Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: AM antennas
Posted: Wed Aug 24, 2005 11:12 am
Joined: Sat Apr 23, 2005 2:09 pm
Location: Tampa, FL
Anyone know of any improvements regarding AM antennas? I've been doing some reading and found some interesting articles regarding the DLM (URI Robert Vincent) and EH (Ted Hart) antennas.
I'm curious if there are others out there. I'm especially interested in smaller AM broadcast antennas that are "close" to commercialization.... if there are any.
Post subject: am MW antennas
Posted: Wed Sep 14, 2005 12:53 pm
Nothing beats a good resonated loop for MW BCB DX. The higher Q loops even help selectivity in addition to being directional- if ur listening to AM broadcast, diretionality is important, due to co-chanel reuse with georaphic diversity [the FCC broadcast model]. Also a loop will allow U to point it to the ionosphere for listening at to skywave night for distant stations while rejecting the groundwave of the local station. The hardest thing to get is the tuning capacitor-- a real air varible is the best-- varicaps just dont have the dynamic range for over the air broadcast without esoteric circuits and a lot of care. Look at kiwa.com for a good small MW loop-- this is my friend Craig- a good guy who sells honest products-- small shop. He used to make a huge loop, but discontinued it. One other thing-- make the preamp and capcitor fully differantial and balanced to ground for best null rejection. Unbalancing a loop ruins it-- I know where to get dual air varibles too--this post could go on for days-- so i will stop for now.