: Signal Amplifiers (Amps, Preamps, Distro Amps) - See Chart in Post #1



PanaMark
2009-07-23, 08:10 PM
unbelievable, I went to see what stations might be in so I went upstairs and screwed back in the coax lead for the antenna and plugged in my pre amp power source.
The damn pre amp mast portion is fried again.
I give up.
I went up on the roof and took it out, went back in and put my KitzTech amp back in the loop.
Friggin i'm so ticked. I took all precautions like unhooking it when I was not home and not using it during lightning storms, beefed up my ground for my mast.....
Time to try a new manufacture for a mast mounted preamp.

Ticked in London
Mark

goforit
2009-07-23, 09:21 PM
Mark:

Sorry to hear about your frustrations. I have used the HDP-269 and never had a problem (knock on wood). Not to say you did anything wrong, but is there something out of line? Is there a short anywhere? Is the coax OK? Is the coax shielded? Are you using a surge protected power bar? Beyond a defective pre-amp, I wonder if mlord or other amp gurus might have an idea to why your preamps keep dying? I don't know if this make a difference, but I got my pre-amp directly from Winegard.

otaedge
2009-07-23, 09:41 PM
Its got to be a short in the wire or you have been that unlucky?

If it is grounded then its got to be a short in your cable! Also unplugging and plugging it in? my pre-amp is left as is i never unplug and plug it back in when i want to watch tv! Its got to be a short i doubt you can be that unlucky!

i would be ticked too, check your cable connections i feel for you!

PanaMark
2009-07-23, 09:48 PM
thanks,
Nah, my set up is pretty st8.
One thing I did notice was yesterday was a decent tropo day. I was picking a few Buffalo station's and Erie. I did notice though on my local CFPL channel 10 analog the pictures was a bit fuzzy (overamplifcation). normally this station is beautiful and clear. Just before I went to bed last night when the tropo died and some rain came in, the picture went back to a clear state on channel 10. I did the usual last check for fringe channel's and found none so I unhooked the power source then unscrewed the coax from the antenna.
I did this precaution on account I thought some thundershowers might blow over in the middle of the night. It did not but it can't hurt.

Do any of you's think I am over powering the resistor's at the head of this pre amp? Perhaps on strong tropo evenings and then they just give up?
I don't get it.
I have had the KitzTech amp on for long periods of time and it does not seem to be affected.

If it was a short in the cable somewhere I would have power issues which I don't have. My power source for the amp has a bulit in protection and if a short is present it will trip until the short is resolved. In all three cases I have always have 18volts DC entering (to power source) on the pre amp mast.
Guys I have triple checked all my connections and cables.
It has gotta be over driving the pre amp mast with strong signals thus frying resistors

note: This last pre amp came st8 from Wingard too

goforit
2009-07-23, 10:08 PM
MarK:

The CHCH tower is 2.5 miles from my house and the HDP-269 has never failed. Occaisonally 15.1, which is off the CHCH tower, will show no signal- so I assume it's overload, otherwise things are fine. Ironically I don't have the pre-amp grounded like you. Maybe try contacting Winegard directly, they have a technical forum that is very active and reps respond quickly.

otaedge
2009-07-23, 10:46 PM
I am not no techno whiz nor do i claim to know too much but a few things i was told about grounding and have learned!

I ground my antenna on the ubolt assembly why?

Because if i ground it say on my tripod or at the base of my jpole then lightening or static electricity hits my antenna hits my preamp then hits my grounding cable (best conductor) and in theory follows my grounding wire as it is the best conductor and saves my TV via grounding block and ground( rod , water pipe or earth on electrical panel). This just saves me TV!

Grounding my antenna at the highest point of the ubolt assembly makes the electricity in theory follow that wire (best conductor) discharging it before my preamp which is below my antenna!

Now i cant be certian as to what happens as i am not an electrician or know the physics beyond high school theory and my so called common sense which is not always correct!

But for me i start my grounding wire before my preamp as i want to try and not only save me TV in grounding but also my preamp and other stuff!

Again this is my theory and what practices i employ i am not 100% sure if this common sense makes sense in the real world but it makes sense to me!

PanaMark
2009-07-23, 10:50 PM
just a small back ground.
I returned my first damaged pre amp to the place of purchase. They honored it no prob.
My first pre amp blew after 2 days of service.
Week later I put the second one in place, and it worked well but it failed after two days.
I spoke to Winegard directly and they sent me out a new one and I sent out the defective one back to them.
Que in third one. Worked great for a few days, perhaps a week or so, (with precautions as discussed before) and thus the same results.
I read on Wingard's forum of a gentlemen whom had lost his pre mast portion also similar to my experience (after a storm).
I don't get it........
I can't complain though as Winegard has been good to me and have listened.
According to them they have not had issues with this particular model.
Not to sure what my next step will be.
I'll have to sleep on it for now.

http://www.digitalhome.ca/forum/picture.php?albumid=120&pictureid=1201

http://www.digitalhome.ca/forum/picture.php?albumid=120&pictureid=1200
@otaedge
Guess what, when I beefed up my ground wire I also thought the same as you (I also consulted a Ham radio slash electronics guru at my work) and terminated the ground at almost the highest point well ahead of the preamp mast. Man you hit the nail on the head. I had that same reasoning. I'm desperate for an answer.

otaedge
2009-07-23, 11:05 PM
I hate to hear of such frustration yet i must be honest i find it hard to believe 3 in a row! Do you get alot of active weather in your area i know i am from toronto and last little while has been really bad here lots of storms more then normal!

Oh well sleep on it and when you get time send some closer shots i have seen your pics did a search just now but none show a close up of the grounding only the tie wraps for the birds and the antenna cant see much except a grounding block on the roof top and the wire from there at the bottom of your tripod where is the cable from another point before the grounding rod?

Phil81
2009-07-24, 04:18 AM
Yea this is hard to believe for the 3rd time! That pre-amp is known to be a good almost overload proof unit. Overloading shouldn't really damage the preamp it just makes reception worse. The cables likely can be ruled out as a cause. If any of the cables didn't have infinite resistance between the outer shield and inner conductor then not only would the pre-amp barely work, the reception without it installed should also be terrible too (shortout). I've noted your fantastic reception results when everything was working like it should so this is even more strange. Did you have this preamp installed before spring/summer came? Seems like it wasn't a problem when there was no lightning around. Could it be the new pcb baluns on newer antennas allow too much damaging voltage to pass down the coax compared to ferrite style baluns which might absorb most of it instead?

I don't know if Winegard has plans to get back to you about the last failure once they get your returned pre-amp, I assume they will try to test it and find out exactly what component(s) failed and what could have been the cause. I would really like to know why this happened to you three times myself! I have future plans to possibly test mount a cm4228a in tall pine tree to see if I could improve Cleveland market uhf's along with a cm7778 so I'm a little worried about something like this happening here.

I also wondered about static buildup on my vhf-uhf combo antenna above my CM mast preamp. There will still be static/energy build up on the antenna bowties or elements anyway. Those can't be grounded without destroying reception. Anyone correct me if I'm wrong about this, but whatever buildup that collects on the antenna elements normally would be absorbed and bled off to ground through the coax shield/braid upon it's connection to the preamp (pipe is already grounded where preamp is mounted) or at a coax ground block.

I grounded with I think 6 AWG copper (has 7 14awg strands of solid copper wrapped together) at the base of one of the tripod legs with a 25-30' long segment with 2 shallow bends to a 4.4' deep of 3/4" copper pipe. There is also another piece with an additional clamp going just through the wall 3' to the cold water copper pipe and bonded with the electrical panel ground/neutral. I started to unplug the power injector and remove the coax going to the tv when there is lightning within 5 miles though this year is almost rain free and drought like here. If a storm is expected to travel right overhead with lots of cloud to ground lightning then I might unscrew the coax that goes up to the mast mounted portion too.

john warfin
2009-07-24, 06:30 AM
quote:
"It has gotta be over driving the pre amp mast with strong signals thus frying resistors"

As a designer of RF preamps I'd say not likely. Resistors generally take 4-5x rating for long periods before any damage occurs. 100x more power than the Winegard circuit can supply.

Years ago I blew a half dozen diseqs before realizing the power source must be unplugged before connecting/disconnecting the antenna. Also my buddy blew a couple Wifi adapters by connecting a passive antenna (not designed to be powered, short).

It's almost always lightening (rare) or user error (common) that do in these pre-amps. Of course in this business you never know what will happen next. :)

PanaMark
2009-07-24, 06:37 AM
noted.
Someone mentioned that, but I always disconnect the power supply before any coax is unhooked.
I only started to unhook the coax with the third pre amp. In the first two cases they were always powered up.
Thank you for your input.
The search continues

john warfin
2009-07-24, 07:32 AM
If you end up having to trash it instead of refund/replace I'd be glad to troubleshoot and locate the failed device. Dying of curiousity as to what went bad. Probably a 10 cent diode or transistor.

I'm thinking of a DIY preamp considering the gross markup on these. Couple bucks in parts instead of $50 for fancy box.

Legacy2009
2009-07-24, 08:59 AM
PanaMark,

Sorry to hear about your woes. Just guessing here, but is it possible you're getting some interference from nearby power lines? (eg high voltage transmission line)

I myself am waiting for a Kitz Tech amp. Been about a week and not here yet, but I read that someone else waited 9 business days, so I guess it'll be next week.

peano
2009-07-24, 10:04 AM
I have an interesting issue with my Kitz. I have it mast mounted in a weatherproof enclosure with the 6V DC running up through a good quality wire. The mast and coax are grounded.

I find over time, say about 2 days, the amplification slowly degrades. I disconnect power to see if it is working and indeed it is, just not as strong as normal.

When I power it back up, it returns to full amplification. What could be causing this?

roger1818
2009-07-24, 10:44 AM
PanaMark,

I had almost exactly the same problem as you with the pre-amp built into my RadioShack Omnidirectional antenna. It would work seemingly fine for a few days and then suddenly stop working. I exchanged it a couple times thinking it must have been a faulty unit. The last time, the guy at the store gave me some grief so I agreed to test my cable. To my surprise there was a small short in the coax (I can't remember the resistance but it wasn't 0 ohms). I guess it was a weak enough short to allow power to get to the pre-amp, but enough of a short to cause the power injector to overheat and shut down over time.

I replaced the coax from my attic to my basement and it has worked fine ever since. Not sure if the cable got pinched when they were finishing the house or if the short was at the connector in the attic.

Have you actually measured the resistance between the centre conductor and the shield on your coax with everything disconnected or are you assuming (like I did) that it can't be a short since it works for a while?

holl_ands
2009-07-24, 10:56 AM
Also, was the Power Insertion Module changed each time???
It might have been the problem all along....

I would suggest using a VOM and measuring both DC and AC voltages on the
coax after disconnecting from the Preamp to see if there are any surprises.

exdelguy
2009-07-24, 04:42 PM
This amplifier works really well in the real world. It has a built in FM trap to which I add another 20db for strong FM stations 1 and 1/2 miles from my house.
There are other strong signals nearby. It does not overload like the CM 7775 and the Winegard AP 4800 do. It has 22db gain for UHF and 16db VHF. Like you I am trying to get signals from relatively low power transmitters from 50 miles away. I suggest this as an alternative because it is so easy to overload an amplifier.

mlord
2009-07-24, 06:25 PM
Well this is quite possibly not anything to do with Panamark's dying pre-amps, I did notice in the photographs that the F-connectors are not fully taped up.

Even the fancy ones used there (I use similar all-metal ones here -- love them!) are not waterproof. Wrap electrical tape snuggly around the entire F-connector (and a couple of inches of the coax) to seal it totally against moisture.

Cheers

okmed
2009-07-24, 06:32 PM
If moisture is the culprit find an electrician with a meggar and meggar the cable. Meggars generate 500 to 1000 volts so any weakness in a fitting or cable will show.

PanaMark
2009-07-24, 08:11 PM
Also, was the Power Insertion Module changed each time???
It might have been the problem all along....

I would suggest using a VOM and measuring both DC and AC voltages on the
coax after disconnecting from the Preamp to see if there are any surprises.
@holl_ands
I used a new P.I.M. each time
When I was confirming power I did check for ac and dc on the coax. Nah, no surprises. I did that check on account it is the same procedure I use when trouble shooting HVAC 24v circuits.
I appreciate every one's input.

@mlord
Indeed moisture will have to be looked at. I have convinced myself in running a fresh single length of RG 6 from my bedroom to the ground block. When the weather gets better each individual piece of coax will be taken off and inspected. More attention to weather proofing is a must and I am disappointed in myself on this lack of attention. I really thought I would get by, but it does makes sense that there may be a little bit of moisture getting though and with sensitive equipment this could case havoc.

Update:
I emailed Winegard regarding my issues and let me tell you, they do listen and care. They have passed on to me their opinions and things I should try to remedy the issue.
They are gonna send me a new unit, and to me this is above expectations.
They are genuinely concerned and would like to come to a resolution regarding my issue.
Honestly guys I have never seen this type of customer service in quite some time.
Props to Winegard regarding this issue.

Once again I cannot thank each and every one of you's enough for your two cents on this matter.
Take care
Mark