Mmmm yes, trouble is finding the proper capacitor then, I found a 1-5 pF (0 / I was told is impossible :eek:), and even that im not sure it is precise based on a test with a meter. Also not findable so far on the internet. Very small and capacitors come in newer forms (I assume you already know this ;))

The wire, f_connectors, and solder can be made quite accurately.

Putting it before the amp, although I tried it, is a PITA to gauge the results...;)

Mmmm yes, trouble is finding the proper capacitor then, I found a 1-5 pF
That's good for the range required. What I don't know, me not being an engineer, is how much it matters which type of capacitor is used.

There are lots of different capacitor constructions, and I've never found a really good explanation of why certain types are appropriate in some situations and not others. Even when of exactly the same capacitance values.

Cheers

That's good for the range required. What I don't know, me not being an engineer, is how much it matters which type of capacitor is used.

The document requests a PTFE foil trimmer. If you can get that type it would be best. If not, as long as the capacitor performs well in the UHF band, it should be fine.

There are lots of different capacitor constructions, and I've never found a really good explanation of why certain types are appropriate in some situations and not others. Even when of exactly the same capacitance values.

While capacitance is the unit of measure for a capacitor, there are other properties that are important. Some factors include physical size, maximum voltage, frequency range and is it polarized. Different capacitor designs can also have different possible capacitance ranges.

For example electrolytic capacitors are good for filtering DC power supplies as not only can you get large capacitance values without making it too huge (though they can get pretty big), but they can also handle larger voltages. The big limitation with them is that they are polarized and if you install them backwards (or apply AC to them) they can blow up.

roger1818,

as long as the capacitor performs well in the UHF band, it should be fine.

how can I tell - all the specs Ive seen ONLY give the capacitance range (no min below .5 pF), self resonant frequency, 2- voltages, Q at a certain frequency, turns, and temp. coeff....:eek:

You really ought to read the article then, and comment only after doing so.

OK. I read the article. It certainly does a good job of summarizing many things mentioned on this forum, but there really wasn't anything new presented.

I still stand by my original comments. Using notch filters before the pre-amp is only useful if you have a very strong local stations that are overloading the pre-amp and creating harmonic distortion. If you are just trying to balance the signal levels, placing it after the pre-amp will be just fine.

I also agree with him that it is better to have separate VHF and UHF amplifiers and combine the signals after the amps. Some pre-amps sold in North America do this all in one box.

Roger1818,

my idea was just to put into practice a POSSIBLY simple LOW-COST, channel specific filter for easy testing on reception....

mlord,

I tried the uvsj and for UHF only, with VHF port terminated, #8 to #12 are snowy but still very watchable (#10, #12 being the strongest), no change on #2 to #6 - albeit im doing all this on 4-bay bow-tie.

For VHF only, with UHF port terminated, all UHF digital signals are ZERO and the analogs are unwatchable. VHF signals are normal or near normal (without the uvsj)...

I assume this is normal?

thanks

Mmm.. so you see both VHF-LO + UHF on the "UHF" port ??

Weird. I never really checked the behaviour on them here.
Sounds something like an HLSJ, but not quite.

Cheers

mlord,

I see VHF low (same as though no filter was used) & VHF-HI (with some snow)...

this is like the 3rd such type of unit I try, and VHF still comes thru pretty strong, could it be some channels are just too strong????

Sounds to me like #2 & 6 are so strong that your TV is acting like an antenna and picking them up. Either that or you are using a peice of coax that isn't sheilded very well and is acting like an antenna.

VHF is normally very strong, and very easy to pick up. Even with a coat hanger, or an unterminated bit of coax.

This is the case where a combination of voltage and current baluns might actually be noticeable. :)

Is there an amp somewhere in this setup?

Hello,

I'd like to share my Satellite RG-6 with OTA. I have a CM4221 and CM7777 Preamp. Is using two diplexers made by Ideal from Home Depot good enough. I'm concerned about signal degredation, but these have a respectful 0.8dB insertion loss on the satellite side and 0.5dB loss on the Ant side, so they seem to be ok numbers wise. Should I use these or should I try to find the so called high performance Channel Master diplexers CM 4002IFD and CM 4001IFD, and are they worth me searching around for.

Anyone have experience with the Ideal diplexers from Home Depot?
Thanks.

Sat side (0.8 dB loss) isn't critical since downlead is after the LNA.
Ant side (0.5 dB loss) is as good as it gets.

Although you can share the downlead with Dishnet and old low-rez DirecTV systems,
most of the new HD DirecTV systems overlap the TV Band and can't share the downlead.

If you have the new HD DirecTV system, check into band shifting alternatives.

Can someone please direct me on how to make a stub filter for 11.0 (analog)?

For my location, the NM for 11.0 is 72.5 (db), and the power is -6.3 (dbm).

Much appreciated.

Well, I tried the Ideal brand diplexers and they don't work well for the combining part. I get some interference and it causes channels in the upper band to disappear. OMNI on 64.1 I get with 90% signal without the diplexer, and with it the channel has no signal. I went and got a CM4002IDF and used that in conjunction with the Ideal and all channels come in as expected, including 64.1. The CM4002IFD is vastly superior for combining the signals. Apparently it has more filtering of the LNB DC which can leak interference into the upper frequencies of the Ant side in the cheaper diplexers.

I did drop by there today, and there are -- correction -- probably a hundred or so UVSJs in that box! :)

http://www.digitalhome.ca/forum/picture.php?albumid=45&pictureid=1165
Mmm.. I guess there were more than a hundred, originally.. ;)

I was at Active Surplus again this past Saturday, and picked up another couple dozen of the UVSJs from that same bin. There're still perhaps 100 or so left in there now.

These are cheap, work reasonably well, and are also just the right form factor for conversion into coax notch filters and the like, too!

Cheers

I photo'ed this display in a Home Depot yesterday (sorry about the cell phone cam fuzziness). It shows the guts of a cheap dollar store splitter versus the PCB innards of an Ideal Splitter:

http://www.digitalhome.ca/forum/picture.php?albumid=260&pictureid=1656

Too bad some testers haven't seen any performance difference between them in the real world. ;)

It would be nice to see a real photo of that display.
The fuzzy blur above doesn't show us anything meaningful.

thanks.

Well, attached is a pic of a possible wire integration of two antennas into my existing satellite system. It surrounds a Microyal 3x4 switch. All comments are welcome. Again, this is just a thought on paper before actually doing it. Wondering the most if that would be the best location for the pre-amp...if one is indeed required, which would most likely be a Kitz type.

http://sites.google.com/site/maycreates/my-home-network/newsatsetup.png

I've read the FAQ, and I know that using different antennas can lead to headaches, but I figure these antenna are going to be separated by at least 10', and in different directions (one pointing N of NE for the CN Tower, the other pointing SE for Buffalo). The run between the pre-amp and its power supply could be more than 50', so it would be a trial and error. This is also taking into account that the install will be attic mounted, so grounding is not shown, though it would need to be considered if I do a rooftop mount.

Thanks in advance.

Marbles_00, the OTA side of it looks fine, but is your goal simply to have OTA and Satellite on one coax lead between the SW21 switch and your PC?

Does the Microyal switch cascade properly with an SW21 switch? Will your Twinhan card control not only the SW21 but also see the LNBs through the Microyal switch too?