anyone know what kind of loss the jointenna has?

Well, congratulations, first of all!

I've measured as little as .5 - .6 dB or so, to around 2.5dB, depending on channel and how well the the box was tuned. That's on the bandpass port; its >30dB on the 'band reject' a.k.a. 'notch filter' port. ( FYI, I usually find I can tweak modest imporvements over the factory supplied tuning. But there's a caveat here which is that length of cable attached and impedance matching does influence the 'optimal' tuning; there's no way for a factory setting to account for the infinite possibilities of attached cable+devices).

Some test results from the 7th order chebychev high pass filter prototype I built, referred to around post #1177 (http://www.digitalhome.ca/forum/showpost.php?p=1201041&postcount=1177).

With an FM transmitter ~ 1/4 to 1/2 mi from me, installing the filter inside the house
on the input of the Zenith DTT-901, I don't lose any TV Stations.
My three Edge channels, WPXJ-DT 23, CHCH-DT 18, and CBLT-DT 20 are still stable, and WNGS-DT on VHF Hi Ch 7 is still visible
at like -66 dBm on the analyser, so it must not be too bad insertion loss wise.
Looks promising for when spring comes and I can insert it between the Antenna and pre-amp input, where it belongs.
Should be able to aim right at that tower and not be bothered.

Installed in a Bud Project Box, should be able apply some RTV or silicone sealant, etc.
http://www.digitalhome.ca/forum/picture.php?albumid=574&pictureid=3624
fm band as is, -30 dBm ref level, 10 dB / div, Centered on 98 MHz, 17 MHz Span
http://www.digitalhome.ca/forum/picture.php?albumid=574&pictureid=3623
fm band attenuated with high pass filter in place.
http://www.digitalhome.ca/forum/picture.php?albumid=574&pictureid=3622

Evening All,
I typically grab up antenna bits and pieces at flea markets, as I'm sure most here do. This past weekend I came up with piece I'd never heard of before, and I was hoping somebody might fill me in on some questions I have.

It's a PCT-NGNII-It1t--06 1-WAY TAP -6db

I've done the usual googling and found details here http://www.cencom94.com/gpage.html

But as I'm a novice, the obvious is alluding me. What is a drop tap and why are they used over just a splitter, or a distribution amp?

Thanks for any help.

Bobby

tap = you "tap" the signal with just a percentage of the total signal, leaving the rest to the main output.

That percentage you're tapping is rated in dB.

For a shared cable run in a big building, for example, you would not want to split the signal in half, then again in half, and so on, leaving the last subscriber with little signal left.

Under the same shared cable logic, you would not necessarily want to have a super 100x splitter where all subscribers are connected to. That could be a lot of wire you could save. You could decide to separate your runs in 16 legs, for example, and have each legs going through X apartments, use those taps between the units.

I hope I make sense, so I will love to be corrected if there's anything wrong here.

An even wordier explanation for this Holland 16 dB Directional Coupler, aka "Drop Tap":
http://www.cableandwireshop.com/16_db_1_ghz_cable_tv_antenna_directional_drop_tap_wallplate_ coupler.html

Hi folks,

Does any company make a flat top 1 Ghz splitter (2 or 3 way) that has power passing on any or all ports? I cannot seem to find one.

Thanks,

Bobby

Ideal's "satellite splitters", available at Home Depot, offer DC PASS on all ports.

Perhaps that might work.

Ideal's "satellite splitters", available at Home Depot, offer DC PASS on all ports.

Perhaps that might work.
I have had problems with Ideal pwr pass splitters used outside. They seem to be made out of a porous metal that absorbs water. I've had to go out and replace 3 of them, and i know for sure the connections were sealed.
Better to buy a good one if used outside. AD makes a good one.

Finally got around to putting the homebrew high pass filter (post # 1222) up top at the input of my preamp today. All my edge channels are still stable, and can tune Canadian stations CHCH-DT and CBLT-DT over a much wider swing of azimuth than before. While moving the rotor in a 360, it's actually pretty tough to lose CBLT-DT now, even when it passes by the nearby FM transmitter. Analogs look a little better too. Significant improvement achieved.

edit: bring on that summertime tropo;)
Some quality readings after installing the homebrew hpf,
from the pc based tuner which is the worst tuner in the house.
* - edge chs
** - history of multipath issues
ch call net C/N dB
7 WNGS-DT ThisTV 23.0
14 WUTV-HD FOX 27.5
18 CHCH-DT CHCH 17.0 *
20 CBLT-DT CBC 17.0 *
23 WPXJ-DT ION 18.5 *
26 WNYB-HD TCT 22.0
32 WNLO-HD CW 26.5
33 WGRZ-HD NBC 28.0
38 WKBW-HD ABC 21.5 **
39 WIVB-HD CBS 26.5
43 WNED-HD PBS 23.5
49 WNYO-HD MyTV 27.0

Hi All:

Just added a channel 9 jointenna last week (and moved an existing alternate attic antenna to become channel 9-dedicated) for the upcoming digital switch for CBET (CBC) Windsor. The jointenna seems to work well, with no apparent signal strength loss or multipath problem (all signals are strong and steady) and digital channels 7 and 8 seem unaffected.

Since CBET-9 is still in analog, I can do A-B antenna tests with simple eyeballing, and something unusual caught my attention. With my previous antenna (pointed 35 degrees off-axis toward channels 7 and 8), channel 9 comes in around a 6 out of 10 in analog. With the now-dedicated channel 9 antenna going through the jointenna, it comes in around an 8.5-9 or so, but the picture has much more contrast to the limited snow present, while the picture going through the previous antenna (even though snowier) is much softer overall. It's almost as if the tv's sharpness control is turned all the way down on the previous antenna, while turned all the way up with the dedicated channel 9 antenna going through the jointenna. Or, it's almost as if the jointenna is slightly off-tuned.

I noticed re_nelson's post today at #26 in the Winegard 9032 thread (http://www.digitalhome.ca/forum/showthread.php?t=137678&page=2) about trimming the caps in his jointenna:

You'll likely be interested in the waveforms I saved a few weeks back that Trip Ericson archived on his RabbitEars site. This configuration was the 91XG and C5 aimed at Cedar Hill (site of Dallas area transmitters) and the Y10-7-13 (aimed north for KXII channel 12). The only waveform not flat across the top is KTVT's RF-11 signal due to the JoinTenna 0582. I've since tweaked the trim caps in the device and restored 11 to a nice flat top without adversely impacting channel 12.

After reading this, I thought I'd ask re_nelson (and the group in general) whether my jointenna could be slightly out of tune, and whether it's easy to tweak the trim caps yourself without any specialized equipment (and if so, how it's done) such as by simply eyeballing the picture on analog 9 and checking signal strengths on digital 7 and 8. In the digital realm, this would never be apparent to me (as it would probably never show up on my tv's signal strength meter), so I was wondering whether I should attempt a trim cap adjustment while channel 9 is still in analog. On the other hand, if the adjustments are more likely to get messed up if I attempt to adjust, I'd be inclined to just leave well enough alone, since my signal should now be plenty strong for the upcoming digital switch on channel 9. Also, perhaps this is just a normal characteristic (for analog stations) of using a jointenna.

Thanks in advance for your comments.

Hi folks,

Does any company make a flat top 1 Ghz splitter (2 or 3 way) that has power passing on any or all ports? I cannot seem to find one.

Thanks,

Bobby
Most "SATELLITE" RF Splitters (well beyond 1 GHz) have DC PASS on one or both ports.

Does any company make a flat top 1 Ghz splitter (2 or 3 way) that has power passing on any or all ports? I cannot seem to find one.

Just FYI...I finally found the flat top splitter I was looking for here:
http://www.aerialsandtv.com/onlinesplittersandamps.html#ExternalSplitters

Bobby

That company is in the U.K. so I hope they have reasonable shipping costs for you. :)

DirecTV "SWM" RF Splitters might be just what you're looking for:
http://www.sonoradesign.com/images/MSAT-Splitters.pdf
http://www.sonoradesign.com/images/sheet_sws_splits.pdf
http://www.sonoradesign.com/home.php?cPath=49&target=homeowners&osCsid=6inn9b98ckshujikjomnipcar0
Note that these are specifically designed for MoCA enabled households, with a port-to-port
isolation much less than the high isolation found in typical Cable RF Splitters.

FYI: MoCA "Whole Home Networks" is available in newer DVRs, Cable Boxes, PCs and some External Storage
Devices for internal distribution of either user supplied files or redistribution of provider provided programs.

I'm getting some interferance on Channel 6, still haven't determined what it is. Will be investigating this weekend. If it's FM interferance, will be looking for solutions, since I don't want to use the trap on the CM7777, as I will be pulling in FM signals on this setup too.

In order for an FM trap to be effective, it usually needs to be installed before the first active electronics device, ie, amplifier.

Are there no other options i.e. after the pre-amplifier?

Inter-modulation occurs in the first active device (transistor, etc). Therefore, filters should be used before that first stage.

Looking at your location, I don't see any licensed FM stations anywhere near your location that would likely interfere with channel 6.

Poke around this weekend and see if you can get any additional information.

Your cm7777 should greatly attenuate FM but not necessarily kill it completely, especially if you're having trouble with interference and FM end up being the culprit (it usually is)

You should give the cm7777 trap setting a try, and see what it does to channel 6 and FM before and after the change.

Regarding how to track down the source of the interference on that analogue NTSC station (and thus decide on a suitable solution) here are a couple of useful threads as resources:

http://www.digitalhome.ca/forum/showthread.php?t=105230

http://www.digitalhome.ca/forum/showthread.php?t=115744