Hi TT'rs, The circuit consists of mosfet/zener/resist series-par, thus
comprehensive in design. I'm glad to provide a photo of the circuit to
anybody seriously interested. Moreover, check out the specs on this one....
if it suits your application, fine (I'll send a copy of the PP catalog page
specs). PPHaser engineers are open to ham call inq's...ask them if their
spec "Multi-strike industrial use" means that this model could be subject to
degradation of the circuit due to transients (let alone the spec'd 36,000
amps IEEE 8/20 waveform based on ANSI C62.1).... another reason not to use
gas tube components. tel: 775 782 2511
Also, read Jim Lux's comments, makes several pertinent points.
I would not recommend gas tube types for the applications that this
unit is designed for.
Lastly, the rated bandwidth IS limited (as all are)...... on this one,
> 30 MHz, not bad in my book .
Lots of folks have issues with PPHaser pricing, but in my case, I receive
calls for insurance estimates after equipment is destroyed (not to mention
my friends house a total loss, and his dog dead). They always THEN buy
PPHaser.
73, Steve K1PEK
----- Original Message -----
From: "jimlux" <jimlux@earthlink.net>
To: "Steve Davis -Davis RF Co." <sdavis@davisrf.com>
Cc: <towertalk@contesting.com>
Sent: Saturday, March 14, 2009 11:12 AM
Subject: Re: [TowerTalk] For Sale: PolyPhaser IS-3T1 12 Cond in line
protector
gas tubes are nice, but if you're protecting something that has a low
damage threshold (like the inputs to most ICs), they're not the right
technology.
Something like a gas tube (to limit the max voltage to 50-100V, or
whatever), followed by a resistor (to limit current) and suitable low
capacitance diode clamps (to limit to the supply voltages) might work
better. Hopefully, that's what you're getting with a more expensive
transient protection device.
Fast data is a real challenge, because the C of the diodes limits the
bandwidth. Choosing a different driver/receiver chip in the device to
be protected can help (because an onchip clamp is lower C than an
external devie) "" (Jim Lux)
> Steve Davis -Davis RF Co. wrote:
>> 12 conductor protection, T1, data line protector, multi strike, 36,000
>> Amps. RS232/422. 6 twisted pair (or single conductors up to 12
>> conductors). Cast alum enclosure and all hardware SS. Surface mount
>> right angle brackets (4). Specs, picture and drawing:
>> http://www.polyphaser.com/productdetail.aspx?item=IS-3T1
>> Excellent condition. Original price:
>> $ 343.00 . Selling now: $ 195.00 plus shipping, insur, tracking.
>> This is from my personal ham equipment and I will guaranty it works.
>> Contact me off TT please.
>> 73, Steve, K1PEK
>
> Something to be aware of when using such devices (not directed at Steve
> here, but because I happen to be writing up something on these for another
> reason, and this reminded me of it)
>
> There's 4 basic schemes used for protection inside this kind of box
> (oddly, PP doesn't say which in their datasheet, for this particular
> device).. a gas tube, a back to back zener diode, a MOV, or a series L,
> shunt C sort of arrangement.
>
> The MOV style wears out. Everytime a transient comes down the line, the
> MOV dies a little bit. (that's what leads to those plug strip fires)
>
> All of the data protectors have a voltage rating, which can bite you if
> you're not careful. Hooking a 24VAC relay control on a 7V telecom
> protector will probably cook the protector (Yes.. I should have found the
> datasheet before hooking it up.) Watch out for RMS vs Peak voltage too,
> especialy if you're using a device that is usually for DC applications
> (telecom)
>
> The PP IS series has been replaced by the PP IX series. I don't know all
> the differences, but the IX (for some part numbers) is UL listed, so if
> you're worried about NEC compliance, check first. None of the usual ham
> coax devices from PP is UL listed, so they can't serve as your "listed
> antenna discharge unit" for instance.
>
> Jim, W6RMK
>
>
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