Comparing Winegard PR4400 gain

[balm]

Depending on who does what model, i'm seeing the old PR4400 with low-UHF net gains starting at ANYWHERE from 9 to 12 dbi, which puts it ahead of most of the CM4228HD models (unhacked)

At mid-higher UHF they appear virtually equal.

Similar, at VHF-Hi, (#13), they appear equal


1. does this make any sense

2. has anyone modeled the newer HD4400, to compare with the PR4400

3. also, can we hack an HD4400 to improve lower UHF, and especially VHF-Hi (#13) ?

[larry15]

According to the charts on this page, you can improve low UHF on the 4228hd by adjusting the tine separation.

http://imageevent.com/holl_ands/mult...yrefl/cm4228hd

[balm]

I should clarify,

When I ran HDTVPrimer's PR4400 computer model, and plotted NET gain, it gave 12 dbi on the start of UHF

BUT, HDTVPrimer's graph comparing various antennas, shows the PR4400 starting at 10.5 dbi NET gain

So im not sure how the net gain was calculated on the website

EDIT: OK, thats resolved, it was due to the AGT

[holl_ands]

When I tried to run Ken Nist's PR4400 EZNEC file converted for 4nec2, I found that
AGT was off by several dB, with numerous Warnings and a few ERRORS. This is
very common for converted files. BTW: I collapsed ALL of the LD statements into
a SINGLE LD statement ("0" instead of a particular wire number means ALL).

Removing support wires (GW141/142/159/160) between Reflector and Front Spine
Wire fixed ALL ERRORS & Warnings (incl. Too Sharp an Angle). [They're superfluous.]
[If you insist on including them, try moving the attachments to the Spine Wire about
1/2-in away from the common connection point.]

AutoSeg(15) then brought AGT error down to 0.78 dB at 470 MHz...which could be fixed
by replacing the long twinlead feedline with just use a simple SOURCE wire at the center
feedpoint and then adjust SOURCE wire size for AGT=1.0. [Exercise for the student.....]

With 0.78 dB correction, I see a 470 MHz RAW Gain of about 11.4 dBi for PR4400, which would
be close to 10.4 dBi NET Gain for SWR~2.7....which is about 1.5 dB less than what you get...

In HDTV Primer charts, I see about 10.2 dBi RAW Gain and 9.6 dBi NET Gain for 470 MHz, which
is about 2 dB lower than cited above. (Maybe you were looking at dBd scale on the right?)

PS: Ken Nist's Net Gain calculations can be found at the top of the page in SIMS spread sheet.
Or apply the Mismatch Loss corresponding to the SWR on that frequency.

[balm]

Yes , thank you, I recently figured it out.

Did you run the program on VHF-Hi also ?

EDIT : I got a net gain of -12.72 dbi to 3.93 dbi in the forward direction ( I think gain is better out the back !)





And has anyone attempted a modeling the HD4400 and the HD8800 ?

Thank you

[lithOTA]

I haven't had time to really dive into the modelling software, but I can state from personal experience that the 4400 is downright awesome below RF25. I have an RF17 at 75 miles, 2-edge with a NM around -10. The 4400 gets this station when the Winegard 9022, AD 91XG, and AD C4 can't.
On the flip side, the 4400 really dogs above RF40. But if the feared DTV band contraction (down to RF14-RF30) actually happens, the 4400 will be a top choice, especially for only 20 bucks.

[balm]

I added a 1x2 mesh behind the PR4400 model in 4nec2, and significantly improved VHf-Hi (#13).... does this make sense in real-life performance ?

[300ohm]

does this make sense in real-life performance ?

Yes, if its wider than 28".

[balm]

Is it feasable to just tie-wrap the wire mesh onto the esiting reflector rods



EDIT: It didnt seem to make it more directional either ?

[300ohm]

Is it feasable to just tie-wrap the wire mesh onto the esiting reflector rods

Sure.

It didnt to make it more directional either ?

It didnt on uhf ? Thats odd.

[balm]

yes, youre correct, beamwidth went from 60 deg to 50 deg on 470 Mhz

[be236]

Originally Posted by lithOTA

I haven't had time to really dive into the modelling software, but I can state from personal experience that the 4400 is downright awesome below RF25. I have an RF17 at 75 miles, 2-edge with a NM around -10. The 4400 gets this station when the Winegard 9022, AD 91XG, and AD C4 can't.
On the flip side, the 4400 really dogs above RF40. But if the feared DTV band contraction (down to RF14-RF30) actually happens, the 4400 will be a top choice, especially for only 20 bucks.

When you said PR-9022, did you mean PR-9032? Also, did you compare with CM 3023/4248? I heard that CM 3023 Yagi is good for low UHF as well?

As for HD-4400.. if that's good for low UHF, then I would guess that HD-8800 would be a good +2 dBi gain above HD-4400 as well?

My distance channels I want are RF 17, 20 , 22, 26, 32, and 43.... so I am guessing RF 43 will be hard to get (it's at NM -10 dB).

[Mark_OB1]

Originally Posted by be236

My distance channels I want are RF 17, 20 , 22, 26, 32, and 43.... so I am guessing RF 43 will be hard to get (it's at NM -10 dB).

I see no RF43 on the TVFool Chart you provided.

Re: NMs of -10, in my limited experience (others may vary) signals that weak are difficult to lock without very high-gain antennas. On my CM4221 with AP8700 preamp, the best I can do is NM -7, and that's sometimes iffy. I have gotten NM -10 in the past, but couldn't lock it reliably.

A better antenna, or lower NF on the premap could probably improve that situation, but there's a limit to what you can expect. (Unless the TVFool results aren't accurately indicating the signal status at your location.) I.e., if you really want NM -10, you're gonna have to work at it.

[Mac060]

My first post, sorry if things don't go right.If you look at my TVfool at RF channel 42 it is this strongest from the North. The HD8800 would get channel 18 but struggle getting 42 part of the time. My most wanted channel is 20!

http://www.tvfool.com/?option=com_wr...ec120b68834087

I replaced the driven elements of the HD8800 with some homemade Fracarro PU8 zigzag elements. It pulls in channel 18 and 42 about the same from the same tower.

Channels 20 and 36 also share the same tower and are also about the same signal strength.

I don't think your channel 43 is much more than a long shot in the dark

Good luck with efforts.

[be236]

Originally Posted by Mark_OB1

I see no RF43 on the TVFool Chart you provided.

Re: NMs of -10, in my limited experience (others may vary) signals that weak are difficult to lock without very high-gain antennas. On my CM4221 with AP8700 preamp, the best I can do is NM -7, and that's sometimes iffy. I have gotten NM -10 in the past, but couldn't lock it reliably.

A better antenna, or lower NF on the premap could probably improve that situation, but there's a limit to what you can expect. (Unless the TVFool results aren't accurately indicating the signal status at your location.) I.e., if you really want NM -10, you're gonna have to work at it.

Did you try "Pending Digital?" That's where you'll see RF 43 (CBUT). It shows as -9 dB NM.

I have been able to get RF 43 once-in-a-blue moon when tropo conditions are right (typically when it's freezing cold outside.heh).

Also, I have been able to get RF 22 (CHAN) at -7.5 dB and believe it or not RF 20 (CHNM) at about -15dB at the same time about 2-3 times a week for several hours.

This is all with a home made M4 .. and before that I had a CM 4221 in the same location and was able to get those channels too.

Yes, I know that past 70 miles, picture lock is not stable, but even when I have not picture lock, their signal is about 40% and stable (I need 56% signal to get lock), so I figured I just need slightly more gain than my M4 to make it stable.

Another point of reference, look at RF 24 (at 62 miles out) and NM -5.7dB, I can get that consistently picture lock...