MFJ Duplexer--Two radios, one antenna, or vice versa (

[@graywolf1911]

It is such a great service to all of us to review various pieces of Ham equipment. Thank you so much Dave !!

[@submarineradioman5535]

Thanks Dave - my ENTIRE uhf/vhf antenna farm is located in my attic! Wide band Discone, 6 meter halo, 144/432 And 220 J poles. At present I have 1/2” hardline feeding them. They’re used strictly for local comms so this unit should help eliminate unnecessary milspec feeds and replace them with coax.

[@parkerd619]

Thank you for the information in this video. I purchased the MFJ 916b to use on my UHF and VHF radios.

[@USXPOP]

Neat little review. diplexers and duplexers have been around a long time. Keep them coming.

[@forgetyourlife]

yeah and they are both totally different.

[@blitzdough]

This is exactly what I needed to know. Thank you!!

[@kg4hlz]

"I commend MFJ for it's build quality" That's something that you don't hear every day.

[@K6TJO]

FYI: October 2019 Pg. 41 of QST Magazine has article about Duplexers and Diplexers. I am no expert but I beleive what you are describing is a Diplexer rather than a Duplexer.

[@Barracuda48082]

Dave..you have no idea how I have been thinking how to do my dual bander utilizing my celwave 70cm 8db gain glass vertical and my 2m 6db j pole together..!! This diplexer will save the day. Ten more feet up, add the celwave vertical with more lmr 400, another arrester and Im in the groove again.. Thanks so much for the tip..my gears were spinning. 73, Kb8qlz

[@timbacchus]

It sure saves the SO239 that is on the radio from constant screwing on and off.

[@gregtramell258]

Good info. I would like to see a video for a digital watt meter/SWR meter

[@jlwilsonjr]

I have only been a Technician for about 6 months and am taking the General test in 2 weeks. I have an Icom 7300 and a Yaesu FT 991A. Outside I have a Diamond Antenna X50A and a Par EdnFedz EF-Allbandkw. Is there an adaptor like the one in this video that will work on the HF antenna? Just so you know, I cannot thank you enough for all the video's that you have. I really appreciate you sharing your knowledge with everyone.

[@mrtonicsvls3624]

Can I use another duplexer down where the radios are and connect one cable to the HF radio and one to the UHF radio?

[@titaniummaster1532]

What about one radio sharing two antennas . One antenna for 136-174 and one for 400-470? Diplexer? I see mostly duplexers are they different ? I’m getting mixed information. Weather proof is a plus. Thank you for any help 😊

[@gary6212]

Is there any way/device that would let me share a dual-band antenna with between two devices without splitting out the bands? What I would like to do is have 1 dual-band antenna feeding a normal dual-band (UHF/VHF) transceiver and also feeding an SDR - is that possible or do I really need two different dual-band antennas?

[@mrjg1013]

Is it best to have a dedicated antenna for frequency you want to use? Like when using the icom ic-9700, which has three inputs each for the 2m, 70cm, and the 23cm, one antenna each. Or is there no differences at all or losses using a single three band antenna with some kind of tri-plex connector. I was always under the impression when using splitters etc. you have dbs loss or something?

[@pfmcdermott1]

I’m currently wondering the same thing. Also, losses from the triplexer aside I’m wondering what downside there is, if any, to a single multi omnidirectional antenna for the 9700 v three separate omnidirectional antennas. There’s limited space/safe attachment points on my roof for antennas to be mounted and have some distance apart so it’s getting crowded with a desire for vertical for FM use 10,6,2,1.25M and 70 and 23cm antenna needs.

[@TE5LA-GAMING]

I have a multiband discone home antenna for ham transceiver. Is there way with any product similar to this to also use the antenna on a police-type scanner? I mean without using a manual switch.

[@matth5309]

Can two of these be used back to back i.e. both common ports connected together? I have two antennas in my attic that I want to connect to two radios in the shack using one coax.

[@kg7jev671]

Will this work to connect a dual band transceiver and a digital scanner through 1 antenna?

[@glennpersons541]

MFJ-916B is not a duplexer, it is a diplexer. A duplexer is used on a repeater. Most companies mislabel them; who knows why they can’t get it right.

[@kennethherring2918]

You would think that these manufacturers like MFJ would label it correctly.

[@twohandsandaradio]

Hense why I buy nothing from MFJ.

[@weldorguy]

Can you use an antenna cable splitter connection to use one antenna for a Duplexer set up? I want a mobile unit for a SHTF vehicle and it would be tx 100w on one side and rx 10w on the other side....and the antenna would be 150w sg-7900

[@darylmorning]

I'm betting it's because the uninformed look for a DUplexer instead of a DIplexer and they label it to match the belief as opposed to the reality.

[@RegiePinoy]

Nice video and thanks for sharing this. One question I have tho is with the scenario of one radio and two antennas... Those antennas has each own swr readings. What happens to them after joining them together? Getting higher swr's?

[@90Christopher]

Haw far dos the antennas have to be apart? Wen you but it on a Uniden bcd325p2 police scanner. Can you use any split?

[@Whiskey6Radio]

Would this work if I connected a scanner to my comet gp6 while running my Yaesu 2980 at the same time?

[@alexgottmituns7049]

Suppose I have a 900Mhz radio and I have two antennas for it (a 3db and a 10db, both omnis). Will this work? (the radio is on top of a hill )

[@johnbesedic9432]

What would happen if you key up both radios at the same time. I have a UHF DMR repeater and want to use the same antenna for my System Fusion VHF repeater. I'm scared what will happen if both repeaters keyup at the same time.

[@bentobias6396]

Hi Dave. Love your videos! I need to hook two dual band mobile radios to a single dual band antenna. Although the radios are dual band, they may be operating in the same band, at up to 50watts. Can you advise which device I should use to do safely? Would it be a duplexer or diplexer? Thanks!

[@alfredorodrigues2318]

hi so if go from 1 mz to 200 mhz can be used in 40 meter band ??

[@JayN4GO]

Used as a high low pass filter. Doesn’t do well at all on 220. Could use tighter tuning on 430mhz. Variable caps would’ve made it better.

[@JimN5QL]

Mast mounted unit = +$20 Non sealed unit = -$20 +$20 of more coax.

[@dinohahanusa8483]

how to use automatix coaxial switch AS-2 on vhf radio

[@1967mikerod]

What do you use if you want to have two of the same radios on the same antenna that are in different parts of the house? to be used at different times? one in the den the other in garage never at the same time

[@frankstapanowich6687]

Shakespeare makes a automatic switch that you can use with 2 radios and one antenna. When you PTT to transmit it switches to that radio and stays there till you key the other radio.

[@ki6ada2005]

I want to mount this duplexes on the wall. Do you have any mounting ideas?

[@richarde735]

🙄

[@airborne63]

Velcro?

[@anthonygallo3576]

Seriously, how did u ever pass a ham test

[@lyfandeth]

How many db loss in that box, and the extra connection?

[@ZAR66]

Its negligible.

[@James_Bowie]

MFJ claims 0.2dB insertion loss, however a reviewer on eHam says: "On 2 meters the unit is excellent with 0.2 dB insertion loss across the band. Also on 70 cm the unit is Very good with roughly 0.3 dB insertion loss across the band. HOWEVER if you are planning to use it on 220 this unit is not the one to use. At 219 MHz insertion loss is 4 dB At 220 MHz insertion loss is 5 dB At 222 MHz insertion loss is 6 dB At 225 MHz insertion loss is 8.5 dB " So, would be interesting to see someone verify those figures.

[@seltenfotog3115]

Question: Can I use a 5 watt GRMS radio set on channel1 (for instance) and a second 5w GMRS radio set on channel 15 using this device. My thought is this combination could allow a make shift type of repeater using one antenna? (using speaker jack (radio 1) plugged into microphone jack on radio 2 (Vox turned up to high sensitivity)

[@Siskiyous6]

Is it possible to use two antennas to two radios on a single line without duplexers. On my Jeep I would love to run a GMRS antenna and a 10 Meter Antenna through just one bulkhead connector through my solid roof.