Thanks for a very informative video. I bought a TRPD 1554 on ebay that was tuned to 158 mhz and 155 on the low side. I had to install 18ph capacitors on the high side to get back the 600 khz split for ham use (as Telewave recommended). However, the notch on both the TX and RX sides was on the higher side. Since I am not in the US, to send the duplexer back to Telewave, I ordered some RG402 cable and made my own coupling loops and was successful getting the notches where I wanted on both sides. When the duplexer was tuned using the Rigol 815TG, I was able to achieve over -75 db at about 1.2db insertion loss per side. However, knowing that reducing insertion loss too much lowers the Q, I chose to settle for 1.5db insertion loss that gave me better Q. Although the final effort seems satisfactory, I am assuming that my inter cavity cables might be cut for higher than the ham band. Can you please tell us the theory behind how to move notches from the low side to the high side and vice versa? Is it dependant on inductance if the loop? At least one other person has asked the same question and an answer will be beneficial to us hobbyists. Thanks Telewave.
Hello, I'm making some duplexers (first time) I want to know if the TX and RX duplexers are the same, I mean they have both in TX and RX side an capacitor? because the RX side is opposite of the TX, how to get that reverse?
Hi Sergio, Think of the duplexer as a Pass High side and a Pass Low side. There is no limitation between TX and RX Side, but rather, a Pass High Frequency side vs Pass Low Frequency side. Connect the TX and RX to match the frequency specified side of the duplexer.
Reading my post above might help if you have bought a used duplexer that was tuned for a higher frequency outside the ham bands. Maybe not, but just a thought
Thanks for a very informative video.
I bought a TRPD 1554 on ebay that was tuned to 158 mhz and 155 on the low side. I had to install 18ph capacitors on the high side to get back
the 600 khz split for ham use (as Telewave recommended). However, the notch on both the TX and RX sides was on the higher side. Since I am
not in the US, to send the duplexer back to Telewave, I ordered some RG402 cable and made my own coupling loops and was successful getting the notches where I wanted on both sides.
When the duplexer was tuned using the Rigol 815TG, I was able to achieve over -75 db at about 1.2db insertion loss per side. However, knowing that reducing insertion loss too much lowers the Q, I chose to settle for 1.5db insertion loss that gave me better Q. Although the final effort seems satisfactory, I am assuming that my inter cavity cables might be cut for higher than the ham band.
Can you please tell us the theory behind how to move notches from the low side to the high side and vice versa? Is it dependant on inductance if the loop? At least one other person has asked the same question and an answer will be beneficial to us hobbyists. Thanks Telewave.
Thanks for a very much this video. for help me.
Great video guys. You make fantastic products.
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I have a combiner with 4 of these cavities in the 88 - 108 MHz band that I need to retune. How do I calculate the length of the cables?
Measure the length of conductor and length of tuning couple
What is the valu or specification of Piston tuning capacitor in TPRD-1454 ? It wikk be the great help
20pf in the TRPD1554
Hello, I'm making some duplexers (first time) I want to know if the TX and RX duplexers are the same, I mean they have both in TX and RX side an capacitor? because the RX side is opposite of the TX, how to get that reverse?
Hi Sergio,
Think of the duplexer as a Pass High side and a Pass Low side.
There is no limitation between TX and RX Side, but rather, a Pass High Frequency side vs Pass Low Frequency side. Connect the TX and RX to match the frequency specified side of the duplexer.
@@telewave-io9709 What is value and part no of Tunning capacitor for TPRD 1454
Reading my post above might help if you have bought a used duplexer that was tuned for a higher frequency outside the ham bands. Maybe not, but just a thought
This video didn't show how to tune the cavities...the 1505 isnt the same as these cans.
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