AM/FM Receiver Antenna Dilemma

Status
Not open for further replies.

haleve

Completely Banned for the Greater Good
Banned
Joined
Dec 21, 2011
Messages
380
Location
Pompano FL & Melville NY
I just purchased a Sherwood RX-4109 AM/FM stereo receiver for dx chasing so after connecting the unit to a 102" whip fed by LMR-200 coax with a PL259 connector & spade lugs for AM & a j-pole tuned to 155 MHz fed by RG-8X with a PL259 connectors & a SO239/Push on F connector for FM, result worse reception than the stock AM external/indoor coil & the stock FM 48" wire, any idea what I did wrong? The antennas were bolted & grounded to the balcony of my apartment. Anybody know of any outdoor AM & FM antennas that would work for my situation? whatever I use cannot extent beyond the balcony railing, Thanks in advance.
 
Last edited:

ka3jjz

Wiki Admin Emeritus
Joined
Jul 22, 2002
Messages
23,704
Location
Bowie, Md.
You've got a number of problems here.

Let's take the J pole first. If it's cut to 155 Mhz, it's entirely too short to be efficient at the 88-108 Mhz FM range. Too, a J pole has a relatively narrow bandwidth in which it's efficient -- sure it will receive something, but the further you go from its specification, the worse the performance. I don't know how you've got it connected to the stereo, but hopefully it's to the lugs as shown on page 5 of the manual.

The CB whip is another matter. As I mentioned in another thread, while it will receive something, it's entirely too short to be an effective receive antenna for the AM broadcast band. Too, connecting it to the other set of lugs will likely not work well either - I'm going to bet here, not seeing a technical schematic, that it's expecting a small loop (which exhibits a very high impedance) connecting across BOTH lugs, not just one of them. And, of course, the push on connectors can always be something of an issue.

To put it in simpler terms, the choice of antennas here is extremely poor. As I mentioned in another thread, you're far better off with a good sized loop that can be rotated - or one of the other commercially manufactured AM antennas as found in our Loops wiki. There are LOTS of plans for building loops on the web - our wiki only has a few of them..

On FM, you should join up with the WTFDA forums that another poster gave - they may well have some better answers for apartment folks.

best regards..Mike
 

gewecke

Completely Banned for the Greater Good
Banned
Joined
Jan 29, 2006
Messages
7,473
Location
Illinois
Try a FM dipole from radio shack for $7.99 and you're done.
Simple works well.


73,
n9zas
 
Status
Not open for further replies.
Top