA1CE@danpent4>

Yes, channels 7-13 will still be occupied.  This is a great help since the
low-VHF are the most likely to be hit with RFI.  Dan, KI6X

  _____  

From: tvi-rfi-emi-bounces@mailman.qth.net
[mailto:tvi-rfi-emi-bounces@mailman.qth.net] On Behalf Of Lefczik, Larry D
Sent: Wednesday, December 24, 2008 6:10 AM
To: TVI - RFI List
Subject: RE: [TVI-RFI-EMI] Re: Low Pass TVI Filters



Actually some of the DTV stations will migrate back to VHF after 2/18.  UHF
was just a second channel to simulcast DTV until transition is complete.

 

It will be a real challenge now to diagnose TVI since DTV has different
reactions to interference.  A doubt we can look at the screen and figure out
what type of interference is causing pixilation or complete video loss.

 

The saving grace is that many viewers are going to cable/FIOS because it is
easier than trying to figure the OTA DTV stuff out.

 

  _____  

From: tvi-rfi-emi-bounces@mailman.qth.net
[mailto:tvi-rfi-emi-bounces@mailman.qth.net] On Behalf Of ron
Sent: Saturday, December 20, 2008 11:38 AM
Cc: TVI - RFI List
Subject: [TVI-RFI-EMI] Re: Low Pass TVI Filters

 

Ken Simpson, W8EK wrote: 


Low Pass TVI Filters For Sale: 


I wonder, with the analog stations shutting down and moving to UHF for
digital conversion, will any of this be needed.

Ron
wb1hga
"how many of you believe in psycho-kinesics? Raise my hand."

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.qth.net/pipermail/tvi-rfi-emi/attachments/20081224/7140024f/attachment.htm
From ingraham.ma.ultranet at rcn.com  Fri Dec 26 10:14:44 2008
From: ingraham.ma.ultranet at rcn.com (Andy)
Date: Fri Dec 26 10:22:14 2008
Subject: [TVI-RFI-EMI] Re: Low Pass TVI Filters
References: <3ADEE95C8FF5496DA0548891385FA1CE@danpent4>
Message-ID: <056d01c9676c$af152fe0$0302a8c0@Ingraham>

Even 2-6 (low-band VHF) is still used in a limited number of places.
(Either that, or the table of post-transition channels is incorrect.  It
shows a few stations staying on the lower channels; and I've read elsewhere
others saying that this is indeed true.)

If the RFI is small enough, hopefully the DTV will reject/overcome it.
Digital being typically all-or-nothing, when there is sufficient RFI to
impinge on the TV reception, it will quickly just go away rather than
becoming snowy or distorted.  Will be interesting to see what happens.

Andy

