Bandpass filter

AB7R · May 22

I want to insert a bandpass filter in the rx chain for 6M.

Do I use the RX INB and XVTRB for this? Then in the slice select XVTR B for TX and RXB for receive?

KD0RC · May 22

Which Flex rig do you have? Some of the older rigs, like the 6700 have a set of RX loop jacks so that you can insert a RX-only filter. The newer radios don't have this.

How much power can be transmitted through the filter? If it is rated for 100 W or more, then you can insert it between the ANT connector and the antenna. Just don't forget to remove it when operating other bands (could be very bad for the filter and the radio).

If it is a RX-only filter and you have a separate RX antenna, then put the filter between RXA and the receive only antenna.

If it is a RX-only filter, but you only have one antenna, then you can use an SDR TR switch so that the filter is out of the loop when transmitting. The SDR jack of the switch would go to the RXA jack of the radio. You would set the RX antenna to RXA in this case.

AB7R · May 22

Thanks Lee. I had a 6700 when they first came out. I remember being able to do this. I am surprised it is not available on the 8600. :(

I had an sdrswitch.com switch but thought it was no longer needed…so I sold it. I am a dumb as#!.

Tnx

Greg

Mike-VA3MW · May 22

Hi Greg

The 8600 has built in 7th order band pass filters. Are you sure you need more?

Mike

AB7R · May 22

Had 2 slices open. 1 on 6m one on 20m. Monitoring 6m while working ft8 on 20m. A few decodes showed up on 6m wsjtx instance.

CConsidering returning 8600 to get on 520 list.

Mike-VA3MW · May 22

It is possible that is a common mode current issue. Do you have any chokes on your feedline? And, what sort of antenna layout do you have?

I have an 8600 and I do not have the same problem which sort of leads me to believe it is outside the radio. I have Mix 43 chokes on all my feedlines, actually all cables going to the radio. You might want to give it a try.

It is possible that even after 70dB of attenuation, some of the 4th harmonic still might leak through. Hmm… 14.074*4 is 56.296Mhz, so that doesn't fit.

As a test, pull off the 6M antenna lead and see if you still have the same issue.

KD0RC · May 22

Hi Greg, when you are operating this way, do you see the "Wide" indicator on your screen? If you have a panadapter set too wide, or if you are on the same antenna port, your internal bandpass filters will be switched out.

Mike-VA3MW · May 23

And, Len has a great point! I forgot about that.

Bill AB7AA · May 23

Mike,

You use chokes on all leads, such as RF Coax, PTT control, network, power, etc.? Which beads do you recommend?

Bill AB7AA

Mike-VA3MW · May 23

https://palomar-engineers.com/rfi-kits/ham-radio-rfi-solutions/transmitter-rfi-kits

Bill AB7AA · May 23

Thanks Mike. Bill AB7AA

AB7R · May 24

I have the DXEngineering chokes on all my CAT8 cables for all devices. These chokes have pigtails the insert to the device and you plug the cable into the other end. Coax and power cables are wrapped 6-7 turns around the LARGE snap cores. Smaller ones on other lines. Jumpers also have split beads on them.

I think this is an antenna proximity issue. Small HOA yard….35ft carbon fiber mast holding the EFHW and a 3 el 6M yagi at about 12 ft. I recently installed a DXCommander rapide and the top is about 10ft from the EFHW wire. :(

Bandpass filter

Welcome!

Answers

Leave a Comment

Welcome!

Quick Links

Categories