TV Fool  

Go Back   TV Fool > Over The Air Services > Special Topics > Antennas

Notices

Reply
 
Thread Tools
Old 9-Dec-2014, 12:43 AM   #1
dbseeker
Member
 
Join Date: Apr 2014
Posts: 36
FM trap and 7-51 antennas

Is there any need for an FM trap preamp on a channel 7-51 specific antenna?
To be more specific, I have a fringe reception issue on real channel 7 with an antennacraft Y71013 coupled with a RCA RVPRAM IR with the trap set on of course. I have an FM station .7 miles away 89.1 with a strength of +4dbm.
Would like to try a lower noise preamp Kiztech and/or CPA 19 both of which I have and both have no FM trap and use a USVJ to couple. At 62, I don't want to get on the roof anymore if there is no reasonable chance for success.
dbseeker is offline   Reply With Quote
Old 9-Dec-2014, 1:07 AM   #2
ADTech
Antennas Direct Tech Supp
 
Join Date: Jan 2010
Posts: 2,942
What is unknown is the sensitivity of your antenna to FM signals.

What is known about your pre-amp is that 1) it's internal FM filter isn't particularly effective at that low of FM frequency and 2) that it's plastic case permits substantial signal ingress, in spite of having a metal plate that helps somewhat.

Bottom line is that there really isn't much of a downside in using one or two FM filters at the input the the preamp to kill off FM from entering it via the antenna's reception path. Better yet, swap out to a CPA19 since you have one and use the FM filters. That amp was exceedingly difficult to overload.
__________________
Antennas Direct Tech Support

For support and recommendations regarding our products, please contact us directly at https://www.antennasdirect.com/customer-service.html

Sorry, I'm not a mod and cannot assist with your site registration.
ADTech is offline   Reply With Quote
Old 9-Dec-2014, 2:41 AM   #3
dbseeker
Member
 
Join Date: Apr 2014
Posts: 36
Each FM filter has it's own noise figure. Can you recommend a low noise figure product for the FM filter that would help me in this marginal fringe reception situation ?
dbseeker is offline   Reply With Quote
Old 9-Dec-2014, 2:50 AM   #4
dbseeker
Member
 
Join Date: Apr 2014
Posts: 36
Would the HLSJ be of any efficacy?
dbseeker is offline   Reply With Quote
Old 9-Dec-2014, 12:30 PM   #5
ADTech
Antennas Direct Tech Supp
 
Join Date: Jan 2010
Posts: 2,942
Any filter, whether an FM filter or an HLSJ, will have an attendant noise figure (insertion loss) in the spectrum that is of interest in it passing. It's unavoidable, but the best course is to limit it as much as possible.

Either a Pico-Macom or Holland HLSJ or our (Antennas Direct) FM Filter would be suggested to try out, I would not use the Radio Shack filter as it cuts in at a higher frequency and would affect 89.1 very little. If using the HLSJ, terminate the unused port.
__________________
Antennas Direct Tech Support

For support and recommendations regarding our products, please contact us directly at https://www.antennasdirect.com/customer-service.html

Sorry, I'm not a mod and cannot assist with your site registration.
ADTech is offline   Reply With Quote
Old 9-Dec-2014, 10:44 PM   #6
dbseeker
Member
 
Join Date: Apr 2014
Posts: 36
Thanks for your wonderful expertise!!
dbseeker is offline   Reply With Quote
Reply

Bookmarks

Go Back   TV Fool > Over The Air Services > Special Topics > Antennas



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off




All times are GMT. The time now is 4:22 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © TV Fool, LLC