As always, thanks for looking

After a several month wait and bugging Mark (the owner of iPortable) regularly, my EMCOMM box is scheduled to arrive tomorrow-I'm pretty stoked.

This weekend I will be making the pilgrimage to HRO for some SO-239 bulkhead connectors and other sundries, as well as a Comet antenna duplexer to run two radios off of one dual band antenna.

The duplexer I am considering is the Comet CF-4160J, more info HERE


The two radios I will be using are an Icom IC-7000 (HF/VHF/UHF), and an Icom F2821D (UHF). This particular duplexer has two inputs-one of them is labeled for 1.3 to 170MHz use, and the other is labeled for 350 to 540MHz. I intend to connect the VHF/UHF antenna connector on the 7000 to the first input (1.3-170MHz) and the UHF antenna connector on the F2821D to the second (350-540MHz). The HF antenna connector on the 7000 will have it's own separate antenna.

My question is this: If the IC-7000 VHF/UHF antenna connector is connected to the 1.3-170MHz connector, does that mean that I cannot use the UHF capability of the 7000 unless I swap the antenna jumper to the second, higher frequency connector? Put another way, will the band pass filter on the duplexer prevent UHF operation through the first connector, or does it merely exist to provide isolation between the ports?

Thank you in advance for your help. I hope I'm making sense I've asked two different people who have looked at me like I was insane, so my apology if I'm not articulating this clearly. Boiled down to simplest terms-can you run, for example, a 440MHz signal through a duplexer port that is labeled for 1.3-170MHz without harming the radio or hurting your signal?

ETA: Here's a pic of the ongoing project. The duplexer has been installed, and the box is UHF/VHF capable. Next up will be installing the SG-237 tuner for HF operation:

Did some initial testing with my tripod mounted Diamond X-50 antenna, and everything is working perfectly so far. The iPortable enclosure has been very easy to work with.

I am no expert, but I think what you are trying to do will only result in the magic smoke coming out of one of the rigs.

ETA: I do not think they were designed to run 2 different rigs, and if you were to transmit a UHF signal from the 7k, I am not sure how it would work.

The 7k has a diplexer built into the radio, I think you will be better off with 2 antenna's, and 3 outputs.
ETA2: You are correct, you would not be able to use the UHF side of the 7k. The diplexer will have a low pass, high pass setup. It is possible, but I think it is going to be unwise to do so. It would be much wiser to run 2 antenn'a, a dual band on the 7k and just a simple single band on the UHF radio. The attempt to run 2 rigs on one antenna at the same time is taking a big risk.

I'm not sure if I understand exactly but here is what I run.  Kenwood 830G commerical uhf radio and a Icom 2100 vhf radio going to a duplexer (more correctly called a diplexer) with the combined feed going to one dual band antenna.  So if you were intending to use the vhf section of the 7000 inputed into the vhf side of the diplexer and another uhf radio inputed into the uhf side and the output to a dual band antenna that should be fine.  That is what those devices are designed to do.  Go to Comets web site and you should find some diagrams showing the usage.  The diplexer comes with a chart showing the exact thing I am talking about.  If the 7000 has 6m then usually it would come out the HF output on the radio and you could use another diplexer to split the 6m away from the HF -  that's what I do on my 706mIIg.  I guess you want to listen to u and v at the same time.

I believe that's the same model duplexer I'm running in my vehicle, but for the opposite purpose (two antennas, one radio.)

The documentation was kinda weak in the translation department, but what I took away is that the setup you want will work as you described, to a T.  The low side will only allow the VHF signals out, and the UHF side will work as desired for that purpose as well.  I don't know if it would cause damage to the 7000 if you pushed out UHF on it through the VHF side, but I'd bet it wouldn't be pretty.

I'm sure there's a way to get two UHF inputs and one VHF into a single dual band antenna, but for the life of me I can't think of anything off the top of my head.

I have used many Comet duplexers and triplexer for both ham and commercial applications. They are well built units and they perform great. I have even worked with Comet to produce customized versions for commercial applications.

The unit will do exactly what you want and will work as you described. You will not be able to transmit on 440 with the 7000 in the configuration you have described but if you do you will be safe and nothing will break. Your radios will be safe from each other: this model offers 60dB of isolation between ports, e.g. if you transmit into one port with 50W (+47dBm) you will get out a maximum of .05mW (-13dBm) on the other port. A BIG signal from a receiver perspective to be sure, but it won't damage the other radio, just quiet (desensitize) it's input for the duration of the transmission.

Comet makes the best antennas and 'plexers in the business. I have no monetary ties to them, just a satisfied customer.

Thanks guys-I'll grab one this weekend

My EMCOMM rack arrived, and so far I'm pretty impressed with it. Looking forward to getting it up and running.

Correct.  The 1.3-170 port will only pass, you guessed it, 1.3 to 170MHz RF.  UHF would be severely attenuated with a very high SWR, possibly causing transmitter damage.

Isolation between the ports is a function of the high/low/band pass filters.  Different frequencies to different ports is the only way it can function.

Absolutely not.

A diplexor (duplexor here is a misnomer, but a common usage nonetheless) take a common port and separates RF by frequency band.  Triplexors, quadplexors etc just add additional bands.

No device is able to do what you are seemingly wanting to do, which is to connect multiple frequency-agile transceivers on the same frequency bands to a single antenna.

Except maybe a switch.  



 

Ok, so I left out the word "simultaneous"

Primarily I was curious about the consequences of accidental operation, e.g., if I transmitted on 440MHz from the 7000 while it was attached only to the lower frequency leg of the duplexer. The way this box will be set up, the 7000 will handle HF and VHF, and the 2821D will handle all UHF. HF will have it's own antenna-attached to my SG-237 coupler/tuner.

This weekend I will purge the 7000 of all UHF programming-or at least lock it out and inhibit tx. The 2821D will handle 70cm simplex and duplex, GMRS simplex and duplex, biz band simplex and duplex, and a few others.

Thank you for your thorough explanation

I have 2 Diawa dual port antenna switches in my go kit, one for HF and one for VHF. I run 2 IC-7000's. Usually one for HF and the other for VHF, however I wanted the fail-over capability should one rig go down.



I run both HF outs from the radio to the 2 terminal side of the switch...and the single port goes to the antenna. (basically bassackwards) Same with the VHF unit. The knobs protrude through the side of the box so changing each antenna to whichever radio is just a matter of flipping the switch.



The upside is each radio is isolated from the other and I'm not gonna let the mAjIK sMOkE outta my rigs.



To prevent keying up both rigs at the same time, I use a footswitch and headset/mic through an MFJ-1263, 2 radio-2 mic switching unit. Works well.

Tag.  Thinking about putting my IC-7200 + power supply and tuner into a box.  Was going to use something like AFM's Pelican box, but this iPortable solution looks really sweet.
Watching with interest, where's the pics?  

Sorry brother

I'll (hopefully) have some time this weekend to work on it. At the moment the empty box is sitting on my workbench...taunting me

Project pic added

Well, there are splitters and combiners.. but I think that's kind of outside the scope of this project.

OP you are missing a link to the Box webpage.

Very nice looking, CJan_NH!  Thanks for the pic.  After dragging my 7200 down to HomeSlice's place for Field Day, something like this would have been a lot easier to deal with.  

Two requests...

Can you show pictures of the backside?
Can you measure the height of each of the two radio slots?  I'm wondering if my Kenwood TS-480 and TM-D710 combo would fit in this box.

Thanks!

Thanks for the kind words guys

Haven't had time to finish the tuner mounting bracket yet, but I have been having a bit of fun with the new box when I can. In a couple of weeks it's going to another local ARFcommers home for a full-on test of our backup comms in the woods-using the box and my portable EMCOMM antenna as the base station. In the meantime I've been gathering Sordin tactical headsets, constructing wiring harnesses for remote PTTs, and evaluating various Bluetooth wireless adapters and dongles. So far I like the Pryme Bluetooth adapter best. You can see the adapter (second portable from left), along with the Sordin Bluetooth headset it connects to in the pic below:


I'll snap a pic of the rear of the box this weekend and post it. Here is a drawing from the iPortable site that provides the dimensions of the radio compartment. Sorry about the size:

The radio bay is seven inches tall by 8½ inches wide. If you click on THIS LINK the full size pic should open.

The shelves are adjustable to accommodate different sized gear.

I'm sorry I don't have a pic of the back right now-I'm still reeling from a laptop crash yesterday. As it turned out my backup is corrupt, and some of my files were lost

Should I add a link to this thread to the EMCOMM box thread? By not building this box from scratch, in my mind I sort of...cheated

Uh-oh... Houston, we have a problem.  My IC-7200 = (projections not included) 9 7/16in (W) x 3 3/4in (H) x 11 1/16in (D).  

Dremel!

I really wish I had stopped by to see these guys at Dayton if they were there...  If I can fit the 480 and 710 in here, then this is a winner.

Well unfortunately this box is out. The Kenwood TS 480 is too long . Back to the drawing board...

I'm really diggin this setup!!  only issue is there's not quite enough space for everything I want to put in it.

I'm thinking one of the smaller iportable boxes could hold a power supply, fm dualbander, and it's interface with the bigger one holding the HF rig, tuner and it's interface.

I too would like to see a pic of the back opened up.  I'm curios how accessible the back of the radios are.

73,
LM