Ranger Radio
 

On a sunny day (Sat, 1 Oct 2005 21:06:27 +0100) it happened "The Magnum"
wrote in
:

Lol yea lots of things to push. I would like the 2970 next but would need to
sell a few other things first. Are these variable wattage and what, if they
are, do they start from? Id hate to upset the neighbours with TVI :o)
OK, I designed and build a new Watt meter today, thsi is the BIGGEST watt
meter you can imagine, once got this thing from a lot of stuff that was to be
thrown away.
What I actually do is a peak detection of the RF output at the antenna,
and then used the calculator and dummy load a lot...
Calibrated with comparing with an other known set, diguital meter and scope,
should be within 5% or so...
Because this meter had a different scale I wrote the new values in it
(it is so big hehe).
Here is what I have measured:
FM
RF gain Watts
minimum 2W
button pointing left 10W
button pointing up 27.5W
button pointing right 30W
maximum 35W

AM is the same, is SSB with mike gain to max and blowing in the mike
and RF gain to max: 144 or more watt (end meter scale).

So, I think with 2W minimum on FM and AM you will be fine.

Ranger Radio
 

"Jan Panteltje" wrote in message
news:1128538994.da8d95c0a88d0f0a09cc6e1b05a108f6@t eranews...
On a sunny day (Sat, 1 Oct 2005 21:06:27 +0100) it happened "The Magnum"
wrote in
:

Lol yea lots of things to push. I would like the 2970 next but would need
to
sell a few other things first. Are these variable wattage and what, if
they
are, do they start from? Id hate to upset the neighbours with TVI :o)
OK, I designed and build a new Watt meter today, thsi is the BIGGEST watt
meter you can imagine, once got this thing from a lot of stuff that was to
be
thrown away.
What I actually do is a peak detection of the RF output at the antenna,
and then used the calculator and dummy load a lot...
Calibrated with comparing with an other known set, diguital meter and
scope,
should be within 5% or so...
Because this meter had a different scale I wrote the new values in it
(it is so big hehe).
Here is what I have measured:
FM
RF gain Watts
minimum 2W
button pointing left 10W
button pointing up 27.5W
button pointing right 30W
maximum 35W

AM is the same, is SSB with mike gain to max and blowing in the mike
and RF gain to max: 144 or more watt (end meter scale).

So, I think with 2W minimum on FM and AM you will be fine.

Thanks for your detailed answer. Its nice to know people are still prepaired
to take the time to help. I might buy one of these then if i can find one
cheap enough (not too cheap as to be a duff one though) as im in no real
rush being as i already have the 2950.
Best regards,
Graham

Ranger Radio
 

"The Magnum" wrote in message
...

"Jan Panteltje" wrote in message
news:1128538994.da8d95c0a88d0f0a09cc6e1b05a108f6@t eranews...
On a sunny day (Sat, 1 Oct 2005 21:06:27 +0100) it happened "The Magnum"
wrote in
:

Lol yea lots of things to push. I would like the 2970 next but would
need
to
sell a few other things first. Are these variable wattage and what, if
they
are, do they start from? Id hate to upset the neighbours with TVI :o)
OK, I designed and build a new Watt meter today, thsi is the BIGGEST
watt
meter you can imagine, once got this thing from a lot of stuff that was
to
be
thrown away.
What I actually do is a peak detection of the RF output at the antenna,
and then used the calculator and dummy load a lot...
Calibrated with comparing with an other known set, diguital meter and
scope,
should be within 5% or so...
Because this meter had a different scale I wrote the new values in it
(it is so big hehe).
Here is what I have measured:
FM
RF gain Watts
minimum 2W
button pointing left 10W
button pointing up 27.5W
button pointing right 30W
maximum 35W

AM is the same, is SSB with mike gain to max and blowing in the mike
and RF gain to max: 144 or more watt (end meter scale).

So, I think with 2W minimum on FM and AM you will be fine.

Thanks for your detailed answer. Its nice to know people are still
prepaired
to take the time to help. I might buy one of these then if i can find one
cheap enough (not too cheap as to be a duff one though) as im in no real
rush being as i already have the 2950.
Best regards,
Graham

I forgot to ask, do you think the 10-14A PSU i have will be strong enough to
power this (when on full power) or should i think about getting a 20A one?

Ranger Radio
 

On a sunny day (Thu, 6 Oct 2005 16:11:20 +0100) it happened "The Magnum"
wrote in
:

I forgot to ask, do you think the 10-14A PSU i have will be strong enough to
power this (when on full power) or should i think about getting a 20A one?
I have used an 8A computer AT supply, it works on that, used it with an ampere
meter, kept the current below 8A... that is RF power knob a bit before middle
position.
Now it is on a 12V 12Ah gel battery, and charging from an AC adaptor I
modified to make 13.56 volt (and it has current limit).
So, the battery is always charging, but with about 1 A maximum.
The battery is made by 'Enduring' (China).
I have not run out of battery power yet....
In theory it give should less then an hour at full power,
but in SSB you are on average much lower then that, only the peak current
counts.
Your 14A PSU will not be able to handle the SSB peak of 18A, at full RF
power.
Although my charger is only 1A, the battery will do 18 A peak no problem.

These links are about SSB average power, quoting an average of about 14dB:
http://www.ac6rm.net/mailarchive/htm.../msg01197.html

http://www.ac6rm.net/mailarchive/htm.../msg00596.html

So, maybe 1/8 the power on average, so 12/18 * 8 = 5.3 hours speech at
150W PEP in SSB on a battery charge...

In FM much less time, given half the time speaking at 12A perhaps 2 hours...

So, the gist is, you can get away in SSB with a small power supply and a good
small battery.
That will give you isolated hum free operation too, and you are still OK
if power fails, say in case of flooding or some disaster.
That is why I did it this way (and it was cheaper then a new 18A PSU too).

It is your choice, you can always use reduced power.