Reception help in Southwestern Ontario

[digitaljunkie]

Hi Everyone,
New member here. Been dabbling in OTA for the last few months and would appreciate any thoughts you may have for me.

First, my set up is as follows. 91XG mounted 35' AGL on my rooftop. CM7777 preamp, 75' RG6 with CM rotor.

Here is my TV Fool report:

http://www.tvfool.com/?option=com_wr...dfaf709ce25467

My main question is RF 29 Global and RF 14 CITS which are each a nightmare to get a lock on. It almost always is viewable but with heavy pixilation other than in optimum conditions. RF 13 CKCO is a no go except in the strongest tropo conditions. I presume there must be a land mass blocking the signal path.

I've had very good success with the top 4-5 Detroit stations when conditions dictate but the locals are very inconsistent.

Any thoughts would be appreciated.
Thank you!

[ADTech]

RF 29 has a mere 30.7 kW in your direction at over 62 miles and is on a short (682' AGL) tower

RF 14 has a measly 1700 watts in your direction at 45 miles and is on a bit taller tower (967' AGL). That's about as much power as a high-output hair dryer, to put it in perspective.

You're well out of either station's expected coverage area. Sporadic reception, if any, would be the expectation. You could conceivably stack a pair of antennas to pick up perhaps 2-2.5 dB of gain and swap out to a lower noise preamp, but the payoff for the effort would probably net you, at best, about a 3 dB improvement in the system noise figure. That might take your reception from perhaps 95& unreliable to 85% unreliable.

CKCO on RF 13 is a VHF station, you have a UHF antenna design that was never intended for VHF and I've never characterized or measured its VHF performance. However, I did notice one time a while back that it tended to pick up VHF a bit better when its boom was perpendicular to the signal direction, you might play with that idea since you have a rotor.

[digitaljunkie]

Thank you for your reply ADTech. That info helps me. Couple follow up questions to what you've supplied.

- Is there a way on TV Fool or otherwise for me to determine transmitter height that I'm missing?
- That makes sense as far as the perpendicular arrangement for VHF. I'm able to consistently get RF 10 CFPL utilizing this method. That is why I was hoping there may be a way to do the same with RF 13 but no luck.
- With regard to my American options, would you agree that I'm doing about as well as can be expected? I'm getting reception approx. 40-50% of the time which I think is quite good. If there would be a way to increase that consistency I'd be interested in that as well.
- With the stacking option, would that consist only of adding another 91XG? I also have one of Denny's HD Stacker units.

I was not aware how to decipher the Eff ERP so thank you for that.

Thanks
Jamie

[ADTech]

- Is there a way on TV Fool or otherwise for me to determine transmitter height that I'm missing?

No. While that data is used by the simulator, it's not present to the user as separate data. I pull that info from the FCC or IC's licensing database or from rabbitears.info (which pulls from the FCC database).

That is why I was hoping there may be a way to do the same with RF 13 but no luck.

You really need a VHF-capable antenna to pick up that weak of a channel 13 signal.

- With the stacking option, would that consist only of adding another 91XG?

It can be done with any two identical same-band antennas. The antenna you referenced doesn't count.

I was not aware how to decipher the Eff ERP so thank you for that.

That has to do with how the transmitting antenna's pattern and your angle relative to it (if the antenna is directional).

[WIRELESS ENGINEER]

The 91 is a typical yagi design thus most of its gain is on the high channels
The channel master 8 bay has much better performance on the lower UHF channels

[digitaljunkie]

Hi Again
I'm wondering if anyone can advise if the Antenna's Direct VHF retrofit kit would be of benefit as an addition to my 91XG?
Thank you

[ADTech]

For channel 13? No, you need a LOT bigger high-VHF antenna to have a shot at that station.

You could try adding a ClearStream 5 (requires U/V combiner) which is roughly ofcomparable performance to a 5-6 element Yagi but in a compact form factor. It would be right on the edge according to the available math. The next step up would be to go with a more conventional high-VHF Yagi of which there are few options. Most notable option appears to be one that MCM imports from China. I haven't tested it but it is available and is more directional and is higher gain than a C5. It's also a lot larger.

[digitaljunkie]

Thanks again ADTech. No I wasn't thinking for 13 but for 10. I get 10 about 80% of the time through the XG. Was just hoping to give it a little more oomph to minimize dropouts.

[rabbit73]

The Antennas Direct C5 should improve the reception of CFPL 10, but it doesn't have enough gain for CKCO 13.

If your 7777 is the original version with separate UHF and VHF inputs, connect the VHF antenna to the VHF input, with the switch set to separate. If your 7777 has only one input, you will need to combine the UHF antenna and the VHF antenna with a UVSJ UHF/VHF combiner (AKA diplexer) before the preamp.
http://www.solidsignal.com/pview.asp?p=uvsj

https://mjsales.net/products/tru-spe...ant=1198505857

with weatherproof housing:
https://www.antennasdirect.com/store..._combiner.html

do not buy the MCM 33-2230 combiner unless you are willing to take a gamble on quality control problems:
http://www.mcmelectronics.com/produc...-2230-/33-2230

The MCM 30-2475 can be used for 10 or 13:
http://www.mcmelectronics.com/produc...-2475-/30-2475
but the 30-2476 has a little more gain for 13:
http://www.mcmelectronics.com/produc...-2476-/30-2476

[digitaljunkie]

Thank you Rabbit. I was not aware of either of those two options. Appreciate it.

[ADTech]

Based on the data on your plot, the VHF kit should be adequate. However, I'm going to assume the data is, at best, ambiguous due to an imprecise location and the rating of "2-edge".

[digitaljunkie]

ADTech you're referring to rf 10 i presume?

[ADTech]

Originally Posted by digitaljunkie

ADTech you're referring to rf 10 i presume?

Yes, I was responding to your earlier clarification.