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Author Topic: Triplexers and filters  (Read 316 times)

NO9E

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Triplexers and filters
« on: May 20, 2022, 01:10:41 PM »

I consider triplexer for my tribander to enable SO2R. Do I need high power filters after the duplexer? I already have a 6 band low-power bandpass filter.

If one does SO2R with a tribander, how useful is it considering that favorite directions on two adjacent bands may be different.

Ignacy NO9E
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K5LXP

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Re: Triplexers and filters
« Reply #1 on: May 20, 2022, 01:20:26 PM »

I would guess that would depend on the port to port isolation of the triplexer, transmit noise and receiver rejection of your transceivers.  One that I see on the DXE site shows 35dB isolation, which is not enough. 

Mark K5LXP
Albuquerque, NM
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NO9E

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Re: Triplexers and filters
« Reply #2 on: May 20, 2022, 02:41:44 PM »

High power filters have an attenuation of around 60 db. ICE type low power filters have official attenuation of about 50 db
- I measured 40 db plus--  although they do not attenuate harmonics generated by the amplifier.

Ignacy NO9E
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K3TN

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Re: Triplexers and filters
« Reply #3 on: May 21, 2022, 04:35:17 AM »

On your second question, since you are one the east coast you will want to be pointing to EU a lot during contests and in the mornings 10/15/20 can all be wide open to EU.

Afternoons are different - Asian and Caribbean openings and EU opening in different directions is one of the reasons why the big stations have multiple antennas/towers.

73 John K3TN
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John K3TN

W1VT

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Re: Triplexers and filters
« Reply #4 on: May 21, 2022, 05:20:07 AM »

The Asian openings from New England are low angle which often requires a high tower.  Caribbean openings have much higher angles.  Instead of using the same antenna, a side mounted antenna lower on the tower aimed at the Caribbean is a better solution.
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NO9E

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Re: Triplexers and filters
« Reply #5 on: May 21, 2022, 09:18:38 AM »

I have rotatable Jk Mid Tri 40 at 100 ft and rotatable JK Mid Tri at 60 ft. Also Spiderbeam at 40 ft. Having the stacked beams at different directions would require double triplexers with associated filters, double stack match plus a larger SO2R  switch.   

The Spiderbeam works well to the Caribbean  but less so to SA.

Looking at options. Triplexers, or extra tower(s) with fixed antennas to SA and perhaps OC. One 20-10 triplexer is about $500 alone and almost $2k with band pass filters. I already have low power bandpass filters.

Ignacy NO9E

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N1UR

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Re: Triplexers and filters
« Reply #6 on: May 22, 2022, 03:44:45 AM »

The cheapest effective SO2R would be a duo-band 10/15 at 80ft - fixed to EU.  With the higher SFI, that would give you a lot of flexibility including running EU late on 15 while exploring the N, W, S later in the day on 20 or 10.

You would trade some pattern distortion on 10/15 on your stack.  However, its not clear to me that would be fatal.  Would need to be modelled. 

Ed  N1UR
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K6JH

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Re: Triplexers and filters
« Reply #7 on: May 30, 2022, 03:30:09 PM »

One of the latest Hamvention “Contest University” talks mentioned that multiple tribanders interact and screw up patterns. F/B, gain, etc.

Hence the reason big contesters go monobanders and multiple towers. Little pistols make compromises.
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Jim K6JH

WB2VVV

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Re: Triplexers and filters
« Reply #8 on: July 25, 2022, 07:55:54 PM »

I consider triplexer for my tribander to enable SO2R. Do I need high power filters after the duplexer? I already have a 6 band low-power bandpass filter.

If one does SO2R with a tribander, how useful is it considering that favorite directions on two adjacent bands may be different.

Ignacy NO9E

Yes, the currently available tri-band tri-plexers only have around 12 to 15 dB of port to port isolation, which is not nearly enough to protect one rig's receiver from the other rig's transmitter. That is why you need to cascade individual bandpass filters with the three ports on the triplexer. This will raise the port to port isolation by another 30 to 50 dB depending upon the specific filters, which is usually sufficient as it works both ways. Bear in mind that that the 20m harmonic will still be quite loud on 10m if the two VFOs happen to line up exactly on the 2X multiple, but the filter isolation will avoid blocking, compression and de-sense. The power rating of these filters depends upon the power level you use with your transmitter.

Possibly I am wrong about the configuration of your current 6-band filter but I am guessing it is only working on one rig at a time and not both rigs at the same time - as the triplexer cascaded with 3 individual bandpass filters would.
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NO9E

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Re: Triplexers and filters
« Reply #9 on: July 26, 2022, 01:06:46 PM »

For SO2R, I purchased 2 low power bandfilters, one for each slice of Flex 6600. Also VA7AM triplexer (30db port isolation) and a high power 40m bandpass filter (to eliminate 20m harmonic) are coming this week. I ordered PG XL amp and antenna Genius 8x2 switch, both advertised as available on the Flex site. PG XL came but the Antenna Genius is currently unobtainum. So no SO2R tests anytime soon. 

Ignacy NO9E
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KC0W

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Re: Triplexers and filters
« Reply #10 on: July 26, 2022, 03:52:06 PM »


I ordered PG XL amp and antenna Genius 8x2 switch, both advertised as available on the Flex site.

 Wow........I don't believe it!!!

 


                                         Tom KH0/KC0W
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NO9E

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Re: Triplexers and filters
« Reply #11 on: August 22, 2022, 04:28:47 AM »

I got all of it tested. Flex 6600, PG XL SO2R amp, TG XL SO2R tuner, 8x2 4o3a switch. All components communicate via Ethernet so no PTT cables. Switching works well with N1MM+. Filtered by two low power bandpass filters + 40m VA6AM filter.

Testing revealed that the filters work but other problems emerged: internal isolation between bands in Flex 6600 and retransmission. Take transmit on 40m and receive on 20m. First, there is a S9+ 1 KHz wide second harmonic on 20 due to internal leakage in Flex 6600. It is narrow enough not to bother. Second, there is a 40KHz wide raspy signal around the first one due to retransmission from electr(on)ics around the house.  I have heard that the source of the retransmission may be impossible to find. I was lucky to find that the raspy signal disappeared when either the lights in one area are switched on, or when the fuse to those lights is switched off.

So the triplexer and the band pass filters are fine. The biggest problem may be to find source of retransmissions, and they may be different on different bands.

Ignacy, NO9E
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