Will CM4221HD Get Upcoming VHF-HI Channels? - Page 2 - Canadian TV, Computing and Home Theatre Forums

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post #16 of 24 (permalink) Old 2010-02-23, 11:17 PM
 
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Quote:
It's too bad that we haven't seen any "real world" reviews of the C-5 compact VHF from Antennas Direct. As this antenna--if a decent performer--would be a good solution for those with balconies (apartment/condos) or those wanting a low-profile antenna system.
I and several others have posted reviews of the C5.

I related my November field trip here: http://www.highdefforum.com/962244-post12.html

Tom Balister has been posting comparisons of a variety of antennas at www.antennahacks.com including a comparison of the C5 vs. the WG Y10-7-13 and another that used the C5 as a baseline for comparisons of various 8-Bays on high-VHF.

Amazon.com reviews have been excellent for the C5. AVS member re_nelson posted his experience as one of the reviews there.

Feedback is out there and it has been very positive!
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post #17 of 24 (permalink) Old 2010-02-24, 11:32 AM
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Also we've been fortunate here to have JER3 as a member (he's AD's chief antenna designer/engineer) who shared quite a bit of technical info on the C5 with us in this thread prior to its product launch:

Antennas Direct's upcoming C5 VHF-HI Antenna

A link to the spec sheet of the C5 was posted in that thread too.
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post #18 of 24 (permalink) Old 2010-02-24, 04:05 PM Thread Starter
 
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This is the response I got from channel master

Scott, the cm-4221HD is not rated for the VHF signal. We have not speced this antenna for the VHF spectrum. I do know from personal experience that it does work in the VHF spectrum. I have a channel 11 that the cm-4221HD does pick up. You will need to try it out to see if it will work in your area.


This definately means I have to throw out my winegard UHF pre amp
when the transition happens and blow another 70 bucks for a VHF/UHF
amp. And hopefully there will be some kind of hack to increase reception
for channel 9 and 11.
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post #19 of 24 (permalink) Old 2010-02-24, 04:16 PM
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Since Man-Made Noise generally exceeds Thermal Noise in the VHF Band (esp Ch2-6),
amplifying VHF is very hit and miss...suggest you first try only amplifying UHF.

If the Winegard Preamp has VHF Bypass or Pass-thru you may be good to go....

And if not, add a VHF antenna via UVSJ UHF/VHF Combiner AFTER UHF Preamp.
The Pico-Macom and Holland UVSJs are DC Pass ONLY on VHF side, whereas
(reportedly) the R-S 15-2586 and Antennas Direct EU385-CF have DC Pass
on the UHF side, which you would require to pass power to the UHF Preamp.
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post #20 of 24 (permalink) Old 2010-02-26, 01:43 AM Thread Starter
 
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hopefully by 2011 there will be a top notch antenna being
sold for specific channels 7-51, right now it looks like you
can make some with some home depot equiptment, like I
heard the GH antenna with narods can be the best, But I'm
a noob with making antennas maybe I need to learn more,
But it would be easier if you can buy them, so no hassle,
but a hobby is good too, and it seems that in 2011 the GH
antenna will be the best choice for toronto over the CM4221hd.
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post #21 of 24 (permalink) Old 2010-02-26, 11:05 AM
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There are numerous antennas on the market specifically designed for Ch7-51+, including
the AntennaCraft HBU line and Winegard HD768xP line (#1 and #2 in Antenna Rec's, post#6):
OTA Antenna Chart/Tableau des Meilleures Antennes OTA - 17/05/2014
http://www.antennacraft.com/HBU.html
http://www.winegard.com/offair/vhfuh...as.php#hd7694p

In addition to these hi-gain, long boom Yagi's, Channel Master makes the CM2018 & CM2020:
http://www.starkelectronic.com/cm2008.pdf

RCA makes the small (1m x 1m), medium gain RCA ANT-751 (aka EZHD), which performs
about the same as the WG HD700R on Ch7-69 (after they resized the VHF element lengths):
http://www.winegarddirect.com/pdf/HD7000R.pdf

Small, lower gain antennas include the CM2016, WG HD1080 and WG FV-HD30 Freevision
(such as they are.....for short range reception).

BTW: Be sure to check the Canadian DTV database re whether you need to receive Ch2-6 in the
future. Some Lo-VHF Analog stations will simply change to DTV...and others shut down:
http://www.user.dccnet.com/jonleblan...da_TV_Stations

Last edited by stampeder; 2010-02-26 at 12:50 PM. Reason: fixed a broken URL
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post #22 of 24 (permalink) Old 2010-02-26, 06:11 PM
 
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Quote:
Originally Posted by Jase88 View Post
Nobody can say with certainty how reception will change post-transition. We do know that significant problems were experienced in the US with VHF reception after the transition.

Comparing existing analog reception may help somewhat--but there will be big changes to ERP in the digital world. So even that is a gamble.

Of course these VHF stations may apply for a UHF designation, or even higher ERP in the interim.

The best advice I could give is to do your VHF-antenna research prior to conversion, should a purchase and installation be required. Or--if you want to best protect yourself--go with a 7-51 antenna.

It's too bad that we haven't seen any "real world" reviews of the C-5 compact VHF from Antennas Direct. As this antenna--if a decent performer--would be a good solution for those with balconies (apartment/condos) or those wanting a low-profile antenna system.
tballister from Reno, Nevada, USA has conducted an interesting comparison between the C5 and other antennas. See: http://www.antennahacks.com/Comparis...F_Shootout.htm
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post #23 of 24 (permalink) Old 2010-02-27, 12:38 PM
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Yep that was mentioned in Post #16 Those kinds of tests are good food for thought.
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post #24 of 24 (permalink) Old 2011-10-06, 04:06 PM
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CM4221HD (New) 4-Bay Bowtie with Balun Hack Modification:

I posted 4nec2 simulation results at fol. webpage (incl. 4nec2 source file):
http://imageevent.com/holl_ands/mult...uhfnewcm4221hd
Measurements were from information posted by <smpowell55> and Balun Hack details
derived from a photo posted by <rabbit73> (see results webpage for thread references).

UHF Raw Gain=12.2-15.3 dBi. UHF SWR(300) under 2.1.
UHF F/B Ratio=19-33 dB and UHF F/R Ratio=15-18 dB.

Hi-VHF Raw Gain=3-6.6 dBi (FORWARD), but HIGHER Hi-VHF Raw Gain=7.7-5.0 dBi
(TOWARDS REAR!). Hi-VHF SWR(300)=EXCESSIVE, esp. on lower Hi-VHF channels.

Although NEW, CM4221HD is still optimized for OLD UHF Band (up thru Ch69),
wasting Max Gain peak on channels that are no longer available for DTV.
UHF Raw Gain is about same as older CM4221 with improved UHF SWR on
lower channels....and Hi-VHF Raw Gain & SWR, such as it is, has been degraded....

Super-Sized-4-Bays have better Gain on New UHF Band (up thru Ch51) and
don't have a Hi-VHF Gain Reversal problem.

More info & charts posted to CM4221HD Balun Hack thread:
http://www.digitalhome.ca/forum/show....php?p=1333088
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