Converting UHF Yagi to a VHF Antenna - Page 5 - Canadian TV, Computing and Home Theatre Forums

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post #61 of 104 (permalink) Old 2019-07-11, 02:02 PM
 
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1. Make certain you have properly terminated the unused L terminal.
2. You need more attenuation to get the FM signals to drop out. If you have a second HLSJ, cascade it. A single BT HLSJ isn't going to attenuate your local FM signals enough to make them non-receivable.

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post #62 of 104 (permalink) Old 2019-07-11, 07:14 PM
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FYI: My discussion re. likely (minor) SWR "issue" with RTL-SDR Full-Band FM Filter....which provides a whopping 50+ dB Attenuation all across the FM Band....I highly recommend it, bearing in mind that IF it is indeed a 50-ohm Filter, it might be doing something to either improve or [more likely] degrade the Antennas SWR....which may or may NOT be an issue (likely NOT if using Preamp):
https://www.digitalhome.ca/forum/81-...ml#post3073715

FYI: My discussion re. FMFool & FM Sensitivity vs Required SNR:
https://www.digitalhome.ca/forum/186...ml#post1369091

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #63 of 104 (permalink) Old 2019-07-11, 08:09 PM
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Quote:
Originally Posted by lenlab View Post
I ran my radio experiment.

First I hooked the VHF antenna to the radio to verify it was pulling in FM stations which it did nicely. FM stations up and down the FM spectrum were coming in loud and clear.

Next I used my Blonder Tongue ZHLSJ with "hi" and "lo" separators and fed the VHF antenna into "INPUT" and then fed the radio from the "Hi" plug. The results were the same. It did not do anything to stop my FM reception.

Hmmmm. Not sure what to make of it other than the ZHLSJ is not working at all? So I guess I need to try a real FM trap.
Your test does not prove the HLSJ is defective. It would be necessary to actually measure the FM attenuation of the HLSJ.

Did you ground the coax? If not, the FM signals can go around an FM trap/filter.

If you can not measure it, you can not improve it.
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post #64 of 104 (permalink) Old 2019-07-11, 08:46 PM
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Quote:
Originally Posted by lenlab View Post
I have an old Lenova laptop with Linux on it so it could be used for this. I see some USB TV tuners that might work and under $20. Not sure if they work with Linux.

What software did you use Majortom? Did you write a Linux program?
Assuming is from the current decade, that laptop would work perfectly, with the right kernel and application.
I haven't written any programs, but have contributed where I can, quite a bit.
My current laptop is a Lenovo T430 from ~ 2013
See below thread where we discussed this here.

https://www.digitalhome.ca/forum/81-...ml#post2919953

DB8E/VHF Yagi rotor FM Bandstop ap-8700 preamp 8way split LG lcd.
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post #65 of 104 (permalink) Old 2019-07-12, 08:48 AM Thread Starter
 
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Rabbitt73,

Interesting point about the ground. I believe the answer is the coax IS grounded. I'm not sure what the connector is called but I have one (actually one for every antenna on the mast) outside the house where I feed the antenna coax on one end and the other end coax goes in the house. There is a place on this connector to attach a ground wire which I have done and the wire then feeds to a ground which happens to be metal spike in the ground.

Also the antenna mast is grounded to a different metal spike.
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post #66 of 104 (permalink) Old 2019-07-12, 09:06 AM Thread Starter
 
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Majortom,

You have given me a couple of links to read and explore on implementing a spectrum analyzer with my laptop. I will be reading the links and may be communicating further with you on any questions via PM or the other forums. I would be interested in doing this spectrum look it might be fun and interesting. However it would seem to be complicated by needing the right USB tuner that works with Linux, spectrum linux software and Linux distro that it will all play with nicely.

My laptop is a Lenovo 3000 N100. It was running WIN XP at one time. Not doing much with it these days so putting it back to use to help my with my OTA issues might keep it from being put in the trash!
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post #67 of 104 (permalink) Old 2019-07-12, 08:06 PM
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Yeap, not a problem... My previous laptop was a Core2 Duo also.
So that lenovo should be fine.
Supported devices are listed in the Readme.
Which linux distribution are you currently using?
I am using Arch on this laptop, but have a few older ones with Mint on them.

DB8E/VHF Yagi rotor FM Bandstop ap-8700 preamp 8way split LG lcd.
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post #68 of 104 (permalink) Old 2019-07-13, 07:41 AM Thread Starter
 
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My Lenovo has ANTIX installed. However when I fired it up yesterday I found the bios (CMOS) battery was dead or dying as it gave me error messages booting up so I'm not sure how much more life this laptop has.

I have another old Dell laptop that I have to dust off and see if that may be a better choice. That as win XP on it.
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post #69 of 104 (permalink) Old 2019-07-14, 09:59 AM Thread Starter
 
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Holl_ands,

I tried reorienting my small 4 el folded dipole antenna towards the NYC transmitters and looked at 7.1 and the results were the same with strong signal strength and 0 signal quality. It is now back to its original orientation.

Next up I think I will buy from Amazon the RTL SDR and fittings to try it out.

I believe this is the one you are suggesting?

https://www.amazon.com/Broadcast-FM-...s%2C130&sr=8-3
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post #70 of 104 (permalink) Old 2019-07-14, 11:08 AM
 
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Did you read the description? The connectors are not F type. You will have to buy adapters, if they are even available.
Do a search and see what else you can find.

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post #71 of 104 (permalink) Old 2019-07-14, 11:38 AM Thread Starter
 
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Jorgek,

Great point about the adapters! I did mention RTL SDR and fittings in my post. By "Fittings" I was referring to the adapters which Holl_ands so kindly gave me a link to which I did not post as I did not think I needed to. They can be found on Amazon here.

https://www.amazon.com/exgoofit-F-Ty.../dp/B07D28P28J

I haven't found any full FM band stop traps that are available with F type fittings. MCM FM Band stop traps are the most desirable but are no longer sold and you can't even find them on Ebay.
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post #72 of 104 (permalink) Old 2019-07-14, 04:09 PM
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CMOS "Button" Batteries are usually RECHARGABLE and simply need to be recharged if Laptop has not been used for awhile. Leave plugged in overnight (and powered up, even if to error screen) and try again.

Li-ION "Button" Batteries also have a limited lifetime and MIGHT need to be replaced. Fol. Service Manual for Lenovo 3000-series sez you'll see it when you remove the rear cover....replace with same part number...or equivalent:
https://www.manualslib.com/download/...novo-3000.html [See pg84]
FYI: Fol. didn't even MENTION the "Button" Battery:
http://content.etilize.com/User-Manual/11977018.pdf

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #73 of 104 (permalink) Old 2019-07-14, 04:54 PM
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33F8354 Replacement Li-Mn Coin Cell Battery 3V 230mAh = CR 2032
https://www.batteryuniverse.com/lapt...n-cell-battery

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
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post #74 of 104 (permalink) Old 2019-07-14, 09:33 PM
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I would just go to the drugstore or elsewhere and grab a name brand like Eveready or Duracell

DB8E/VHF Yagi rotor FM Bandstop ap-8700 preamp 8way split LG lcd.
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post #75 of 104 (permalink) Old 2019-07-15, 09:16 AM
 
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The coin cells sold at drugstores are usually Li-ion or alkaline. How are they different from the specific laptop replacements which are Li-Mn.
Are Li-ion direct replacements for the Li-Mn?

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FTA, Openbox S9, 33” dish, PLL LNBF. Stab 90HH.
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