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Title: Receiver Hybrid Post by: flintstone mop on November 15, 2005, 07:19:38 PM Hello Dear Friends,
There is a very nice article in this month ER for folks who would like to have multiple receivers on one antenna. The CATV splitter I'm using seems to be FB. Not sure of the isolation between receivers, though. Fred Title: Re: Receiver Hybrid Post by: WA1GFZ on November 15, 2005, 08:43:02 PM Load the ant port 50 or 75 ohms.
feed the antenna in one RX port and monitor another. Compare the S meter readings between this and the normal connection. A step attenuator will give you an exact. Title: Re: Receiver Hybrid Post by: W3NP on November 16, 2005, 08:47:33 AM Hello Dear Friends, There is a very nice article in this month ER for folks who would like to have multiple receivers on one antenna. The CATV splitter I'm using seems to be FB. Not sure of the isolation between receivers, though. Fred Is this an active splitter or just one of the little passive blocks? Title: Re: Receiver Hybrid Post by: flintstone mop on November 17, 2005, 10:30:38 AM Hi Dave,
It's a toroid coil and a couple of 18 ohm resistors. I think it was 7 turns on the primary and a bifilar winding of 5 turns for the secondary. The author claiming 30dB isolation and he was using Fair Rite cores #43 for the LF,MF,HF to 14mhz. Fred Title: Re: Receiver Hybrid Post by: WA1GFZ on November 17, 2005, 11:40:29 AM Fred,
I built one from the handbook and measured 26 dB port to port so 30 dB isn't out of the question. My unit is just a bifilar wound on a torroid and 1 resistor or two. Title: Re: Receiver Hybrid Post by: flintstone mop on August 28, 2006, 02:08:44 PM Hello AMers
I just wanted to activate this thread again to report that not all CATV splitters are created equal. I thought my present splitter was negligable(?) loss BUT come to find out below 7 mhz the loss was greater! 160M and 75M the loss is 7 dB and I tried another splitter and it was close to 10dB. So, I'm looking into brewing my own or buying a passive splitter from some Ham in LA. in W5 land. GOOGLE search receiver splitter. The Receiver is my trusty R390A and it checks out ok on all freqs AFTER the splitter. It's a little deaf on 40M, though. Must a tuned circuit in the RF deck with a crappy mica cap. The sensitivity is about 3 microvolts compared to 1 microvolt on the other bands. The purpose for thje splitter is to feed the Kenwood station and provide a "Main Antenna" input to the MFJ noise canceller. I don't want to have to remember to switch antennas for different needs while operating. Thanks for any replies. Fred Title: Re: Receiver Hybrid Post by: WA1GFZ on August 28, 2006, 03:48:00 PM Fred, AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Check the handbook for combiner for receiver dynamic range testing. Flip it around to become a splitter. No brainer to wind one up. Mini circuits also sells them. I bought a few at Hostraders last Spring for a couple bucks. Also called a return loss bridge if i remember. A 1/2 inch core and two resistors and a little wire. A 1:2 splitter from the handbook should do 4 to 6 DB loss. |