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problems with Max Pro IV+
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bhays
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Post problems with Max Pro IV+ Reply with quote
I just purchased a Max Pro IV+ and SE4+ encoded.

Units seem to be working fine from lcd, etc. I have an adequate power supply, good quality 50ohm coax and tunable 1/4 wave antenna, etc.

I plugged these units in place of a 5 watt transmitter I had previously (xxxxxx).

I am only getting less than half the range I got with the 5 watt transmitter?

Jumper is on A, power adjusted to full on lcd menu, etc.

Is it possible that I have only the 3 watt final transistor? How can I tell for sure. Do the finals ever become damaged partially, or is it all or nothing?

I have included a picture of the board below as I know you sometimes need to see that.


Wed Aug 22, 2007 7:49 am View user's profile Send private message
pcs
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How many volts on the power supply?
What frequency?

Is antenna tuned? This unit has swr protection, if swr is not good it starts to
shut power down.

Marko

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Wed Aug 22, 2007 10:15 am View user's profile Send private message Visit poster's website
bhays
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pcs wrote:
How many volts on the power supply?


Well, it's labeled 15 volts 1500ma, but when I checked the output with a meter it was 19 volts. Is that cause for concern?

pcs wrote:
What frequency?


89.9

pcs wrote:
Is antenna tuned? This unit has swr protection, if swr is not good it starts to
shut power down.

Marko


I do not have an swr meter, but it is tuned by length according to the chart provided with the antenna. I contacted the antenna mfr and they claim their tuning chart is quite accurate and I should be very close.
Wed Aug 22, 2007 12:41 pm View user's profile Send private message
pcs
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1. This power supply is rubbish. Its not even stabilized and it is not of adequate rating.

2. The power tends to be a bit lower at band edges, but no reason for concern there

3. Yes, when mounted in a standard way away from metal objects. If, however, you have
it in the attic, close to metal objects etc the tuning chart may not be correct.

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Wed Aug 22, 2007 3:34 pm View user's profile Send private message Visit poster's website
bhays
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pcs wrote:
1. This power supply is rubbish. Its not even stabilized and it is not of adequate rating.


I will obtain a 15volt 3.3amp regulated power source today. Would 1.5 amp rather than 3 be enough to reduce power below 5 watts?

pcs wrote:
2. The power tends to be a bit lower at band edges, but no reason for concern there


Surely not less than 5 watts?

pcs wrote:
3. Yes, when mounted in a standard way away from metal objects. If, however, you have
it in the attic, close to metal objects etc the tuning chart may not be correct.
[/quote]

It's on the roof mounted on a dss satellite bracket.
Wed Aug 22, 2007 3:37 pm View user's profile Send private message
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Quote:
I will obtain a 15volt 3.3amp regulated power source today. Would 1.5 amp rather than 3 be enough to reduce power below 5 watts?


You DO NOT regulate power of the transmitter by changing power rating of the power supply. Get a 3A or more power supply.

Quote:
Surely not less than 5 watts?


Of course not

Quote:
It's on the roof mounted on a dss satellite bracket.


Sounds good, a picture would say more.

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Thu Aug 23, 2007 1:19 am View user's profile Send private message Visit poster's website
bhays
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Should the red led next to the audio input be lit? It turns on after the transmitter has been on about 20 seconds. I can't find any reference in the manual as to the meaning of the led.. does it mean swr mismatch? I notice that you can hear the transmitter on a radio prior to the led coming on, but a hum is introduced when the red led lights.


A bit of background on the situation.

The reason for getting a new transmitter is that lightning struck a tree about 60' from my house where the antenna is located. When I turned the old transmitter on after the storm, it would report low impedance on the lcd and after about the third power cycle it died completely and will no longer turn on.

I replaced the coax today, (the antenna company told me it was very unlikely the antenna was damaged) and otherwise, the max pro IV+ is plugged into the same antenna/coax.

Replacing the coax had no effect, and I had to order a 3amp power supply which will not be here until Friday. It's just hard to imagine that even with a 1.5 amp power supply, I would get half the range I had with the 5 watt unit. If the power supply change does not make a difference, I am wondering if I need to send the unit to you to be checked? Do you suppose that power supply putting out 19vdc could have harmed the unit?
Thu Aug 23, 2007 3:21 am View user's profile Send private message
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1. Yes, 19V is too much, it is possible that there was damage.

2. Yes, a crappy supply like that is not even regulated, it is a complete disaster.
This means it is putting out 19V when not loaded and only God knows what it gives
out under load. It could very well be putting out 12 or less under load. Sagging voltage
can reduce your power output by a large factor.

Understanding this requires some basic knowledge of electronics. Current rating (amps) must fulfill
some minimal level with good safety margin, which is why we spec 3 amps minimum. Whether this is
3 amps, 10 amps or 10000000 amps bears no importance as the unit only "takes" as much as it needs.
Ohms law explains it, look it up.

Voltage needs to be 15V to reach full power. If the power supply is unable to supply required current
at some voltage its voltage usually starts to sag towards zero which means output power is limited.

Due to your limited understanding of these things and cheap power supply you've been using I fear
your antenna and cable could be of similar poor quality, but let's see what the new power supply
does to the situation.

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Marko - PCS Electronics
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http://www.pcs-electronics.com
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Thu Aug 23, 2007 9:41 am View user's profile Send private message Visit poster's website
bhays
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pcs wrote:
Due to your limited understanding of these things and cheap power supply you've been using I fear
your antenna and cable could be of similar poor quality, but let's see what the new power supply
does to the situation.


The power supply was supplied with the transmitter, I only use regulated supplies. But, as I had nothing higher than 12volt on hand and I knew the transmitter had already been run with this ps, I thought I could do very little additional harm until obtaining a proper supply.

the antenna is mounted on a dss bracket next to a motorola canopy 900Mhz Internet unit. This is the same 1/4 wave tunable antenna others have used with good success. The same antenna/coax worked great with the previous transmitter.



This is the package from the new coax I put up last night, the previous was RG8U



And this is the mounting. The fan runs anytime the transmitter is on



I have hopes the new power supply will correct the problems, if not, the unit may be damaged. It works fine, however, output power is just extremely low.
Fri Aug 24, 2007 2:48 am View user's profile Send private message
pcs
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Post Reply with quote
One advice, if you are going to stay in this hobby for a while invest in a nice SWR/power
meter, that way you'll know what is going on and won't need to guess based on range.

The antenna might be a bit close to the metal pole, for example, but you can't say without
swr meter. If you do get one, make sure it is not for CB.

Another must-have is a dummy load, maybe a regulated adjustable power supply (0-15V is handy).

Keep us posted here how it goes, I hope the final survived 19V

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Marko - PCS Electronics
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Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Fri Aug 24, 2007 9:32 am View user's profile Send private message Visit poster's website
bhays
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pcs wrote:

The antenna might be a bit close to the metal pole, for example, but you can't say without
swr meter. If you do get one, make sure it is not for CB.


I picked this cheap-o up on eBay for $20 just to have something. It's not here yet. I am sure it probably is for CB, but the seller said it covered the frequency range for FM as well, and I thought it would be better than nothing for now.



I want to make sure I understand the procedure for using it, is this correct?

1) insert meter inline between transmitter and antenna
2) turn switch to 'cal'
3) turn on transmitter
4) turn cal knob until swr meter is in the 'set' ranger of meter.. (should it be all the way to right or just in the red?)
6) switch meter back to swr and adjust antenna until lowest possible reading (is it safe to leave transmitter on during this?)


pcs wrote:
I hope the final survived 19V


That makes two of us... oh well, should know soon.
Fri Aug 24, 2007 11:01 am View user's profile Send private message
pcs
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Post Reply with quote
Hi!

Procedure is correct. The only problem you may experience
with CB SWR meter might be inaccurate power reading, ie it will
probably show more or less than actual power.

It may also contribute a bit to bad SWR. Still, it will give you some
general idea. You'll know whether power is less or more than with
old transmitter, for example.

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Marko - PCS Electronics
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http://www.pcs-electronics.com
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Fri Aug 24, 2007 1:26 pm View user's profile Send private message Visit poster's website
bhays
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Well, company delayed shipping my power supply. Good news is I will have swr meter and new power supply on Weds. I am going to swap out the power supply, then check out swr on the antenna. I suspect I will either be ordering a new antenna or shipping a transmitter to you for repair shortly thereafter
Sun Aug 26, 2007 2:32 am View user's profile Send private message
bhays
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Update:

Received my cheapo swr/power meter today. Hooking it up revealed a 2.5+ swr. 'Tuning' the 1/4 wave antenna had really no results. I noticed that when I touched the metal of the dss mount the antenna was mounted to, swr dropped down to almost 1:1...

So, I moved the antenna off of the dss mount over to a piece of pvc pipe about 4 feet away from the metal mount, was able to tune swr to a pretty good level then. This is my first time using a swr meter, but I have some confidence in my readings as the 1/4 wave antenna I have seemed to produce the lowest swr when adjusted to the length indicated on the tuning chart that came with it. Power meter indicates the max pro4+ is only putting out around 5 watts, although that increased somewhat when I resolved the swr mismatch.

I am hoping the 1.5 amp power supply may be the limiting factor, I will have a new power supply on Wednesday. I did hook up a meter to the power terminals on the transmitter and discovered that under any load at all (eg as soon as the transmitter kicked in) the power supply was only delivering right at 17-15 volts, not 19 as when not connected to anything. When I corrected swr and the transmitter increased output a bit, that dropped to 14...so...I am hoping the power supply is the problem.

I will know more when the other power supply arrives.
Tue Aug 28, 2007 5:11 am View user's profile Send private message
bhays
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Ok, the 3.3amp 15vdc regulated power supply arrived today. I connected it. So, current status is:

using the swr meter, I figured out that I had about 2.5 swr, moving the antenna away from the metal mount it was on solved that and I have been able to tune the swr to a flat 1:1.

The power supply is now a regulated 15vdc 3.3amp unit, checked with a meter it maintains 15vdc reliably.

Reception is much improved, about to the level of my previous 5 watt transmitter. This make sense as the power meter on my swr/power combo meter indicates the transmitter is putting out right at 5 watts.

The power jumper is on the 'A' position.

What do I have to do to get to 10-15 watt output? What am I missing. The antenna must be good, to have a 1:1 swr, correct? I have a comet antenna coming that I plan to change out, but I am not optomistic it will make a difference.

Do you think the transmitter is damaged or defective?
Thu Aug 30, 2007 3:32 am View user's profile Send private message
pcs
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Ok, we have fixed and eliminated some of your problems and can now move on.

1. Cooling. Transmitter starts to reduce power, if too hot. This is due to protection and has been
done on purpose. Have you mounted this to a metal enclosure/plate?
A small fan blowing across the board is also welcome.

2. I would try to compress the turns of L5 together a bit since you may have less than optimal
performance at band edges. This will maximize power at lower-end.

3. You can do the same with L2, L3 and L4 carefully a little bit, keep an eye on power meter and note
that fingers upset the reading.

BTW, to double the range you need to increase power at least 4x in theory and even more usually
in practical world. By going from 5 to 10W you can hope to get maybe 20-30% more range.

Marko

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Marko - PCS Electronics
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Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Thu Aug 30, 2007 12:04 pm View user's profile Send private message Visit poster's website
bhays
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Compressing the coils gained an ever so tiny bit.

If I am reading this meter correctly, it is at 5 watts of output. The meter is halfway on 10 watt range, but the markings are 20 of 100.



Any more ideas to increase output?
Thu Aug 30, 2007 1:46 pm View user's profile Send private message
pcs
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Post Reply with quote
You won't be able to use this CB meter to measure with any accuracy,
you can only use it to compare against old transmitter and figure out
whether you are now getting more or less power.

For example, I would say this is showing 1.8W more or less, which is
definitely wrong.

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Marko - PCS Electronics
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Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Thu Aug 30, 2007 1:59 pm View user's profile Send private message Visit poster's website
bhays
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The comet antenna I ordered arrived today and I installed it.



Looks like we found our culprit Applause

Still not getting the range I would really like...looks like 40 watt amp time..
Fri Aug 31, 2007 4:48 am View user's profile Send private message
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Just remember that you need 4x more power at least to double your range. Often its more like 5-6x.

40W would be a good start
150W would be nice, some amps let you regulate power down to 0-150W, this one for example:
http://www.pcs-electronics.com/150w-digital-amplifier-19inch-rack-p-664.html
You can set it to 40W for the start and later to more, if needed.

Than again 300W would be even better and lets you do the same, set to 40W and more later

Welcome to the wonderful world of broadcasting!

Marko

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Best regards,
Marko - PCS Electronics
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Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Fri Aug 31, 2007 12:16 pm View user's profile Send private message Visit poster's website
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