Filters first, Then Setting up Ancient Modulation, Then troubleshooting a SWR problem;
Here is my favorite filter outlay using **InRad Filters
---2nd, High IF, 8.3 MHz slots---
** 2.8 KHz @ 2.4 position
2.4 KHz OEM @ 2.0 position
** 6.0 KHz @ 500 position
500 Hertz OEM @ 250 position
---3rd, Lo IF, 455 KHz slots---
** 2.8 KHz @ 2.4 position
2.4 KHz OEM@ 2.0 position
** 10.0 KHz @ 500 position
** 400 Hertz @ 250 position
***See Note Below on Changing one more filter
Why I use tandem 2.8 KHz. filters for my favorite SSB bandwidth parameter, follows below. Note; I only purchased the 1000 MP after learning that these 2800 Hz filters were available for this transceiver as voice is my favorite mode.
Human voice studies show that using a total voice bandwidth such as 3 KHz , which on SSB with a 200 hertz carrier shift would be a working 6 db down bandwidth of 200-3200 Hertz ), would allow transmitting a small amount of syllabance and vowel constants in the human voice, creating higher intelligibility and producing less fatigue, at the cost of only 500 Hertz more channel bandwidth than a 2.4 KHz bandwidth. The fatigue is reduced as the listeners brain doesn't have to fill in the missing parts. Actually less total bandwidth will be transmitted using two InRad 2.8 KHz filters with the increased shape factor of 16 crystal lattice poles in tandem, than many other transceivers using only a single 2.4 KHz , 8 pole filter. A pair of these 2.8 KHz filters with medium strength signals sound as pleasant listening, as the Good Olde Collins 3 KHz filter days. Transmitting and receiving the lows below 300 hertz is necessary to hear the vowel constants to know you are operating on the same RF frequency as the other persons. Transmitting and receiving the highs of syllabance above 2800 hertz reduces the need for phonetics as you can actually hear the difference between a F and Ssss and many other words more easily, also reducing the fatigue created in the listeners brain as it doesn't have to guess the missing word parts. To test your transmitted syllabance signal level , Use your built in audio oscillator and simply hiss ( open lips slightly and hiss gently, like a air leak) near your mike ( not into it ) while watching a peak reading wattmeter. The wattmeter should read as high, as it does with low and mid pitch humming. And yes; unfortunately enjoying more of the Lord's designed human voice requires more bandwidth entering into the population vs. bandwidth debates.
*** Filter notes from my 1000 mp posts, 01 Aug
2000; When
receiving AM the shape factor for the Synchronous detector receiver
is determined exclusively by CF2001, a Murata CFW455G, 6 pole ceramic filter.
This filter is 9 KHz at 6 Db down, widening to 20 KHz only 40 Db down
selectable in and out but hard wired in without options to add any other tandem,
steeper skirt filters before or after it.
Mean while the internal 455 KHz 6 KHz Stock
Filter, which is selectable at the front panel (labeled
"6.0K") but also hard wired in, is CF2002, a Murata CFWHT, 6
pole ceramic filter, which is 6 KHz at Six Db down, widening to 18 KHz only 40
Db down. I believe Yaesu should have used at minimum, cheap 11 pole filters in
the 1000MP. Many of us purchase the Yaesu PN# CF2001 for the IF UNIT, FM
receiver a Murata CFW455G a 9 KHz filter and replace the CF2002 a Murata
CFW455HT 6.0 KHz filter for better syllabance bandwidth when listening and
transmitting AM. My page on balanced modulator changes with filter
comments at bottom <<< here >>>
also
muRata Filters
More filter notes from my 1000 mp posts; The
internal 455 KHz 6 KHz Stock Filter used in many modes, and selectable at the
front panel is CF2002, a Murata CFWHT, 6 pole ceramic filter, which is 6 KHz at
Six Db down, widening to 18 KHz only 40 Db down. This is quite a poor shape
factor. This physically is a little 11 X 7 mm rectangular filter and difficult to replace with
a better shape factor, much longer one.
Click Here for my article on changing this filter. You are starting properly with a good
shape factor at the hi ( 8.3 MHz ) IF first. Cascading a better quality low IF
filter for rough AM conditions is a expensive option, which I will add later.
With only one default carrier shift option for both 2.8 and 2.4 SSB filters, I
believe I have located the SSB filters properly. Also the AM filters will not
function in any 250 position so I must use the 250 position for my two CW
filters and the remaining 500 position for AM filters. The DSP audio filter will
further reduce the CW shape below 400 Hertz nicely. When moving the OEM ( Yaesu
) filters, they did not have ground pins at each end and after mounting them on
the InRad adapter board, I had to ground the case mounting tabs to the InRad
adaptor board ground plane with some braid. Also when mounting the InRad filters
at the OEM soldered in locations , as InRad has ground pins at each end, I had
to heat some solid 22 gauge wire and run through the existing PC board holes to
open them up. No drilling is necessary. InRad will sell you the small plug in PC
boards which hold the filters for $10 apiece. Also, don't forget to consider
using old 455 KHz
filters from CB and Two way business band radios. Nice shape factors in old
Motorola tube type narrow band, business band transceivers.
No IALC might be better on SSB Transmit, it certainly is on
AM; notes from my 1000 mp posts; The
other day, after talking to Gary, WA1OXT, who mentioned that on AM he ran no
ALC with his Transceiver. Therefore I set out to examine my FT-1000MP Rev
5 up. I first set the RF power on front panel fully clockwise. I was tinkering around on SSB and rotated the internal
IALC Pot fully Clock
Wise ( reducing the RF Final IP current limiting ). Pot was factory set about 20% from Fully
clockwise. Yep sure enough there was less off channel crud ( very
noticeably ) 5 and 6 KHz down the band when transmitting LSB, even when cranking
up the Mic gain a extra amount. Before I changed the IALC pot setting I had
rotated the P.MAX pot ( near the 10 and 50 watt pots ) clockwise and found that
the off frequency crud level rose quickly when going above a CW level of 120
watts, there fore I set the level to 110 watts. Now after reducing the
IALC I
moved this P.MAX pot again finding the CW carrier was about 135 Watts out, (
much higher ) before the off frequency crud level would start to rise when
transmitting SSB. I left it set to about 125 watts out on CW for a little reserve.
Notice, that here we are using the Normal ALC circuit
to limit the max RF without also current limiting the RF finals MAX Drain Current.
Next the pot labeled " AM " is set for about 15 watts of quiescent carrier out. My
conclusion is that the IALC circuit introduces a lot of distortion ( off channel
shot noise ) when transmitting SSB, actually making things much worse than
better off channel. I have seen this in a few other solid state transmitters
before. Usually the poorly designed ALC circuits in some cases simply needed
an added, source follower with more decay release filtering, with a small resistor and large cap in series across the
new low impedance ALC
buss. I was barefoot when doing this. My Spectrum analyzer was a old Drake R4C
with a S9 signal into it and an Commercial Polarad model DU1A Spectrum Analyzer.
I have a high composite voice with a fundamental of 75 Hertz and full range Mic.
When testing don't use a few tones or a string bean ( very narrow ) voice or
mike. And its hard
to beat using your ears, with a external SSB receiver with RF gain off and lots
of audio gain. Its very hard to see off channel shot noise on a fast persistency
scope, but very
easy to hear.
Afterwards my old Heath Kit SB-220 ( pair of 3-500Z's ) also likes the extra
drive when tuning up for max CW carrier out and then over coupling by turning
the antenna loading control clockwise dropping output power about 8 % for better
grounded grid linearity. I don't use any external ALC back to the exciter, only over coupling
at the Final. Yes its a Yaesu 1000MP, dated late 2000. I expect to take the time
when ready for winter to fix this design problem. This crud we all listen to on
the side of many stations doesn't seem to be included in any reviews of new
transmitters. Just putting two tones into a transmitter and displaying the IMD
results is too easy a review. Personally when I talk to someone, I don't whistle
two tones simultaneously. I remember after my 1958 DX-100 days ( Hi Earl, K6SE, W8DGP )
that The first well working ALC I experienced was in the Heath, Triple action
level controlled SB-100, where you could really tromp the mike gain and sound
good on and off channel. Also remember how clean the Central Electronics phasing
rigs sounded off channel without any ALC? If we all paid as much attention to
ALC as we do to our Receiver AGC circuits it might be a better World.
The $10 InRad AGC Modification I find absolutely necessary when using any mode during lightning storm static interference. During these short duration, high strength spikes we are forced to use the fast AGC setting so the receiver will recover quickly enough as not to miss the first word or character of any signal weaker than the static. With the original poor design in the fast AGC setting ,the signal modulation appears on the internal AGC buss causing unnecessary fatiguing, distortion which is unacceptable poor design.
Adjusting the FT-1000 MP or most any 100 watt output SSB transceiver for AM transmission. IE. Is your voice lopsided ? Yes, if you are a Male.
If you had a symmetrical voice, which a female or a very high pitched male have , 100% modulation of a 25 watt carrier would produce 100 watts PEP. Deep sounding males ( thanks to their larynx ) can easily be asymmetrical ( lopsided ) up to 150% which would mean that a 12.5 watt carrier would produce 100 watts PEP. I run a carrier level of 10 to 15 watts on AM for little distortion. I can push it to about 20 watts, but other fussy people notice the distortion. I also have audio phase reversal switches on my microphones. With a Oscilloscope you can quickly get your audio phase properly set for about a negative going 95 % and well over a positive going 100% ( up to 145% ) modulated carrier. Thus your output wave form would be identical to your audio input wave form. The last thing we want to do is over modulate with negative going ( over - 100% ) modulation as substantial adjacent channel noise is produced when the low level mixer is cutoff (carrier cutoff). Therefore with a MP ( 100 PEP) I recommend 15 watts and a Mark 5 ( 200 PEP ) 30 watts with audio phase set for more positive going than negative going modulation. You can feed your mike directly into a scope to check your asymmetry. But put scope on RF for proper phase setting as even some factory mikes are backwards. In SSB there is no need for any phase check.
With no modulation .. RF power
level on front panel fully clockwise. AM position. Set internal carrier level
pot to 15 watts output for a MP... 30 watts for a Mark 5. These are
the maximum carrier amounts for an asymmetrical (male) voice !
The 15 watts applies to any 100 watt PEP output transmitter. Now when you
modulate, crank up the Mike gain watching a watt meter on
Average ( not peak ) Power, until the carrier power only occasionally kicks
downward. This downward kick is your carrier being cutoff, resulting in
distortion. No downward deflection would be distortion free. Without compression
or peak limiting a little downward would be acceptable to keep the average up.
If you monitor yourself with good headphones ( I like Sony CD10's about $20) ,
as you bring up the Mike gain you should hear the distortion as you start to
kick your external average watt meter downward. When set properly with little
average downward, now observe the Internal PO (power out) meter. You should see
your 15 watts of carrier and as you modulate your peaks of 100 watts or slightly
higher should show momentarily. Although your carrier power is only 15 watts
your PEP will be 100 watts or slightly higher. Yaesu automatically
disables Processing in AM. By the manual I set my metering menu hang
time to two seconds (2000 ms) for all functions. For excellent modulation
reports I use a $30 dollar Radio Shack Mike #34069 with a Radio Shack wind sock
plugged into the RCA Phone Patch input on the rear and the FT-1000 MP's internal
TX EQ Menu 4-4 set to #4. And then to roll off some lows on SSB ( as
my voice is too bassy ) : Menu 7-7 SSb-t at 150-3100 or 200-3100 .
Repairing your own lightning blown FT-1000 MP
One memorial day morning, I turned on my Yaesu ft-1000 MP to find I had no more than 20 watts output on any mode or band. Next, I noticed that the built in reflected SWR metering was full scale even into my dummy load. If I used my external, manual antenna tuner into a dummy load and went off one side of resonance ( 3:1 ) , I could null my reflected reading on the FT-1000 MP internal SWR meter. Oh No ! The previous evening I had forgotten to ground my 80 meter antenna system on the 120 foot tower, and there was lightning in the area.
With the above symptoms, I assumed the internal SWR bridge was kaput. Looking at the schematic's which came with the rig, I finally found the SWR bridge on a low pass filter board located near the RF output finals. I knew these finals had to be bolted to the bottom of the massive heat sink, and sure enough, I found the 4 diode SWR bridge nearby. The schematic showed the diodes as 1SS101 , and by using http://www.google.com/ ( the best search engine ) I downloaded a PDF application file, that showed the diode characteristics as Shottky Barrier type. My trusty Radio Shack Ohm meter ( 22-163 ) revealed one diode ( in circuit ) having no front to back ( 85 ohms in both directions ). The 3 good diodes read 85 Ohms back and .5 Ohms forward. I called the people at Yaesu Tuesday morning, and they suggested I double them up. This sounded a little strange, but the bottom line was " they don't seem to order a second time. " Therefore, I ordered 10 diodes ( two spare ). And when they ( part # change from 1SS101-T1 , G20902 to G2060018 ) arrived two days later, I first made up 4 diodes , with two doubled up in parallel to replace each of the original four diodes. Sucked and soldered away, I fired it up and I didn't even have to touch the null trimmer. And away I go until "The next time. " Whew ! No chance for shipping damage is a relief ! BTW: diodes are long wire, lead-out types, very easily changed !
Technical service said this SWR bridge problem has happened many times before. For the future, I also ordered a 3 tab +9 volt voltage regulator ( PN: KIA7809PI / G1092163 ) to put on the shelf, in case my Audio Output IC , shits the bed some day ( Vermont dialect ) . Time to say thanks to Vertex / Yaesu for their parts stocking and time to look into transient voltage clamps ( back to back zenier diodes ) for antenna input protection. The original 1SS101's in the SWR bridge are rated at 70 volts and 15 Mils.
Modulating the FT-1000MP Balanced Modulator Directly from your Audio Processor or Audio Equalizer.
A New Inexpensive Studio Condenser Microphone and audio processing; digital Behringer & Marshall
Remote Base controlling your Ham Gear using your Cordless telephone
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05/22/2007
"Two First Commands"
my story about meeting my maker