EXACTLY!
Funny, we have the same thing here now in my club.
Our repeater is on top of a mountain near my QTH, inside of a little aluminum
box.
No heat in the winter, no air condx in the summer.
It must endure enormous temperature swings.
There are so many wonderful new DMR repeaters available for a song and a dance,
but they all have a computer and the "ONLY" problem the German importer of
these Chinese repeaters has seen is the need to power cycle the repeater after
a thunder storm.
We have no access to our repeater from November until March, due to snow.
Even when the wx is good, only one man in our club has legal access to the
premises.
So in cases like these, you try to build and deploy the most reliable
technology on the planet.
Well that is what I like to do in nearly all cases! KEEP IT SIMPLE and keep it
working.
Unfortunately the modern ham thinks everything must be auto-this and auto-that
and doesn't understand the implications of deploying that type of technology.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Clayton
Brantley via TenTec
Sent: Friday, February 27, 2015 8:45 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] 252Mo supply
Rick: I doubt it would blow up that quick! HI. We used a toroid transformer
that was Xerox surplus.They had two types and ours were the 14 volt versions.
There was a 24 volt version too. The powertransistors were from Motorola and
the 'MJxxxx" series. The biggest parameter was to insure the restingvoltage
drop across the transistor was a narrow as possible. You know the relationship
of current drawand voltage equals HEAT and lots of it if the drop across the
transistor is too high. We tried to keep thedrop below 5 volts if possible.
Royal, K4EAJ (SK), was very adamant that we used the KISS principalbecause the
trip up the hill was only available in the summer. His repeaters worked for
several yearswithout too may problems. He built a remote control that would
link,enable tone, and quite a few otherthings.
73 and CULClayton N4EV
From: Rick - DJ0IP / NJ0IP <Rick@DJ0IP.de>
To: 'Discussion of Ten-Tec Equipment' <tentec@contesting.com>
Sent: Friday, February 27, 2015 5:12 AM
Subject: Re: [TenTec] 252Mo supply
Sounds very good, clayton.
Also very simple circuit.
Survival on a mountaintop is really quite a feat.
Mine only saw room temperature for 35 years.
Back in 1980 when I built mine, I had just bought a house and had very empty
pockets.
I was looking for the cheapest possible solution, and simplest, (of course).
My bridge rectifier was out of a car alternator circuit.
I bought two of them for just a couple of bucks each in some electronics shop.
Still have the second one as a spare.
I have spare transistors, but no spare electrolyte capacitors. However they
shouldn't be difficult to find replacements for, should one ever fail.
Now that I've bragged about my power supply so much, it will probably blow up
in my face next time I turn it on (hi).
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Clayton
Brantley via TenTec
Sent: Friday, February 27, 2015 12:23 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] 252Mo supply
Rick: Looked at your homebrew PS and it's almost the same as the one I have
here. I use a 30 ampdarlington pass transistor and the 7815 drives the base of
the pass transistor. The "crowbar" is simply a 10 watt 15 volt zener diode
that will become a dead short and blow a fuse at the input of the
passtransistor. The darlington device has a 1.4 volt drop from base to
emitter, thus the output voltage is13.6 volts, which is just under a full
charged 12 volt battery (13.8 volts).
When the 78xx devices fault, the output goes to zero. That is what I like
about them. We tested theproto-type for 24 hours in a oven set to 120 degrees
F and then for another 24 hours in a freezer.This was to insure operations as a
repeater power supply. These power supplies ran for several yearson a mountain
top in East Tennessee at the K4EAJ repeaters without the first fault.
I like you design too. Should be very dependable.
Clayton N4EV
From: Rick - DJ0IP / NJ0IP <Rick@DJ0IP.de>
To: 'Discussion of Ten-Tec Equipment' <tentec@contesting.com>
Sent: Thursday, February 26, 2015 5:33 PM
Subject: Re: [TenTec] 252Mo supply
I'm always amazed to see people running power supplies without a crowbar.
This is about as dangerous as driving on "slicks" in a snow storm and not
wearing your seat belt.
A crowbar is a dirt simple circuit to homebrew and add to any power supply.
It will cost less than $10 and can save hundreds of dollars in potential damage
to our radios.
When I got my first Omni in 1979, I couldn't afford the matching P.S. so I
home-brewed one.
Here is a brief description:
http://www.dj0ip.de/ten-tec-stuff/homebrew-p-s/
Not shown in the schematic is the Circuit Breaker / Switch plus power indicator
lamp on the AC input side.
I just uploaded this tonight.
I can make some pictures and upload them later.
This power supply is 35 years old and still in operation today.
NO EXCUSES, PEOPLE! If you do not have a crowbar on your power supply, add one!
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Douglas via
TenTec
Sent: Thursday, February 26, 2015 10:13 PM
To: tentec@contesting.com
Subject: Re: [TenTec] 252Mo supply
I'd not use a 2N3055 substitute for a pass transistor in the 252M supply.
The 2N3055 only has a collector current rating of 15 amps. There are better
subs out there with higher ratings. I believe the original transistor used in
these single pass transistor supplies was a 2N5301. It's collector current
rating is 30 amps.
It's available here:
http://www.mouser.com/ProductDetail/Central-Semiconductor/2N5301/?qs=Ypxpq5e
NvNU0NwYSSi8qxw%3D%3D
The 252M supply can be adjusted fine for 12.1 V.
Perhaps you were warned against using this supply because it has no built in
over-voltage protection. When that pass transistor shorts, the output can rise
to something like 30 volts, really doing a job on your transceiver.
Ten-Tec originally sold an optional over-voltage protection crowbar circuit in
a small external box. I've one in use with my 252M supply.
The 252 M(O) supplies do have a crowbar circuit for over CURRENT protection,
the so-called electronic circuit breaker.
73,
Doug/WA1TUT
Date: Thu, 26 Feb 2015 10:37:14 -0600
From: Chris Howard w0ep <w0ep@w0ep.us>
To: tentec@contesting.com
Subject: Re: [TenTec] 252mo supply
Message-ID: <54EF4BBA.5050002@w0ep.us>
Content-Type: text/plain; charset=windows-1252
My bridge rectifier seemed to be ok.
But the big pass transistor was reading dead short between collector and base.
I replaced that with another 2n3055 that I had on hand.
That seems to have done the trick.
Chris
On 2/9/2015 1:24 PM, Chris Howard w0ep wrote:
>
> Thank you Ralph!
>
> I hooked the Omni up to a Pyramid linear supply that I have here. I
> can run up to about 10 watts and then the voltage sags enough to cause
> the frequency to change. So, I am ok if I stick to lower power.
>
> I'm going to dive into the 252mo supply and see what is what.
>
> Do you think it would be better to get a switching-type supply? Should
> I be worried about noise on the power line?
>
> Chris
>
>
> On 2/8/2015 9:22 PM, Ralph Arnold wrote:
>> I had the same problem with my OMNI D the PS is bad mine blew the
>> Bridge Rectifer and the 3055 Voltage Regulators were leaky I also
>> replaced the electrolytic cap it was old Now it works like a champ
>> Oh BTW check output with a known good DVM and I also Scoped PS for
>> clean power.(no 60 cy ripple. Im an old USN Aviation Tech KD8BTQ
>> ---Ralph
>>
>> On Sun, Feb 8, 2015 at 11:41 PM, Chris Howard w0ep <w0ep@w0ep.us> wrote:
>>
>>>
>>> I was tuning up the antenna with my Omni-D yesterday afternoon and
>>> everything went completely dead.
>>> I was not high on SWR and not turned up to maximum power.
>>>
>>> Turning things off and on I was able to get the power supply meter
>>> light to come on, but nothing on the rig.
>>>
>>> I have the light in my SWR meter hooked up to the supply also, and
>>> that is not working. I think the supply has problems.
>>>
>>> -- later --
>>>
>>> I jumper the "SW" ports of the connector, plugged in in the supply
>>> and fired it up. Sure enough, the supply lights up but no output.
>>>
>>> Any advice before I dive in?
>>>
>>> Chris
>>> w0ep
>>>
>>>
>>>
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>
>> _______________________________________________
>> TenTec mailing list
>> TenTec@contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
>
------------------------------
Message: 11
Date: Thu, 26 Feb 2015 12:19:24 -0500
From: "Al Sirois" <alsirois@roadrunner.com>
To: <tentec@contesting.com>
Subject: Re: [TenTec] 252mo supply
Message-ID: <95D02EADB0D14D3C9E8385CE62176E83@officepc>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Thursday noontime, guys:
My discussions with Paul at T-T some time ago, told me NOT to use the 252mo
supply with the Jupiter or Scout. He said it doesn't keep the voltage about
12.1 VDC.
The 252om is OK for the OMNI-A, B, C, D.
Al Sirois/N1MHC
==============
-----Original Message-----
From: Chris Howard w0ep
Sent: Thursday, February 26, 2015 11:37 AM
To: tentec@contesting.com
Subject: Re: [TenTec] 252mo supply
My bridge rectifier seemed to be ok.
But the big pass transistor was reading dead short between collector and base.
I replaced that with another 2n3055 that I had on hand.
That seems to have done the trick.
Chris
On 2/9/2015 1:24 PM, Chris Howard w0ep wrote:
>
> Thank you Ralph!
>
> I hooked the Omni up to a Pyramid linear supply that I have here. I
> can run up to about 10 watts and then the voltage sags enough to cause
> the frequency to change. So, I am ok if I stick to lower power.
>
> I'm going to dive into the 252mo supply and see what is what.
>
> Do you think it would be better to get a switching-type supply? Should
> I be worried about noise on the power line?
>
> Chris
>
>
> On 2/8/2015 9:22 PM, Ralph Arnold wrote:
>> I had the same problem with my OMNI D the PS is bad mine blew the
>> Bridge Rectifer and the 3055 Voltage Regulators were leaky I also
>> replaced the electrolytic cap it was old Now it works like a champ
>> Oh BTW check output with a known good DVM and I also Scoped PS for
>> clean power.(no 60 cy ripple. Im an old USN Aviation Tech KD8BTQ
>> ---Ralph
>>
>> On Sun, Feb 8, 2015 at 11:41 PM, Chris Howard w0ep <w0ep@w0ep.us> wrote:
>>
>>>
>>> I was tuning up the antenna with my Omni-D yesterday afternoon and
>>> everything went completely dead.
>>> I was not high on SWR and not turned up to maximum power.
>>>
>>> Turning things off and on I was able to get the power supply meter
>>> light to come on, but nothing on the rig.
>>>
>>> I have the light in my SWR meter hooked up to the supply also, and
>>> that is not working. I think the supply has problems.
>>>
>>> -- later --
>>>
>>> I jumper the "SW" ports of the connector, plugged in in the supply
>>> and fired it up. Sure enough, the supply lights up but no output.
>>>
>>> Any advice before I dive in?
>>>
>>> Chris
>>> w0ep
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