At 1800W an N gets barely warm on 144 MHz and a bit warmer at 400W on 432.
The combined pair of Eimac cavities at 500W gets decidely toasty on 903 (-;
These are all silver plated USA mil-spec. A similar PL-259 on 2M was
uncomfortable after a few minutes of key down which is what led to the
change.
I can imagine what the combined 150W bricks on 1296 will do but that and 903
are not exactly high activity bands.
Carl
KM1H
----- Original Message -----
From: "Sam Carpenter" <sam@owenscommunication.com>
To: <dhallam@knology.net>; <amps@contesting.com>
Sent: Tuesday, May 01, 2012 4:50 PM
Subject: Re: [Amps] every db lost re Tubes vs. Solid State
>I wish they were all N or HN or DIN Connectors. I have seen some pl259, and
> even N connectors do ugly things under load, admittedly more at higher
> frequencies. Commercially we are using DIN Connectors more and more. In
> part
> because of the Power of several combined transmitters on one line at380 &
> 700-800-900 mHz, but more for low PIM. I compromised once on a cheap PL259
> connector I had in a drawer and while tuning up an LK550 (HF) got quite a
> loud surprise. It blew the RG8 right out of the connector and made quite a
> fire ball. One of the tubes had a bad reaction to that. It was costly. I
> have noticed on the captivated pin (crimp on) N connectors, they get
> pretty
> hot with just a couple hundred watts of 800 mHz. We use some crimp on
> connectors for low power mobile, low power control stations, etc... but
> never outside and never never with high power. There is no substitute for
> a
> properly soldered and tightly installed connector that is trimmed
> properly.
> Just like getting over 500 hp in a car, things start breaking fast,
> getting
> QRO, similarly things start breaking and sometimes catching on fire. It is
> such a simple cheap thing to buy and install the best connectors for
> everything past the amp and to the antenna. I think it is a terrible place
> to compromise. I would rather do that at the low power end of things. I
> think Henry had the right output connector on the 4k Ultra. Sam N9FUT
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of David C. Hallam
> Sent: Tuesday, May 01, 2012 4:33 PM
> To: amps@contesting.com
> Subject: Re: [Amps] every db lost re Tubes vs. Solid State
>
> I realize that the investment of a proper crimping tool and dies for UHF
> is
> an investment of not insignificant proportions. But compared to the
> investment in a modern SS transceiver, it's a small price to pay to get
> the
> expensive RF to the antenna. In every comparison test I have seen,
> crimped
> connectors were equal to or better than soldered connectors.
>
> I gave up on soldering braid on PL-239's sometime ago.
>
> David
> KW4DH
>
> On 5/1/2012 4:13 PM, Manfred Mornhinweg wrote:
>>> Some years ago, I discovered a 'cure' for the problems brought to my
>>> station by cheapie connectors. They ALL went into the S***can!
>> Much the same here. And it's a real problem, because every connector I
>> can buy locally (Chile) is Chinese-made, and while the best of them
>> are satisfactory, most of the rest are junk.
>>
>> But not always is the problem attributable to a bad connector. Very
>> often it's bad installation. I don't know how it's in the USA, but
>> around here it's truly surprising how few hams know that the holes in
>> the sides of a PL-259 connector are there to solder the braid! People
>> will strip the coax, push or thread it into the PL-259, solder the
>> center conductor, and leave the braid to contact the shell by
>> proximity, telepathy, good luck, or by the never-failing (so they
>> think) spring action of the plastic jacket...
>>
>> Only the internal conductor is hot with RF, right? So it doesn't
>> matter if the braid makes no contact, right? That's what they think.
>>
>> And then there are those who have emancipated from this step. They
>> will push the coax cable into the connector, and then try to somehow
>> patch those pesky solder holes with some half-melted, pasty solder.
>> The braid inside stays untouched.
>>
>> Or those who want to do it right. They push in the cable, then heat
>> the whole connector with a torch, and flow abundant solder into those
> holes.
>> This time the braid gets properly soldered to the body. And so does
>> the center conductor. To the body, I mean.
>>
>> I have held workshops at three different radio clubs, to try teaching
>> people the correct installation of a PL-256 connector, and I have
>> found that many hams just plainly lack the ability to understand why
>> it should be that way, or the discipline to actually do all necessary
>> steps, specially tinning the connector body on the inside before
>> pushing the cable in, and tinning the braid...
>>
>> I have seen PL-259 connectors in which the braid had been unbraided,
>> twisted into two bundles like Salvador Dali's mustache, pulled through
>> the solder holes, and the two ends knotted together outside the
>> connector's body! A great, safe contact, sure! ;-)
>>
>> Oops, I'm in ironic mode today. Forgive me... Must be because it's 1st
>> of may...
>>
>> Manfred
>>
>>
>> ========================
>> Visit my hobby homepage!
>> http://ludens.cl
>> ========================
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
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