I think the instructions not to twist the twinlead are to prevent the antennas from being 180 degrees out of phase and cancel each other out. As for hyphenating terminals, I am sure it is a typo. maybe they were wanting to hyphenate twinlead and did the wrong word by mistake. ;)
Before this goes too far off-topic, I just wanted to say that hyphenation could easily come from a piece of software trying to fit more letters on to a line. Happens all the time when you copy and paste text from one document to another.

An HLSJ may attenuate FM on either side of the Y, not necessarily the side you expect it to... depending on how it was done internally. so you'd have to try it out. But i'm sure it's cheap to try !

The other consideration is the 0.5 dB max loss of the HLSJ is only for VHF-HI (175-216 MHz). Pico Macom doesn't certify its performance for UHF (they won't even certify that it passes UHF). Anecdotal evidence has shown that it will pass UHF and that the loss isn't too great, but YMMV.

I'm considering getting a Kitztech amp to use as a pre-amp, and since it doesn't have an FM trap built-in, I figure I should block the low frequencies I don't care about.


I would try it first without an HLSJ, you may not need it. :)

Would an HLSJ with a terminator on the "Lo" side be good enough

Probably.

An HLSJ, being a diplexer, will pass all frequencies above the transition frequency on the HIGH port. I've measured both the P-M and the Holland devices and they're both pretty good up into the UHF band.

I happen to have the frequency response plot handy for the Holland. The P-M is very similar although, if memory serves, the Holland is more efficient. Unfortunately, I wasn't focusing on an accurate measurement of the insertion loss in the UHF band, so the graph is quite indistinct in that regard.

http://i1203.photobucket.com/albums/bb390/AntDirect/HOLHLSJFreqResp.gif

Is there such a thing as a UVSJ with power pass onto the VHF side?

I'd like to combine a weak VHF station/antenna with strong UHF stations/antenna, using a preamp after the splitter on the VHF side.

Sure. Pico/Macom and Holland both make U/V diplexers that pass power on the VHF port.

do Cm join-tenna pass DC power, some say yes, some say no, CM doesnt seem to know ?


also ive read that UVSJs, pass DC power thru the VHF leg ONLY, and NOT the UHF leg, is this true?

Since CM discontinued the Jointenna products, they're not likely to be able to answer your question.

See previous post for UVSJ.....

Was in Menards last weekend and picked up a 75 ohm splitter made by Monster Cable. Retail is about $20.
Have 2 HDTVs in the house and want to split the antenna between the two. Have a preamp at the antenna (power supply inside where the cable comes in). I tried a splitter I had bought from a local big box retailer and got a terrible amount of insertion loss (attenuation), I am guessing 8dB thereabout. Only strongest signals were getting through. I also had a better one that did work too but maybe 5dB loss.
I installed the "Monster" spitter and it works great, no appreciable attenuation on the signal to each TV! Kind of like adding a distribution amp but is much more efficient, no power required.. :)
Maybe sometimes you actually get what you pay for?

*I used a 3GHz F-barrel as a signal check, switching between the splitter and barrel twice. Samsung TV signal meter.
-C.

edit:
It comes with one 75 ohm terminated F-connector

I suggest you redo your test with the preamp power inserter before the splitter. Maybe that first splitter was just not passing DC... Thus blocking power to your preamp

Splitter is in the circuit after the p/s so shouldn't make a difference. I did reverse the outputs on both units and there was no noticeable difference. I should have mentioned that. Originally I thought that the TV with the DC pass port would perform better but the cheap splitter(s) showed no indication of that. I don't have an accurate signal meter, just the ATSC tuner signal strength on the TVs menu(s).
Antenna is in my sig file, using a Phillips SWS52083W/17 preamp mounted at antenna, 50' Belden RG6 to p/s, then splitter, then about 30' same Belden cable to TV1, and about 50' white Cable Concepts 2160 RG6 from splitter to TV2.
I felt the less cable & connections between the preamp and p/s the better although there is a ground connection between the p/s and antenna, but not a lightning arrester.. I do have TV2 line running through the UPS surge protector and I do notice a bit of attenuation there (maybe 2-3dB) I can put up with dare I forget to unplug the cable and a lightning storm hits us. I by-passed the UPS when doing the comparison test...
-C.

You would not be likely to see any discernible difference testing with a splitter with an amplified signal and a TV set's internal "meter".

I'd expect the splitter to measure between 3.5 to 4.0 dB insertion loss, same as any decent two-way splitter.

After testing my A/B/C press-in switch, i discovered the signals "leak" from one antenna line to the other, and to the other, not very good :eek:

I connected only a single antenna line in one port, leaving the other 2 ports of the A/B/C switch empty, then i pressed the switch to the other ports, and to my surprise, the TV tuner signal meter was detecting some signal thru the empty (non-connected) ports, but nothing close to a lock for a picture.

I also tested another A/B switch, with a switch type mecanism, the result was not as significant, but still similar.

So now, im not sure where to get a "good" switch, and based on this thread, no other info is available

talk about co-channel interference :mad:

im not sure where to get a "good" switch, and based on this thread, no other info is availableI've only ever had one mechanical A-B-C coax switch that was clean (but I seem to have lost it somewhere in my shed!) while all the others I've tried over the years had varying levels of bad signal leakage and poor isolation. Thankfully I have no need for mechanical switches anymore since I use a Linux-based MythTV HTPC, with all switching done between the ATSC tuners electronically with no leakage or isolation issues.

online specs show 60-90 db isolation, depending on the make and the frequency range- what exactly is the significance of these, are they basically meaningless, and exaggerated

i would use HTCP, but i need the most sensitive tuner available, and these are only offered as ATSC receiver set-top boxes,

so far the computer TV tuners ive tested dont come close to others in terms of reception

they really need to make multiple tuner receivers

My own anecdotal evidence is that the mechanical A-B-C switches I've tried over the years (several brands) had nowhere near the isolation/leakage specs claimed, but I think I know why. I believe that mechanical wear and tear caused the internal contacts to wear out enough for problems to begin happening. I wish I could find the good one - it was extremely solid, could be mounted to a wall with screws, is about 4" x 5", and the sliding switch mechanism's handle fit in the palm of my hand. The others I tried over the years were a variety of smaller and flimsier designs.

thank you, i guess more trial & error is in order


i know LaSource (old RS) carries a model (Nexxtech)

it rates 60 db (or more) isolation, with gold plated contacts using advanced plate technology

Radio Shack 15-1968 RF Switch with Remote Control provides 1.5 dB Insertion and 50+ dB Isolation:
http://support.radioshack.com/support_video/doc70/70148.pdf

Teledyne RF722-12 is a Hermetically Sealed, voltage controlled RF Switch, providing very high
reliability (10 Million cycles), low insertion loss (under 0.5 dB) and moderate isolation (30+ dB for UHF):
http://www.teledynerelays.com/pdf/electromechanical/722.pdf
http://www.alliedelec.com/catalog/pf.aspx?FN=1185.pdf
"All" you have to do is mount it in a metal box with WIDELY SPACED Type-F connectors
and remotely control it via a 12-VDC power source (5-VDC also available).

Minicircuits ZFSWHA-1-20 provides 1.3-1.7 dB Insertion Loss and 58+ dB Isolation Loss.
http://www.minicircuits.com/pdfs/ZFSWHA-1-20+.pdf [Inquire re minimum order amount]

There may be other RF Relays with higher isolation if you search a bit more.....

If you want even higher isolation (90+ dB), consider a CCR-33 series RF Relay with SMA connectors:
http://www.teledynerelays.com/pdf/coaxialswitches/CCR-33LT.pdf
http://www.alliedelec.com/search/searchresults.aspx?dsNav=Ntk:Primary|ccr%2f-33|3|,Ny:True,Ro:0&dsDimensionSearch=D:ccr%2f-33,Dxm:All,Dxp:3&SearchType=0&Term=ccr%2f-33
http://www.alliedelec.com/catalog/pf.aspx?fn=1186.pdf&pageNum=1186
Then "All" you have to do is order SMA-to-SMA cable using RG-59 or RG-6, cut in half, attach Type-F's.

After testing my A/B/C press-in switch, i discovered the signals "leak" from one antenna line to the other, and to the other, not very good :eek:

I connected only a single antenna line in one port, leaving the other 2 ports of the A/B/C switch empty, then i pressed the switch to the other ports, and to my surprise, the TV tuner signal meter was detecting some signal thru the empty (non-connected) ports, but nothing close to a lock for a picture.

I also tested another A/B switch, with a switch type mecanism, the result was not as significant, but still similar.

So now, im not sure where to get a "good" switch, and based on this thread, no other info is available

talk about co-channel interference :mad:
I have a bunch of the a/b's, 3 per TV set and they leak more when the signals are stronger, say during good tropo events to the point where you can put the slider in the middle and both feeds contribute to the signal at the TV, good and bad depending on the channel. Only one that worked well was the optional 4 port that came on my Zenith in 1987. Good isolation and the TV remote worked it.