Very poor results from HD7698P - Canadian TV, Computing and Home Theatre Forums

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post #1 of 52 (permalink) Old 2019-08-08, 11:19 AM Thread Starter
 
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Very poor results from HD7698P

Have had this antenna for a few years. Originally installed it on the roof with a tripod and worked well picking up local and distant US stations to the south. We had the roof re-done, and it has been in storage for 2-3 years. Meanwhile I have been using an old VHF log periodic on a tower nearby with two HDHomeRuns, one connected to the log periodic for dx, the other on a 4-bay bow-tie pointing north for locals.

I finally got the HD7698P up in place of the log periodic up about 40' on the tower, new feedline and I had also replaced the Wingard balun (part of the antenna) since it looked to be corroded, didn't want trouble.

With the fancy Wingard antenna up on the tower I could only get CKY and KNRR (both within 30-40km. Nothing else! Seems dead as a door-nail! Would get better reception with a wet noodle. If I pointed it north right at Winnipeg I could scan in CBC but it blocks and fades out sporadically.

CKY is about 40km away antenna pointing right at it!:
Modulation Lock 8vsb
Signal Strength 61%
Signal Quality 90%
Symbol Quality 100%

Brought the tower down and put the log perodic back on and reception is back the way it was.

Checking the HD7698P I find no shorts in the vhf and uhf elements, good continuity between connected elements etc. Not finding anything wrong with the antenna itself. Nothing obvoius with the balun/circuit board. Seems electrically the same as the old one (continuity checks etc). I didn't check operation with the old balun (yet) though. Connection between UHD and VHF conductors at the balun seems fine.

I must be missing something... likely an issue too obvious for me to see...! Where else should I look? Any ideas appreciated.

Was looking forward to better UHF reception to the south.

SBGH @ 46' for locals, Wingard HD7698P pointed south for US channels.
HDHomerun receivers, extend and connect.
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post #2 of 52 (permalink) Old 2019-08-09, 01:46 PM
 
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Quote:
I must be missing something... likely an issue too obvious for me to see.
You have to suspect the balun.
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post #3 of 52 (permalink) Old 2019-08-09, 06:53 PM
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Quote:
Originally Posted by Cham View Post
With the fancy Wingard antenna up on the tower I could only get CKY and KNRR (both within 30-40km. Nothing else! Seems dead as a door-nail! Would get better reception with a wet noodle. If I pointed it north right at Winnipeg I could scan in CBC but it blocks and fades out sporadically.

I must be missing something... likely an issue too obvious for me to see...! Where else should I look? Any ideas appreciated.
Quote:
Originally Posted by Red Knave View Post
You have to suspect the balun.
I also suspect the CB-8269 balun.

Winegard has a troubleshooting video. The idea is to check each section of the antenna with a conventional balun clipped to each set of wires for UHF and VHF.
How To Troubleshoot a Winegard Antenna Cartridge Housing
https://www.youtube.com/watch?v=TlQke5QYbng







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If you can not measure it, you can not improve it.
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Last edited by rabbit73; 2019-08-09 at 07:21 PM.
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post #4 of 52 (permalink) Old 2019-08-10, 03:17 PM
fgt
 
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I was wondering if some of the more knowledgeable members of the forum might be able to answer a question for me. I am interested in taking the feed from my antenna system and hooking it into a "box" which would then distribute my signal wirelessly to the various TV's and computers in my home. It sure would save a lot of time running coax all over the house which would be somewhere between difficult and impossible. Is there such a magic box? can I use an old computer modem? Just thinkin.....

DB8 35', rotor, CM7777 60' RG6
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post #5 of 52 (permalink) Old 2019-08-10, 03:40 PM
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Look into HDHomeRun Connect products.
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post #6 of 52 (permalink) Old 2019-08-11, 10:09 AM
 
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Also check out Tablo and Recast. All require another "box" at each TV (i.e. Roku, Firestick) but accomplish what you want.
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post #7 of 52 (permalink) Old 2019-08-12, 09:54 AM Thread Starter
 
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Ok, guess I'll have to pull the antenna down and do this check. Always have a few regular baluns around. It's a brand new CB-8269 but of course that doesn't mean it works. If nothing is grounded or shorted in the antenna harness or elements that would indicate only one likely possibility (unless the feedline or connector(s) is bad). Thank you for the information @rabbit73 and @Red Knave .
@fgt I use two HDHomeRuns and find they work relatively well. I use an Extend for nthe DX antenna (not working great right now) and a Connect for locals. It is likely a good idea to have ethernet with gigabit capability so there is lots of bandwidth headroom in your LAN even if they are 10-100 connections. I use one TV that uses wireless to connect to the LAN but it is 5.8HGz, I find the 2.4 wifi doesn't work as well. I am using a Uniquiti UniFi AP-AC-Mesh radio as an AP and it works really well. There are other options for network receivers that may be as good or even better, but these have worked well for me.

SBGH @ 46' for locals, Wingard HD7698P pointed south for US channels.
HDHomerun receivers, extend and connect.
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post #8 of 52 (permalink) Old 2019-08-25, 11:55 AM Thread Starter
 
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Well I pulled down the tower and antenna yesterday and checked as I did before putting the antenna up initially and it seems perfectly fine. No shorts or opens as I checked between where the balun fits in to the "harness" and elements it connects to. Nothing out of the ordinary. Connected the cable via the original balun to the UHF elements and I get nothing on the ground. Connected to the VHF harness and I get 7 and 12 like when up on the tower. When the antenna is "down" it is in a treed yard and I don't expect to get much reception, especially on UHF.
Just for fun I left the alligator clips attached to the UHF element harness and put the antenna on the roof. Now I get CBC out of Winnipeg but nothing else (antenna is pointed south away from CBC) which indicates it is likely working.
Thinking the balun/combiner is no good. I just spent $60 getting a new one and I have no incentive to spend another $60 on another one. Thinking I could invest in two 75 - 300 ohm baluns and use a separate combiner? Just have to make something up to connect the balun 300 ohm leads Cu) to the antenna harness(s) which is aluminum that won't react (galvanic). Maybe silver plated alligator clips?
It's a lot of work to take the tower up and down so I hope to do it once....!

SBGH @ 46' for locals, Wingard HD7698P pointed south for US channels.
HDHomerun receivers, extend and connect.
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post #9 of 52 (permalink) Old 2019-08-25, 05:34 PM
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Instead of Alligator Clips, perhaps you need something more permanent, such as fol. "Split Bolt Connectors", suitable for AWG14 thru AWG8:
https://www.amazon.com/SPLIT-BOLT-SE.../dp/B000H5XXHK

Alternatively, you might want to try some "T-Tap Splice Connectors", such as following [up to AWG10], which I only saw coming with a MALE SPADE type connector. At your local Auto Parts store, perhaps you can find some with a CRIMP type connector (instead of Spade Lug) for improved reliability. I would also recommend that you wrap the connection (and Baluns) with electrical tape to immobilize them so they don't move in the wind. [Use micrometer to measure your Antenna connector Wire Size to determine a compatible T-Tap size....apparently only available up to AWG10.]

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands

Last edited by holl_ands; 2019-08-25 at 05:54 PM.
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post #10 of 52 (permalink) Old 2019-08-26, 10:11 PM Thread Starter
 
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@holl_ands ,
Never thought of those type of connectors, great idea!
Can use that anti-corrosion goop used for aluminum cable in copper clamps such as inside breaker panels etc.
I can use the original enclosure to help support/protect the baluns, there should be quite a bit of room without the circuit board. Maybe self-vulcanizing tape would be good to use along with the electrical tape as well.
Do you have any recommendations on combiner? Is there a minimum distance form the baluns for placing it?

SBGH @ 46' for locals, Wingard HD7698P pointed south for US channels.
HDHomerun receivers, extend and connect.
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post #11 of 52 (permalink) Old 2019-08-27, 07:57 PM
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There is no minimum distance to VHF/UHF Combiner.

Fol. are VHF/UHF Combiners:
https://store.antennasdirect.com/antenna-combiner.html
https://www.amazon.com/Stellar-Labs-.../dp/B015ZSVDAW

FYI: Both units have "DC PASS" on the UHF Port if you chose to ONLY amplify UHF signals (as I usually recommend if not trying to drive 8 or more drops)....unlike [older, hard to get] "UVSJ" types, which have "DC PASS" only on VHF Port (which never made any sense).
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Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #12 of 52 (permalink) Old 2019-11-03, 08:42 AM Thread Starter
 
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Well, finally got to do some antenna work. I already had a mast-mount VHF/UHF combiner so I used it, put everything back up and found no appreciable difference in signals, still very poor. After some head scratching I realized I had not tried another receiver on that antenna. I also have a HDHomeRun Connect, so I switched them around. Now I get all the channels I was expecting anf the Extend on the bow-tie picks up the local CKY transmitter a few miles away and that's it. Guess it's receiver is almost dead... sensitivity is very poor.

I feel kind of stupid though not trying this earlier. Problem likely had nothing to do with the antenna, combiner, or feedline.
Odd thing is the old log-periodic I put back up seemed to work (but lately not that well either).

Now another problem... after a few days the Connect is losing channels on that same antenna. Was getting WDAZ and KX4 as well as cityTV off the back, now they are gone and signals from 12, 7, Global and CBC (off the back on UHF) are down considerably. It is like something is overloading the receiver to the point it could be damaging the front-end circuitry? It is currently dis-connected and I hope I haven't damaged it too!

I do have my amateur radio station nearby (hundred meters or so), and have a VHF transmitter to utilize the local repeater at about 146MHZ, and another digital transmission at 144MHz, both at rarely more than 5 watts. My HF station can go as high as 1KW but that is a long way frequency-wise from the television broadcast bands (1.8-21MHz).

I don't have a spectrum analyzer to monitor a wide band of RF, and I would be concerned leaving one attached to a feedline that could overload it, but one could just ramp up attenuation I suppose. Any ideas what I should be looking for here?

-C.

SBGH @ 46' for locals, Wingard HD7698P pointed south for US channels.
HDHomerun receivers, extend and connect.
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post #13 of 52 (permalink) Old 2019-11-03, 09:43 AM
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What was the receiver you had problems with, the one ur later saying may be poor sens?
Do you have an old computer or (or even a raspberrypi), that can run linux?


see some of my posts in the signal analyzers thread for some low cost but effective measurement ideas.
https://www.digitalhome.ca/forum/81-...ftware-22.html

had to do some antenna work myself yesterday AM. With all the recent windstorms, one of my antennas slipped,
and just so happened every time I looked at it from the ground, I couldn't quite tell what was up with it, cause it was always dark out
at the time I was eyeballing. Finally had some leisure time with the sun out yesterday and fixed it.

DB8E/VHF Yagi rotor FM Bandstop ap-8700 preamp 8way split LG lcd.
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post #14 of 52 (permalink) Old 2019-11-03, 10:31 AM
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Quote:
Originally Posted by Cham View Post
After some head scratching I realized I had not tried another receiver on that antenna. I also have a HDHomeRun Connect, so I switched them around. Now I get all the channels I was expecting anf the Extend on the bow-tie picks up the local CKY transmitter a few miles away and that's it. Guess it's receiver is almost dead... sensitivity is very poor.

I feel kind of stupid though not trying this earlier. Problem likely had nothing to do with the antenna, combiner, or feedline.
Odd thing is the old log-periodic I put back up seemed to work (but lately not that well either).

Now another problem... after a few days the Connect is losing channels on that same antenna. Was getting WDAZ and KX4 as well as cityTV off the back, now they are gone and signals from 12, 7, Global and CBC (off the back on UHF) are down considerably. It is like something is overloading the receiver to the point it could be damaging the front-end circuitry? It is currently dis-connected and I hope I haven't damaged it too!
Hello, Cham

That was a good idea to try another tuner when you had exhausted the possibilities in the antenna system. The tuner could be failing, but it could also be the power supply for the tuner failing, as in these two reports:
https://www.digitalhome.ca/forum/81-...ml#post2421569
Quote:
Originally Posted by glenner View Post
.....I did also post my current issue at SiliconDust forums and got the clue I needed... My issue was that my 5V power supply on the the SD HDHomeRun has started to go bad (it is 6-7 years old I guess having been powered on 24/7 all that time). This is not obvious at all! I simply never would have guessed that, even though I've replaced my fair share of bad power supplies before... But I had green LEDs going, and most all my channels in fact did work, except for most all of my strongest local stations (ie. CBLT, CITY, etc.). While local channel CTV actually did work the whole time for some reason...

In any event, I swapped in a new 5V power supply and presto, my CBC and other local channels are back!

So note to the wise, if things are behaving mysteriously erratic, check all you power supplies!

Problem solved. Thanks! -Glenner.
Quote:
Originally Posted by jsiddall
100% signal strength, no lock
I am having a hard time getting a set of local OTA HDTV channels from a specific tower about 15 miles away.

Signal strength shows 100% but still no lock and no picture, or a heavily pixelated picture.

UPDATE 4: I bought a cable long enough to run the antenna to a different floor where I had another tuner and that tuner worked great on all channels. Perfect quality. So having narrowed the issue down to the HDHomeRun I swapped out the power supply and problem solved. Signal strength is the same but lock happens immediately and the picture is flawless. Gaah. I hate SMPS and all the time I have wasted on them over the years. This one was a bit strange because so much of the tuner was working fine (like the network stack and parts of the RF chain) but clearly some RF stuff was out to lunch.
https://shop.silicondust.com/shop/?_...114.1572097742
Click on Replacement Parts
Quote:
I don't have a spectrum analyzer to monitor a wide band of RF, and I would be concerned leaving one attached to a feedline that could overload it, but one could just ramp up attenuation I suppose. Any ideas what I should be looking for here?
Try replacing the HDHR PS first. If that doesn't help, make a spectrum analyzer with a $20 SDR dongle and spectrum analyzer software:



Channel 9 is marginal, with just barely enough SNR above the noise. My HDHR4-2US Connect Duo does slightly better than my 32" Sony on that marginal channel:





Unfortunately, the HDHR tuner maxes out at 0 dBmV for 100%, even though TV tuners can handle stronger signals. In order to determine how strong a signal is above 100%, use a step attenuator to bring the signal down to 100%. The reading on the attenuator is how much stronger the signal is than 0 dBmV. If you don't have a step attenuator, use a series of inexpensive fixed attenuators of 3, 6, 10, and 20 dB. Even a splitter as an attenuator would give you a rough idea.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883

Last edited by rabbit73; 2019-11-03 at 12:38 PM.
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post #15 of 52 (permalink) Old 2019-11-03, 01:15 PM
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and that is why we interpolate from a straight line the strength and snr beyond 100% in
905shmick's bash script. I find it's fairly accurate.

https://github.com/shmick/TV_Stuff

DB8E/VHF Yagi rotor FM Bandstop ap-8700 preamp 8way split LG lcd.
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