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Old 29-Jun-2015, 3:13 PM   #21
Flint Ridge
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ADTech, I did model them looking at 80 - 110 mhz to see what it was doing on the FM bands, that is where I got my info. And yes, install the high pass filter is the safe bet for sure.

looks like rabbit73 gave me a reading assignment which looks interesting and well help clear some more fog.

The tower is very nice. If I ever get everything done, I should post a retrospective in going after weak signals. But if you look long enough you can find towers "cheap".
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Old 29-Jun-2015, 3:47 PM   #22
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double post

Last edited by Flint Ridge; 29-Jun-2015 at 3:48 PM. Reason: double post
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Old 29-Jun-2015, 4:40 PM   #23
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Do you happen to have the gain, VSWR, and polar plots for that simulation?
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Old 29-Jun-2015, 5:35 PM   #24
Flint Ridge
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Do you want it on both antennas? The GH6 is so much simpler so that run does not take long. Here is the VHF antenna, is this what you were looking for?

SWR


Gain across FM - looks like I shaved the freq off the bottom, should be enough to go by.


Basic Plots 80 - 90 - 100 - 110 Freq is in upper left corner. Front of antenna is to the right.








Guess I should start a run on the UHF and come back later and check it.
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Old 29-Jun-2015, 6:52 PM   #25
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UHF - Higher FM gain to the rear. Any questions or need more info, let me know.









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Old 13-Jul-2015, 11:04 PM   #26
Flint Ridge
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Finally received the HLSJ today, with a heat index of 104, who knows when I get it mounted. Just to be certain and not engage in more wasted time etc.

Antenna in on HLSJ high side, out on combined, cap low side?

Thanks,

Flint
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Old 14-Jul-2015, 12:02 AM   #27
rabbit73
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Quote:
Antenna in on HLSJ high side, out on combined, cap low side?
That sounds right to me.

Quote:
Originally Posted by ADTech View Post
Kitz would need to provide you with a graph of the FM filter's performance, a photo reveals nothing about the filter's parameters. Sure, I can test it if you'd like. Haven't seen a sample of that model.

I'd just throw a HLSJ (cap the L input with a terminator) on the front end of the pre-amp and be done with it since you don't have any low-VHF to worry about.

FM usually causes problems on high-VHF first, but an amp, in the presence of any strong signal, can go into compression and cause weak signals to be lost. It's simply better to keep the strong signals out of the amplifier in the first place.
I agree with ADTech.

I do have a minor concern about HLSJs. If you put one in front of a UHF amp, will the high side, which is a high pass filter, introduce any significant insertion loss for the high end of UHF? It was never really designed for that task, and the specs of some say passes 170 to 600 MHz.
http://www.hollandelectronics.com/ca...-Diplexers.pdf
http://www.nsccom.com/productpdfs/btl/dsv.pdf

ADTech:
Please comment on my concern.
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Last edited by rabbit73; 14-Jul-2015 at 12:46 AM.
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Old 14-Jul-2015, 12:19 AM   #28
Flint Ridge
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Perfect. Thanks guys, now I just need to get it all together, mounted, aimed etc. Nice part is I am not disturbing my existing setup, so I can do a side by side and see what I have "gained".

Again, thanks.
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Old 14-Jul-2015, 1:39 AM   #29
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ADTech:
Please comment on my concern.
I tested the Pico and the Holland HLSJ units several years back. The specs are simply incomplete, there's negligible insertion loss up in UHF land. I'll see if I can dig up either the old data and/or the samples I had from back then and rerun them using my much newer and more accurate gear.

Google to the rescue. See this post: http://www.digitalhome.ca/forum/81-o...ml#post1265531

Holland HLSJ measured, Pico similar.

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Last edited by ADTech; 14-Jul-2015 at 1:48 AM.
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Old 14-Jul-2015, 2:44 AM   #30
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I ended up the the Blonder Tongue, just to confuse the matter.

If you are concerned I might be headed into a bad direction. I could proceed without them and then see the results and if needed, head back up and splice them in ahead of the amp.
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Old 15-Jul-2015, 8:40 PM   #31
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Quote:
Originally Posted by ADTech View Post
I tested the Pico and the Holland HLSJ units several years back. The specs are simply incomplete, there's negligible insertion loss up in UHF land.
Thanks for the data. I'm feeling better already.

Attached Images
File Type: jpg HollandHLSJFreqResp2.JPG (69.6 KB, 532 views)
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Last edited by rabbit73; 16-Jul-2015 at 2:13 AM.
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Old 20-Jul-2015, 1:28 AM   #32
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Well, weather broke. Was able to get it hoisted up and secured. Did not play around with the variable amp much, but it all works and is solid. Time will tell as always. SNR ratios on my old 194 pound Sony CRT indicates 28 - 32 SNR on these two channels. Can check for more detail on my Aero-M once it is not recording. Does what I needed.

Filter in front of amp, I've got it going through my new gear, but then also scabbed into my existing setup with another UVSJ hooked to my existing UHF. More upgrades in the weeks ahead... Thanks all, very helpful as always guys pointing me in the right direction. I really appreciate what you do.



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Old 20-Jul-2015, 2:46 AM   #33
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SNR on my weak #13 is 24 and 28 on #8
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Old 20-Jul-2015, 7:44 PM   #34
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Thanks all, very helpful as always guys pointing me in the right direction. I really appreciate what you do.
Glad that we were able to help, but you did all the work.

The GH6 looks very impressive up there, and it sounds like it is living up to its computer modeling predictions.

I like your photo of the GH6 with the car which shows how big it is. I couldn't resist the urge to add a caption; hope you don't mind.
Quote:
SNR on my weak #13 is 24 and 28 on #8
Which callsigns, KRCG CBS NM 7.9 and KOMU NBC NM 14.4 dB?
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File Type: jpg Flint_RidgeDHC GH6 (3).jpg (353.3 KB, 210 views)
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Last edited by rabbit73; 20-Jul-2015 at 8:09 PM.
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Old 20-Jul-2015, 8:40 PM   #35
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The photo work is fine. And yes the call signs are KOMU for ch#8 at around 14NM and KRCG for #13, which is really #12 which always confuses me. Makes me wonder if I cut the balun for the right channel. It's NM is all over the place, meaning depending on height. Supposedly it is best at ground level? Through trees etc. I think I'm around 6.4 at my height, but at ground it might be another 1.5 db. Seems to be holding well today. Did see it blip off once with a bunch of errors early in the day. Might be useful for me to actually work with the variable amp and see if it is at the best SNR, might be pushing it too hard. Are single digit VHF really hard to pull in?
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Old 20-Jul-2015, 9:15 PM   #36
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Are single digit VHF really hard to pull in?
If there's local electrical noise, yes. Otherwise, not that much. I can routinely pick up KOMU from our family farm about 56 miles ESE of Columbia, NM in the mid negative single digits with nothing more than our VHF dipole kit and a preamp.... unless the power lines within several hundred yards are radiating. The electrical noise, which is plainly visible on the spectrum analyzer, wipes out the very weak KOMU signal. KRCG is about 15 miles closer with an estimated NM of around 15 dB and doesn't get affected at the tuner.
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Old 20-Jul-2015, 9:24 PM   #37
Flint Ridge
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I need to fine tune the amp to eliminate that out of the mix. It randomly cut out again with tons of errors. Of course it is going through a highband filter an amp and then two UVSJ's. I could bypass some of my prep work I guess.
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Old 20-Jul-2015, 10:24 PM   #38
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And yes the call signs are KOMU for ch#8 at around 14NM and KRCG for #13, which is really #12 which always confuses me. Makes me wonder if I cut the balun for the right channel.
It confuses a lot of people. If you cut it for the frequency of the real channel, you're OK. Even if you didn't, you're still OK. Calaveras, who wanted the lowest loss balun possible, cut his half-wave coaxial baluns for his stacked 91XG UHF antennas for the middle of the UHF band. Then, he wanted to eliminate the combiner loss and connected the two 75 ohm lines in parallel, which gave 37.5 ohms. That was converted back to 75 ohms with a quarter-wave 50 ohm matching section.
http://www.aa6g.org/DTV/ABD/Antenna_Block_Diagram.html

The real channel is what the transmitter uses, and it determines what antenna you should use. The virtual channel number is a holdover from analog TV days, and is retained by the station to maintain continuity of identity for the viewer. Sometimes the real channel number and the virtual channel number are the same if the station stayed on the same channel.
.
To avoid confusion, an experienced user like you should only use the real channel number. If you use the virtual channel number, it should be in decimal form as, for example, 13.1. Some of the stations on a TVFOOL report don't even have a virtual channel number listed, only a real channel number.

The real channel number is for techs like us; the virtual channel number is what is displayed on the TV for the viewer.
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Last edited by rabbit73; 21-Jul-2015 at 11:52 AM.
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