The Best Uhf-vhf Combiner - Page 6

HLSJ

http://www.solidsignal.com/prod_display.asp?PROD=HLSJ

Yeah, the VHF high/low diplexers aren't really what I'm looking for because they usually cut off between 200 and 300MHZ and I need one that goes all the way to 512.
The 88/108 might work, but I think the high band gets closer to 90 than that, but I'll check. Thanks all for the input. If I happen to find one, I'll post it here.

I have a Radio Shack UHF 40" Boom Length antenna that I would like to stack on top of a channel master crossfire 3679 VHF/UHF antenna.

Would a Pico Macom UVSJ be recommended for this if I connected the channel master antenna to the VHS end of the combiner and the Radio Shack antenna to the UHF end of the combiner?

If not, is there a better option that I could use for a combiner?

Should work just fine. VHF section specifies out of band rejection greater than 30 dB.

Just be aware that one antenna will be providing UHF only and the other VHF only...

The Pico Macom HLSJ "HI" output does not attenuate any of the UHF frequencies used for OTA TV. I have tried it all the way up to UHF 68(800 MHZ) with no degredation of a weak analog signal.(85 miles out)

FWIW: Opposite of multiplexer is de-multiplexer....so how about de-diplexer???

But there's no reason a "diplexer" can't be used as either a splitter or a combiner.....

Not exactly what I wanted to hear. I guess I'm better off just using the rotor with the channel master crossfire. Thanks for the info.

Markertek is selling the Pico Macom for $1.38, stock up!

But it appears that their lowest shipping charge is nearly $10.

In my case, I needed about 10 of them, so it was cheaper than other places.

A Holland (Pico Macom) UHF-VHF Separator/Joiner (Diplexer), Model UVSJ. Less than $2.00 from Solid Signal.

How did you get the back off so neatly Wendell?

There's no need to. You use the UVSJ for that.

TechCab.com is selling them for $1.99
http://www.techcab.com/proddetail.php?prod=HLSJ

A knife blade was used to scrape away most of the white sealant then I used a small flat screwdriver to carefully pry off the metal back plate. The screwdriver has been filed to be very thin. This process did distort the metal back plate but I had no intention of trying to use the modified device.

FWIW, the Channel Master diplexer remains my favorite for outdoor use and the Winegard for indoor use. Too bad both have been discontinued . At any rate I would not hesitate to use a one of the Pico Macom devices.

The "HLSJ" makes a highly effective/economical Lo VHF/FM trap for someone seeking channels 7-51. The "UVSJ" can't do that.

Does any one have the chart of showing the roll off freq band pass/ band trap spec on this.

I was viewing it on an antenna system that uses seperate UHF and VHF antennas, but you make a good point for combined (full-range) antennas.

Thanks for the pictures, Wendell! All specs aside, you can really see the difference in construction.

I know this topic has been beaten to death. But I recently noticed this auction:

Radio Shack 15-2586

Which is listed as a 75-Ohm Coax VHF Low/UHF Combiner.

Must have been a batch of misprinted packages....

Yeah, I know it's an old subject, but I now have the capability to provide what Wendall asked for.

Got some new play toys and still had the object of last years spirited discussion in the "junk" box, so I did some analysis of the specific piece on hand.




Insertion loss on VHF is very good, less than .25 dB. UHF insertion loss ranges from about 1 dB at 470 MHz to about .5 dB at 800 MHz.

UHF signal rejection on the VHF port ranges from around 34 dB at 470 MHZ to greater than 40 dB at around 700 MHz.
VHF signal rejection on the UHF port is greater than 34 dB between 54 MHz to about 40 dB at 225 MHz with a dip below 40 dB in that range.

If I hadn't spent all my money on the new toys, I'd order a couple of other samples and test them, too, just to see how they compare.

PS89

Anything new in the UVSJ arena? I see the CM 0549 is still available from some online sources.

Are people using the Tin Lee products at all?

http://www.tinlee.com/Diplexers.php

What do cable headends use primarily?

There isn't going to be anything new, because there is insufficient demand for anyone to develop any new diplexers. The antenna business has always carried lots of, "new, old stock" items because lots of the old stuff didn't age on the shelves and there was no prospect of any improvements in design that were significant enough to justify replacing the old stock with newer stock. I've bought filters and combiners with manufacture dates that were 20 years old.

I was dismayed when I called Blonder Tongue a year or two ago and found that their ultra-fine UHF notchtrap, MWT-u, had been discontinued. I was told that they had only sold one the previous year and three the year before that, and so there was no point in replenishing their stock. I used to buy Pico BPF-UHF tunable notch traps, but they were old, new stock, and when they ran out, they said I'd need to commit to a purchase of 1,000 units to make it worth their while to produce them. Fat chance.

And not that this is a cheap passive device or anything, but I think the last commercial VideoCipher unit was manufactured in around 1991 or 1992. Even though the commercial market continued to maintain at least tens of thousands of commercial VideoCiphers in headends for over another decade, there was no need to manufacture any more because all the demand for replacements could be replaced with old, new inventory, used units, and repairs.

I don't know how Tin Lee stays in business, but it is just a matter of time before they go the way of Finco. Back before cable TV, Winegard, Channel Master and Jerrold used to make broad lines of passive equipment to serve the tens of millions of residences that were dependent on ther rooftop TV antennas for all TV reception, but today's market is a tiny fraction of that and it won't be getting any larger.

Maybe, stay tuned.

I just got a couple of prototypes of a new diplexer in yesterday (an original design from one of our engineers) that blew me away... At about 250# and being somewhat cynical, I don't blow away easily!

I've got some more informal testing to do tomorrow, then I'll send them on to our chief design engineer for his evaluation.

I don't know if we'll produce these for internal usage, for sale, or what, but they look even better than the Holland in some regards.


FWIW, looking back throught this thread, the photo that Wendall posted was a Holland UVSJ. The Pico-Macom/Tru-Spec is a different device and is very different.

The present incarnation of diplexer has insertion loss of 1 dB or less and out of band rejection of maybe 40dB. If someone invents one with zero dB of insertion loss and infinite out of band rejection, it will not be appreciably better than what we now buy for a dollar.

Great thread! I just found myself in need of one of these combiners. Solid Signal seems to be the most reputable place that still has these (not counting ratshack, theirs is ~$15 ). Solid signal still shows the Pico UVSJ picture with the caveat that it may be substituted with the Holland version. And lo and behold a Holland UVSJ was sent for my order. It does work just fine though.

I know this thread is old but I have a radioshack combiner the gold looking one #15-2586

Would I have any benefits getting a UVSJ?

The 15-2586 is a UVSJ.

The better questions would be "Do you need one?"