Home |
Search |
Today's Posts |
#5
![]() |
|||
|
|||
![]() Telamon wrote: Remember to terminate all ports at all times or your results will vary. The transformer type of splitter will have a "U" shaped response curve so you need to be within that band for it to work right. The resistive type is good from DC to some max frequency and you need to be in that range. From the transmitter value each output port should be 3 dB down when the other output port is terminated in 50 ohms. The actual loss will be a little larger then 3 dB by the splitters insertion loss. Oh yeah, and your meter is probably a through type instead of a load type so you need to put a 50 ohm load on the far side of the meter. When you check each splitter also switch the meter and its load in each leg to see how balanced the splitter is in each output port. Be sure to turn the transmitter off before all connections are made or you could damage your transmitter. -- Telamon Ventura, California I made some measurements last night. I decided to move from ~7MHz to 146 because 7MHz is just too close to the lower limit on my mMc splitter. I have an IC28A that is adjusted to give 1wt in low power. I used a 10dB Narda 766-10 power attenuator in series with the splitter input. I used another 766-10 attenuator in series with the output and the sensor head on Boonton RF power meter. I used a .5% 50 ohm terminator for the other port The resitive splitter gave me 6dB of POWER loss. The MC transformer based splitter gave me just over 3.2dB of loss. I called a freshly frocked dual PHD, EE and physics, I know and asked her what the heck is happening. The quick answer is the resistive splitter is like any other resitive voltage divider. The transformer unit is like a transformer step down, or step up. The only losses in a transformer splitter are the wire losses and the core loss. The R in the MiniCircuits dispates no power if all ports are matched. She invited me to "her" lab Friday afternoon and she will use the modern equipment to verify my measurements. She suggested that I treat the resistive network and use kichoff's (?spelling?, it has been too long since college) law to show the dissapation of each element. It is too late tonight and my head hurts from this stuff. Oh, and cctual S-meter measurements show the MC splitter has half the loss of the resitive splitter. On a good note, I picked up a 3 section "dB Products" heavy aluminium mast and another MC splitter like mine and a 1 in 8 out RCA active LF/HF splitter rated for use from 100Kc to 40Mc. It used Nuvisters and appears to have selectable MB/BCB filters. No manual, and the only diagram is stincyled on the inside of the lid. And no model number only an old "Signal Corp" decal. My friend retired ATT microwave engineer and is moving to AZ because he is sick of the winter snow here. He has a storage building full of such junk and I get to cherry pick it and haul it to another friend. I hope to check the RCA coupler before going to the university lab. It would be nice to run a SN and frequency response. Terry |
Thread Tools | Search this Thread |
Display Modes | |
|
|