I am not sure that the Blondertongue MXF Series (http://www.blondertongue.com/headend/bpf.pdf) filters are the best option for you. First of all they are professional quality and thus very expensive. Secondly, it has bandpass filters, so instead of blocking FM, it will pass single VHF channels (or the FM band). It is intended for systems where you have a separate antenna for each channel, which is great for professional systems, but a bit beyond most home installations.

If you don't mind spending the money, your best bet is probably a Tin Lee CR7-CH.FM - Bandstop (http://www.tinlee.com/FM_Products.php?active=2#ANTENNAFM) (be sure to request it be frequency shifted (91-108 MHz) for Channel 6 reception). This may be adequate on its own, or you may also need to add a Sharp FM Frequency Notch (http://www.tinlee.com/FM_Products.php?active=2#SHARPFM) tuned for 88.5 MHz.

My only concern with any FM Trap you may find is that it will be designed for an analog channel 6 and may cause problems with a digital channel 6. As you can see from Tin Lee's graph below for the Full FM Stopband, the 3dB point is somewhere around 82 MHz. If the curve for the Frequency shifted filter is similar, the 3dB point would likely be somewhere around 85 MHz, thus attenuating the chroma (86.83 MHz) and audio (87.75 MHz) carriers, but not the luma carrier (83.25 MHz), which an NTSC tuner should be able to handle. On an ATSC broadcast, which uses the entire 6 MHz band, this distortion could be much more troublesome. Now maybe an ATSC tuner might be able to handle FM interference and the FM trap won't be necessary, but maybe not. We won't know the answer to that until 2011.

http://www.tinlee.com/images/charts/Graph_11.gif (http://www.tinlee.com/Graph_ALL_FM_filters.php?active=2#graph6)

..They also now have a large stock of other weird splitters/combiners, using mixes of coax/twinlead. Including one that has a coax input, a VHF coax output, a UHF twinlead output, and an FM twinlead output.

If it actually filters those bands properly, then this could be used as a $2 FM trap for VHF. I bought one to try out.
No, it's useless as an FM trap. I tried it with VHF-6 just to be sure, and saw no improvement. Then I disassembled it, and traced through the minimal circuitry inside.

The coax input just feeds through a single low-pass filter (to cut out UHF) enroute to the coax output. There's a built-in balun to feed the UHF twinlead ouput, and the FM output connects to the input via a simple pair of resistors.

There's a second band-pass filter in there as part of the UHF output, but nothing to allow this beast to act as a basic FM trap for anything.

Cheers

I asked Tin Lee about their FM Traps and it looks like their CR7 CH.FMU/6 has:

1 dB loss on VHF-LO,
2 dB loss at 88MHz,
35 dB loss at 92MHz through 108MHz and
1.5 dB loss on VHF-HI and UHF.

A sharp notch may also be required for 88.5MHz, but other than that, this should work very well. The only disadvantage is it isn't cheap. ;)

I guess that means I have to decide on how badly I want clear reception on channel 6. I'm gestimating that a tunable trap and a notch filter would be $120 Canadian.

Well, first you could borrow/try the simple RadioShack FM-trap I have here. Those are cheaply available off eBay and other sources.

Hello,

I am hoping this is the correct thread to post this in.

I would like some help with my 'summer project'. I currently have a satellite dish (stationary as the landlord would not permit a motor) with 4 LNB's for FTA use (currently I primarily use it to watch NASA TV). I do want to keep access to the other LNBs even though my main use is for NASA TV. Those are hooked together via a 4x1 Diseqc switch so I have one cable going into my apartment. Where I live, there are two primary OTA broadcast sites. One is roughly north of my location and very strong so is easy to pick up (except for one channel which is fairly weak). The other is to the south/southwest and is more difficult to pick up (specifics are in the Ottawa OTA Reception and Station Status threads).

I currently have one DB8 antenna facing out of an outside window in my living room and part of the goal of this project is to get it out of the room along with adding a second antenna to pick up the second OTA broadcast site.

The landlord has two outdoor metal poles, although only one is easily accessible (the other is on top of a steep roof and was used for Look TV). On the accessible one, I would like to set up my DB8 antenna, which is currently facing the northern OTA broadcast sites along with another antenna in a stacked configuration (that would face the southern site). Looking at Post #16 in the OTA FAQ, the best configuration is to have two antennas of the same type. Therefore, I will probably go with either two CM 4221 HD's (shipped) or one DB8 (available locally) (including shipping they are roughly the same cost).

So, my first question is can I use a Diplexer and which model? (Note that the local store seems to carry the full line of ******** and Axing products in all FTA/OTA product categories but only carries Terk and TD antennas).

The end result would be to connect the 4x1 Diseqc switch to a Diplexer (or another switch) that would add the input from the two stacked antennas so all of them would go through one RG6 cable into my apartment. At the apartment, I have an FTA receiver (SV 8000 HD) which I use to record FTA and OTA programming and also split the signal to go directly into my OTA input on my TV. I do not currently use a pre-amp or any other type of power source to amplify the signal but it is possible to add that if I need it (the cable run is roughly 50 feet from receiver to dish and it would probably be another 20-30 feet from the dish to the pole with the stacked antennas.

Secondly, what other items should I consider in this project and are two DB8's overkill? (I already own one so I'd prefer to keep using it if I can).

Also, if anyone knows a local OTA installer for the Ottawa area or is willing to help me with this in person, please PM me.

Looking at Post #16 in the OTA FAQ, the best configuration is to have two antennas of the same type.

Off thread, but I thought I would point out that this is only true if the antennas are pointed in the same direction. If they are pointed in different directions it doesn't matter if they are of the same type. Often you want a higher gain antenna pointed towards the weaker stations and a lower gain antenna pointed towards the stronger ones.

Your best bet might be to find a new DisEqC switch, with a built-in OTA (antenna) diplexer. Very simple, and probably not very expensive at all.

Cheers

Thank you both for your quick replies. I hope the following is not off topic.

Looking at the options, it looks like the only option is a multiswitch (I can't find a 5x1 DisEqC switch). The only unpowered 5x4 multiswitch is an EMP Centauri 5x4, however as it is a multiswitch it seems to only receive signals from two satellites rather than all 4 (unlike a DisEqc switch which would receive all 4). That is assuming I am understanding the differences correctly (the multiswitch sets one LNB to odd transponders and another LNB to even transponders so there isn't a delay as the LNBs switch where as the DisEqC switch reads all transponders from each LNB).

So, it seems like the simplest solution is if I buy two diplexers so that I can pass the satellite signals through to my 4x1 DisEqC switch and the antenna signals from my ganged antenna (thank you for the note that I can use different types as that lets me use a home built antenna for the stronger OTA signals (CF) and the DB8 for the farther OTA signals (HC).

Hello Guys,


Can you put an antenna joiner after two preamplifiers ?

Let say I have a UHF and VHF. I want to join then after the output of the two just inside the house after my foundation wall (because of 120volts plug).

Then would be joined after let says 30 feet of coax before the two preamps?

I know I would have a lost but I don't think there is a joiner that lets DC pass on either side.


Thanks,


Intravino

Can you put an antenna joiner after two preamplifiers ?

Let say I have a UHF and VHF. I want to join then after the output of the two just inside the house after my foundation wall (because of 120volts plug).

Yes, that is possible. Just make sure you are using a VHF/UHF band combiner and not a broadband signal combiner. Not only will you not loose as much signal but it will ensure that the noise from the two amps are not being added. My question is why not use a pre-amp with separate VHF and UHF inputs?

I know I would have a lost but I don't think there is a joiner that lets DC pass on either side.

Tinlee makes one, but their equipment is more expensive than the consumer grade models. You also then need to make sure your power injector can support 2 pre-amps.

So, it seems like the simplest solution is if I buy two diplexers so that I can pass the satellite signals through to my 4x1 DisEqC switch and the antenna signals from my ganged antenna (thank you for the note that I can use different types as that lets me use a home built antenna for the stronger OTA signals (CF) and the DB8 for the farther OTA signals (HC).

In regards to diplexers, I was wondering if all diplexers are similar or if there are specific brands, models that I should be looking for? I've seen some diplexers, all of which claim to be good quality, ranging in price from $4 to $15 (for a basic 2x1 model).

I have used eagle aspen diplxers in the past and currently with no problems.

No real signal loss in signal strength either that has affected reception on anyway.

Good luck.

Hi there,

Last week a made several tests of UHF/VHF combiners.

The Pico-Macom and the Channel Master 0549 were tested.

I used my 4221/Archer VHF combo to test them and my Samsung TV. The amp used was the Kitz Tech.

Ok, these tests were not done in a lab with measurement instruments.

On of my digital channels the CM 0549 was always 1 bar better then the pico-macom ( 1 bar out of 10 bars ) on the Samsung tuner. On Ch 46 analogue Global the snowy picture was about the same.

So the champ is the CM 0549.

I decided to test something strange for fun.

I had a Daveco SAT/UHF/VHF combiner that I previously got at Raybel.

This combiner has a 5-860 MHZ inout on one side and 950-2250 MHZ on the other side.

So I put my 4221 on the 950-2250 MHZ side and my Archer UHF/VHF on the 5-860MHZ side.

Compared to CM 0549.

My VHF low and the VHF high were not affected

But the UHF signals were weird;

CH 19 SRC and CH 20 CBC were 1 bar lower then the CM0549

CH 22 WCAX 3.1 was 4 bars higher

CH 14 WPTZ 5.1 was 2 bars higher.

TQ 27 17.1: I had no signal with the CM 0549 and with the Daveco I got 2 Bars.

TQS 42 35.1: 2 bars higher.

WCFE 38 57.1 1 bar higher.

Global CH 46 analogue: with the CM 0549, I would say 40-50 % signal
Daveco Sat Combiner 70 %


I don't know what append with the UHF signals with the SAT combiner but it looks like the UHF signal at some frequency have less lost.


I went up on the roof to put this SAT combiner to my combo of 4228 and 10y13s for the American channels to see if I could boost my WVNY ch13 signal. I had no change between this the CM 7777 and the Daveco SAT combiner and Kitz Tech Amp.

Please discuss these results.


Cheers


http://www.digitalhome.ca/forum/picture.php?albumid=285&pictureid=1282

intravino those are Interesting results in the UHF band - there's clearly not a flat response curve across that band!

Either Home Depot or Canadian Tire (not sure which one I saw it in) are now selling an RCA "combiner" that is probably the same unit as that Daveco or similar.

I had a Daveco SAT/UHF/VHF combiner that I previously got at Raybel.

This combiner has a 5-860 MHZ inout on one side and 950-2250 MHZ on the other side.
Does it? xxxxxx Oh, wait, I see the fine print now!

It is behaving like an ordinary splitter, for the most part.

Thanks!

I don't know what append with the UHF signals with the SAT combiner but it looks like the UHF signal at some frequency have less lost.

It is blocking the signals from your 4221 antenna and using the UHF and VHF signals from your Archer UHF/VHF antenna. You would likely get the same results (or likely even better) if you removed the combiner all together and only used the Archer UHF/VHF antenna. The differences are a result of the differences between the Archer and the 4221 in receiving UHF.

It is blocking the signals from your 4221 antenna and using the UHF and VHF signals from your Archer UHF/VHF antenna. You would likely get the same results (or likely even better) if you removed the combiner all together and only used the Archer UHF/VHF antenna. The differences are a result of the differences between the Archer and the 4221 in receiving UHF.


I just did that 2 minutes ago and the answer is no.
I connected the Archer directly to the Kitz Tech amp.

The UHF part of Archer is super weak.

I get nothing in digital, no 2.1, 6.1, 17.1 and 35.1

I just get with the Archer: analogue 2, 6, 10, 12 and 17.

I just did that 2 minutes ago and the answer is no..

That doesn't make any sense. The UHF TV band is from 470-806 MHz. It should be passed by the ANT side and blocked by the SAT side. Maybe your combiner is defective.

It's brand new from Raybel but it could be defective. Anyways it's staying connected. I might go and buy one next week:p

Jean from Raybel said that this Devco combiner is much better then the CM 0549 and that their professional installer customers are all using this one now because of lower loss.

When he showed it to me I saw skeptical bur I got it for six bucks, I said : I don't have much to loose.

But what a discovery, I said it on the amplifier thread that I had an other controversy.:D