Winegard HDP-269 DOES have an FM Trap!

[Piggie]

Low and behold, despite the fact it's totally unadvertised, the HDP-269 indeed has a built in FM trap that is -12db, matching it's gain, that is fixed and always on (it can't be turned off).

Here is the email from Winegard's engineer, Hans Rabong.

My question to Hans was can the HDP-269 be used as an FM antenna system amp. Obviously it can not!

> The HDP-269 preamplifier does have a 12dB FM fixed trap built into it so
> you will have to use an AP-3700 preamplifier with the FM trap switched
> out.
>
>
> Cordially,
>
> Hans Rabong
> Tech. Service Manager.
> Winegard Company
> 3000 Kirkwood St.
> Burlington, IA 52601

So for the last year I have been suggesting people not buy the HDP-269 that only needed a small amp, yet lived near an FM station and suggested the AP-8700, which has a fixed and tunable FM trap.

But this new information makes that moot and makes the HDP-269 maybe the best small amp out there. With it's small gain 12 db and low noise 3.0 but really shines in it's tolerance to overload taking signals as strong as minus 15 dbm according to Hol_ands chart. That is a pretty strong signal meaning it can be used in fields as strong as 60 db NM range including the antenna gain to overcome coax loss.

As a disclaimer I do have nearly instant access to Hans and Winegard does have me currently comparing a couple of their antennas. The only benefit I get from this is I get to keep the antennas. Which in this case won't do me a bit of good after the test (too small). I will be doing a lot of testing out of the car, which leads me to another post.

 

[EscapeVelocity]

In the Winegard product book, it clearly states that the Winegard 269 does not have an FM Trap. Someone opened one up and did not spy one. I see if I can locate the thread and post a link...with that information.

 

[Piggie]

In the Winegard product book, it clearly states that the Winegard 269 does not have an FM Trap. Someone opened one up and did not spy one. I see if I can locate the thread and post a link...with that information.

I looked on their website, including their install pdfs and not where does it say it has or doesn't have one.

I need to take mine apart. hmmmm.. I will be interested to find out.

=========

Well the bottom cover pops off pretty easy, but I need a nut driver to see the side of the circuit board with the parts. It's late, the shop is dark and I have to be up in 6 hours and washing dishes. When I get home tomorrow I will take the nuts off the f-fittings so I can look at the board. Then if the trap is done on the circuit board, I am not sure I can tell what I am looking at.

But as I said for a long time I didn't think it had a trap..

 

[EscapeVelocity]

Winegard HDP-269 Revisited

Inconclusive, still. Id say, but still questionable.

 

[No Static At All]

I have received e-mails from 2 different contacts at Winegard stating that the HDP-269 does in fact have an FM trap. I wish I could test this at my location, but the signal strengths are too strong for pre-amp usage.

I believe Tower Guy has inspected the circuit board & found no evidence of a trap, so I guess the jury is still out.:argue:

 

[Tower Guy]

I have received e-mails from 2 different contacts at Winegard stating that the HDP-269 does in fact have an FM trap. I wish I could test this at my location, but the signal strengths are too strong for pre-amp usage.

I believe Tower Guy has inspected the circuit board & found no evidence of a trap, so I guess the jury is still out.:argue:

I can confirm that observation. I have an FM station .8 miles away from me. With a 4228 antenna and an HDP-269 I needed an external low pass filter to eliminate overload. The AP-4700 that I had previously worked better than an HDP-269 until I added the external low pass filter. (UVSJ) This was hard to forget because it took a climb up my 120' tower to add the LPF.

Yesterday I opened up a AP-2870. I wanted to verify that it had two amplifiers, one for VHF and one for UHF, which it did. The use of two amplifiers would make the AP-2870 very immune to overload in a mixed VHF/UHF city. Depending on the VHF/UHF mix, the AP-2870 could equal or even outperform the HDP-269. For instance, an area with three VHF and 3 UHF stations would work best with separate antennas and the AP-2870 as opposed to an all-channel antenna and an HDP-269. With two of a kind, the HDP-269 and AP-2870 are about equal.

In Albany, NY there are 4 VHF and 3+ UHF stations. (the + refers to 3 LPTV and an off-axis ION) In this case the AP-2870 is a clear winner for overload resistance.

What impressed me about the AP-2870 was a low pass filter on the VHF amplifier and a high pass filter on the UHF section. These would help reduce overload even when connected to an all-channel antenna on either port.

The AP-2870 actually has two FM filters, one is tunable, the other is more broadband.

 

[EscapeVelocity]

I recommended this amplifier to a fellow that wanted to use the Kosmic SuperQuad on FM Band as well. I hope it doesnt have an FM Trap.

Tower Guy, wouldnt -12 dB be piddling to avoid overload on an FM station transmitting 1 mile away using an CM4228?

 

[Don_M]

Depending on how long ago T.G. looked at the 269's circuit board, both sides may be right: It may have lacked a trap back when he opened it, but it's entirely possible that 1) W/G has since modified the circuit to include a trap and 2) the company hasn't yet changed outdated info on its Web page, Knowledge Base and instructions. A fixed trap is little more than a coil and maybe a resistor in parallel, right?

EDIT: I bought an HDP-269 ca. June 2008 and used it for maybe two hours before packing it up and storing it for future use. It made absolutely no difference in DTV "signal levels" as reported by our TV's onboard meter (yet another confirmation of highdefjeff's observation that signal quality is far more important than brute signal strength). I know it works because it did noticeably improve the video from a couple of weak analog LP stations. I'll try to take a look-see inside mine as well.

 

[Tower Guy]

Depending on how long ago T.G. looked at the 269's circuit board, both sides may be right:

I've attached a picture of the innards of a brand new HDP-269 that I received this week. The circuit board is copyright 2000. The picture taken by my Blackberry isn't the best, but here's what I see.

The large inductor to the left is a part of a three element T-network high pass filter. It would seem to have a cut-off below channel 2, but it may be a self-resonant trap for the FM band.

The small inductor to the right is in parallel with one of the chip caps making a bandpass or matching network into the amplifying device. I don't see how it could attenuate FM and still pass the full TV band. Perhaps it's like the 7777 which filters the high end of FM more than the low end.

FMfool calculates the signal from my nearby FM station at -10.1 dBm.

For those contemplating running the preamp on their own power supply, the three terminal voltage regulator is a 78M08.

 

[Don_M]

I've attached a picture of the innards of a brand new HDP-269 that I received this week.

It's appreciated. I was unable to open mine: The diameter of those molded plastic wells surrounding the F-connectors is too small to allow use of a standard deep socket for nut removal.

 

[Piggie]

Tower Guy, wouldnt -12 dB be piddling to avoid overload on an FM station transmitting 1 mile away using an CM4228?

This was the first thing that hit my mind. -12 db is not a lot of FM rejection.

 

[Piggie]

It's appreciated. I was unable to open mine: The diameter of those molded plastic wells surrounding the F-connectors is too small to allow use of a standard deep socket for nut removal.

Same thing happened to me. I easily got the bottom off but not the nuts on the F-Connectors.

But let presume it does have a -12 db filter (and as Tower guy says it may not be flat at all across the band to allow use on ch6).

If one is in a strong FM field, the best thing is probably the AP-2870 and a HLSJ both, well if you are using separate antennas. Or the AP8700, which lets you according to the instructions to leave the broad trap in and tune the variable to an offending station. Thing is these days, without test equipment how can even someone like me tune an FM trap? I could hook it to an FM radio and see if I could see a level change, but that is not as good as the analog days of watching the herringbone disappear.

 

[Tower Guy]

Thing is these days, without test equipment how can even someone like me tune an FM trap? I could hook it to an FM radio and see if I could see a level change, but that is not as good as the analog days of watching the herringbone disappear.

I have a stereo receiver with a signal strength meter. I connect the TV antenna to the FM receiver, tune to 98.3, null the signal meter, and reconnect the TV antenna to the TV set.

 

[Piggie]

I have a stereo receiver with a signal strength meter. I connect the TV antenna to the FM receiver, tune to 98.3, null the signal meter, and reconnect the TV antenna to the TV set.

Well that is what I eluded to doing in my post and glad to know it works.

There is always a way to do things. I have fixed things with just an ohm meter, that even one of my fav telephone guys on telco forum, say he only needs his butt set.

It's harder these days to do a lot of troubleshooting with a multimeter, but I didn't have a scope for a long long time. Mine is so old now I doubt it will turn on, as there is little I fix anymore at that level.

Good one!

 

[Tower Guy]

I opened up a brand new HDP-269 that I received this week.

I don't see how it could attenuate FM and still pass the full TV band. Perhaps it's like the 7777 which filters the high end of FM more than the low end.

Yesterday I had the HDP-269 connected to a spectrum analyzer while using an HD7082P antenna. There was indeed a dropoff on the signal levels on the upper half of the FM band.

So it seems that the FM trap in the HDP-269 might be helpful above about 100 MHz.

 

[EscapeVelocity]

Thanks Tower Guy. Good to know.

 

[Piggie]

Yesterday I had the HDP-269 connected to a spectrum analyzer while using an HD7082P antenna. There was indeed a dropoff on the signal levels on the upper half of the FM band.

So it seems that the FM trap in the HDP-269 might be helpful above about 100 MHz.

Did you get a chance to see the db drop? Was there any attenuation down to say 96 MHz or so? I guess you did it with OTA signals?

Most stand alone FM traps will come with a warning not to use them if you have a channel 6. There just isn't any easy way to build a brick wall slope on a filter with a few analog parts (RCL networks).

So I don't see how they could really clip much of the lower end of the FM band and be able to say the amp worked on Ch 6.

Then they would have to post a warning. Do not use this amp if you have a ch6.

So it's not a fault but about the best that is possible with a simple filter network. I would consider it a plus in such a same inexpensive amp. The tolerance to strong signals alone will save it in a lot of cases from IMD.

I would bet if you did the same thing on the other amps you would find the same thing, be it Channel Master or Winegard.

However would would be very interesting to do is hook up one of the other Winegard amps. Test it with FM trap out (comes from factory with the tunable part set above the band). Then turn the FM trap on.

The one thing the other Winegards do have is you can turn the fixed wideband trap on or off, plus there is a tunable trap to kill on station if needed. This way you could null something below 100 MHz. Or this is what I presume not having a way to check 2870.