The IC-7800
Contents
1. CF card in the slot An unusual feature in this radio is an output jack for the S meter on the rear panel I am not sure what application this could serve but I m sure someone will find one ethernet S meter Features and functions explained Page 2 Visit Adam VA7OJ ABAOJ s IC 7800 Page for much more info Packing Even the shipping packaging of the IC 7800 is impressive a fair amount of engineering went into the box alone The box is a two piece unit The top part pulls awav after the nvlon straps are cut After the top part is pulled off the bottom piece folds open Inside the Stvrofoam inserts are form fitted and a large plastic bag encases all Pictorial directions are shown on each piece directing the owner on proper removal of the radio A large cardboard box holds all the loose parts and documents This box contains the following items a set of rack mounting handles AC power cable bags containing all the rear panel connectors needed an ISO 9000 test result sheet more on this later the user manual and vvarranty card The users manual is a very nice 4 ring plastic binder the pages inside are semi gloss heavy paper stock It is a rather thick manual but the IC 7800 is a very heavy radio The ISO 9000 certification page contains the results of the tests on the radio it accompanies Having been involved in ISO 9000 certification in my business I can tell you it is NOT easy to get and is expensive to maintain Certifi2. 2 11 OSC UNIT toMHz X1 CR 772 Swt ching relay RiL10 FTA BACAQ2Z VO controle IRATE 0003450 D A converter 091 ADSQG0BRUSO S watching neum 8911 FTR BACAO12Z REF UO 1OMH 1008m Ref signal output The spectrum scope has its ovvn stand alone DSP unit The scope is as accurate as many extremely expensive lab spectrum analyzers Resolution bandvvidth is an impressive 100 Hz One can regard the scope as a high qualitv test instrument this is another reason that the 7800 is so expensive The display itself is a color TFT with a VGA output for an external computer type monitor 2 7 SCOPE UNIT 5V RC 232C level converter 1C903 ADM202E ARN A D converter C501 AD7650AST DSP ic re TMS3200671 10GDP200 S3 mixer D4 HSB88WS 126V lins PLL IC C201 4 30 1285 1C801 LMX2306TM vco 0821 25K210 14bit DDS IC a2 8851 1820 AD9657AST E ATT os Sense S2LO 5513 3101 2009973 15 263 52 mixer 1 1 KPG2009TB oue IC14C3 D101 HSB88WS 4 4 The PA RF Power Amplifier is a 200 watt output Power MOSFET design running at 48Vdc The PA board has four stages the first two are low level IC s also MOSFET most likelv operating in class A The last two stages are Power MOSFETS running in class AB mode 2 12 PA200W BOARD Power ampli er Q401 0402 502931 Drive ampli er 0301 502916 Pre drive amplifer 0201 PD55003 RF ampifer Q101 RDO1TMUS 1
3. PA module mounted on the heat sink with scroll fan Virtually all the filters coils caps and signal paths in the 7800 are switched in and out of line by a huge number of small relays This removes the possibility of distortions introduced by the diodes use to switch filters in other radios The Digi Sel feature on this radio is a system of relay tuned pre selector circuits operated by a stand alone CPU This gives the receiver an extra level of interference protection that can be manually tuned by the user normally the system is automatic This is a handy system that can reduce or eliminate BCI Broadcast Interference The huge coils in the BPF Band Pass Filter are all relay switched This insures the lowest possible levels of signal distortions The ATU can also be used in the RX line for an extra level of pre selection Both units are shown below BPF unit Automatic preselector Two independent fully functional receivers A amp B below is the RX PLL boards for both 2 9 RXPLL A BOARD 0621 45 6868 5 DOS IC 3rd LO IC651 SC 1287 2rd IF ampMier ouo IC1504 NJM5534MD DOS IC 2nd LO Marker switch 1 501 1246A VC602 TC7SOBF 2rd mixer VCO 2nd LO IC1501 C1502 9A41 0541 2SK210 1st mixer 50M RF Q1211 01212 MMBFUS10 REF butler amplifier Q30 28C4081 1st mixer HF RF DOS IC st LO IC1051 Y IC101 SC 1246A SOHF selection switch IC1081 uPG2009TB 1
4. panel With the AGC set in fixed mode there are three levels for each mode all are adjustable via a menu setting I found this feature useful but I use the fixed AGC settings most of the time Monitor control A variable control as well as an on off switch The audio output was generous and at 3 4 full is strong in mv headphones The audio from the monitor is a very accurate reproduction of the transmitter signal Note Use the monitor to make transmitter adjustments NR Noise Reduction Separate controls for both main and sub RX I found the 7800 NR to be excellent reducing random type noise greatly with a minimal effect on RX audio It is far better than the NR in any of the DSP based radios I ve used in the past NB Noise Blanker Separate controls for Main amp Sub Pushing the button for 1 second or more brings up the adjustment menu There is depth 0 10 and width 0 100 I found the NB to be highly effective on pulse type noise with a fairly regular pulse interval It fell a bit short on random type noise It is still one of the best NB systems I ve ever used There was virtually no distortions The threshold control is on the knob skirt along with the NR control VSC Voice Squelch Circuit soft switch This system was first found on the IC 746Pro It is as it sounds a voice opened squelch I found that it does not function very well in band conditions that are very crowded when most of the noise heard has voice a
5. Adam Farson VA7OJ AB4OJ The transmitter is triple conversion it up converts the 36 kHz DSP IF to 455 kHz and then to 64 455 kHz The high IF is then translated to the transmit frequency Here is an article on the IC 7800 front end Many of you may have heard about roofing filters The 7800 has two of them in the Ist IF one is 15KHz the other is 6KHz These filters reduce the probability that out of band signals and interference can pass into the DSP IF The 15kHz filter is used in amp FM modes the kHz is used in all other modes Little known to many is the fact that there is a different set of filters in the transmit signal path These are 20kHz and 4kHz but don t think for a moment that this means the radio transmits at that bandwidth The code in the DSP system PSN Phase Shift Network for transmit will not allow a bandwidth of more than 2 9kHz on SSB and 6kHz on AM as well as 15kHz for FM There are no modifications that can open up the transmitted occupied bandwidth TOBW it is all hard coded into the DSP softvvare firmvvare The RX filters are fundamental mode monolithic crystal type operating at the 1st IF level The TX filters are ceramic type operating at 455kHz I wondered what the effect would be between the two roofing filters I set up a test to measure it I set my signal generator to act as a Broadcast transmitter with very wide interfering sidebands Then measured the effect of switching the roofing filters
6. CW side tone adjustment only 3 Using the NB I have found that using the NB Noise Blanker is a delicate balance of the three controls available Use only the amount of blanking that is needed to reduce or remove the offending noise Adjust the level up until the noise 15 noticed to be reduced This helps prevent distortions from becoming a problem due to excessive NB levels The NB works best on pulse type noise like a 60Hz AC line noise Noise sources that have frequencies above this will not be reduced much that 15 where the NR should be used There 15 a small amount of interaction between the three level settings a bit of practice will be required to get the best out of this svstem 4 How good is it I have been asked several times Just how good is a 7800 anyway it is really hard to put it into words the two that seem to come the closest are WOW amp Awesome I told a fellow ham that the three best things about the 7800 are the receiver the receiver the receiver 5 A feat of receiver strength While searching for birdies on 40 meters without an antenna connected no pre amp on I was able to fully copy CW signals not just a couple lots of them When I engaged the pre amp the signals become outright loud All with NO antenna The 7800 is the only radio I ve ever owned that is able to do this Nearly all other radios fall completely silent when no antenna is connected Even when I connected the dummy load the
7. With a poor installation you might be able to hear the signals you want but if those stations are not also using a 7800 they might not hear you Go the distance in your installation and the 7800 might make you think it is capable of miracles 13 VVarm up Yes the 7800 does need a short warm up period It takes 5 minutes for the master oscillator to lock onto the proper frequency If the 7800 is powered on from a cold start the displayed frequency will not match the received signal frequency Over about 5 minutes the unit will slowly lock onto the proper frequency This may be a minor annoyance to an impatient operator To avoid this the unit can be placed in standby mode power switch on the rear panel set on orange indicator on front panel give the unit at least 5 minutes in this setting before powering on for operation 14 External display I purchased a 15 flat panel monitor by View Sonic Due to the space restrictions of my radio room and operating position I had to remove the tilting base so the display would sit lower right next to the 7800 I connected it to the external display output on the back panel turned on the monitor but no display I had to go to the display menu to change the default setting from off to on Then the display lit up I noticed that there were ripple type distortions running across the screen so I changed the horizontal sync pulse level from the default setting of H for high to L for low th
8. signals are still copyable on the 7800 try this with any other radio I ll bet you can t do it Oh yeah I didn t find any birdies either 6 Monitor vs On air TX While using the monitor function with head phones on I notice that I can hear background noise in the headphones that others can t hear on my signal when transmitting I compared what I hear on the monitor with what I can hear on an outboard receiver which confirms what other stations have told me Also the signal one hears on the monitor is a very close representation of what will be heard on the air Still an outboard receiver should be used to confirm this The monitor gain is more than enough for most to hear on a good set of headphones A bit of monitor weirdness I noticed that there is a small burst of noise following each transmission while using the monitor to check my transmitter It sounds like the AGC of the monitor circuit ramping down from the time the transmitter is un keyed lasting about half a second This only takes place when using voice modes It sounds a little weird but not a problem as it can only be heard when no other signals or noise are present in the receiver I am not sure of the cause as I am not an engineer I can only offer my best guess 7 Strange receiver start up I have noticed that when the 7800 boots up the receiver does not come up to full operational strength instantly It usually comes up within 1 30 seconds When my shack i
9. to a degree but the figures given are the lower and upper limits of those adjustments There are also an extensive list of EQ settings for each TX mode as well as each RX mode all can be set independent of each other There is some interaction between the TOBW and EQ settings The maximum filter width for receive SSB amp CW 15 3 6kHz 10kHz for AM FM 1s 15kHz Timers Tvvo clocks shovving local and UTC times as vvell as a calendar The unit can be configured to turn on and off vvith these timers much like a VCR can be programmed to run at specific times and on specific dates The timers are backed up when the radio is not powered up by a battery a CR 2032 coin type lithium The battery should last about two years and is easy to change Fit amp finish I should mention the exterior fit amp finish of the 7800 here Aside from being a very heavy radio 551b 25kg the unit has the color of charcoal a kind of gun metal finish It is beautiful There are lots of air vents in the top cover Every part of the cabinet 1s tight and smooth There is lots of real metal in this radio The interior 15 tightly packed with fully shielded boards Not a lot of dead air space in there unlike some other radio brands every inch is filled for a useful purpose All the knobs and switches are tight and smooth It is the highest quality construction I ve seen A masterpiece More hardware Page 4 Fans Three fans one that runs con
10. It is up to the user as to what mic you plan to use I use my trusty old Heil Gold line GM 5 mic which gives me the type of transmit audio I want Bob Heil has developed a mic specifically for the 7800 called the PR 780 I have heard these mics on the air and they sound very good The user will have to decide what type of transmit audio is desired The 7800 can be adjusted to sound just about any way the user wishes but starting with a good mic 15 the basic requirement Choose wisely Here is a list of some of the microphones that I know from personal observations work well on the 7800 Heil GM 5 Gold line Heil PR 780 ICOM SM 20 SM 8 11 TBW amp EQ settings I had to spend a fair amount time working with the TBW adjustments as well as the TX Eq settings I used an outboard receiver to test how each setting affected the received signal My goal is to have full spectrum transmit audio that is balanced well so that when received by other stations using various receive filter band widths my signal would still be fully intelligible With this in mind the TX Eq setting have a good amount of interaction with the TBW settings so each time a setting is changed it must be tested for the results and compared to the previous setting then the next setting can be made and also tested I do not use any compression of any kind and with the mic gain set so that the ALC action is 2 3rds to 3 Aqtr of the ALC range normal for ICOMs I think tha
11. The 7800 does all the decoding and encoding The display above is an FFT amp waterfall display A vector tuning indicator is also provided for PSK Special twin peak filters are set up just for these modes Decoded messages show on the screen and can be stored on the CF card Pre programmed messages for transmit can be stored in memories or retrieved from the CF card Very cool ATU amp Antenna ports The ATU Antenna Tuning Unit is very fast and has memories that allow quick resetting when bands are changed The ATU is only designed to handle an SWR of 3 1 or less The insertion loss 15 enough that the unit requires a fan of its own when 200 watts of RF is applied The ATU should be engaged any time the system SWR is above 1 5 1 to protect the PA section The ATU can also be configured to engage automatically if the SWR goes over 1 5 1 Four antenna ports on the rear panel can be user configured to any number of settings by band or frequency If the user only has one feed line all open ports can be disabled some can be configured as RX only ports There are many possibilities that the user can set Since I have only a single feed line I disengaged the unused ports Plastic caps are provided with the radio to cover unused antenna ports Received audio All modes Wow The RX audio of the 7800 is perhaps the finest I have ever heard Sweet would be another word to describe it The audio is as pure and distortion free as it g
12. a menu selectable item for each mode except FM I found that switching from 15kHz filter to the 6kHz reduced the interfering signal strength by 6dB So they do make a difference If you receive interference try the narrow roofing filter Roofing filters There are two separate AF amplifiers one for the internal and external speaker the other for the headphones Both amps are dual channel stereo type This is an added expense usually found only in high end military and commercial gear SOL gate Q100 0101 25144 AF selecton circuit 0C100 1Ct01 TC4W53F ACC AF output circuit MIC amplifier IC amp 21 NJM2172V 1 Ldd S421 1j slli E 1 x amp keying relay ALC APC circuit 1260 N JM2058M IF ampliher 0506 25582 181 mixer 0506 HSB88WS Jed mixer 1C503 4107 VCA IC105 IC 180 NJM2172V Head phone amplifier IC1 amp 2 111 2 6 IF input switch IC490 TC4WS53F RF amplifier 12820 uPC4094G2 Limit amplifier 12230 uPC4570G2 YOR amplifier n 0801 28C5551 RF amplifier Q508 25 5501 Another high end hardware feature is the incorporation of dedicated DSP boards There are four in all two for the receivers one for the transmitter and one for the spectrum scope The TX and RX boards look identical but close inspection shows that the function is reversed from RX to TX and a few parts have different number
13. ay back controls on the front panel On air recording can be made mic recordings as well but NO on air recordings can NOT be played back on the air directly from this system There is no modification or version that can do this An outboard means would have to be employed but that is left up to the user There are a number of wavs that this can be done CW RTTY amp PSK memories can also be played in the same way as voice Recordings from the air can also be done on these digital modes A large number of controls are duplicated for the sub unit as vvell There are tvvo of almost evervthing More features and functions Page 3 Spectrum scope Quite likelv the single most eve catching feature of the 7800 A high grade spectrum analvzer an awesomelv useful tool a feature unmatched bv others The Pro series comes close but the 7800 goes far bevond artoan ETT SPECTRUM SCOPE CET MAN Geld 6 6 5 0K M imn EUR There are so many features and functions that I could not detail all of them here but rather I ll highlight the most interesting There are 3 sweep rate settings for each span level However with the span set to the finest level a fast sweep rate can cause distorted waveforms This is a common problem in lab grade spectrum analyzers as well The colors of the sweep can be adjusted to nearly any color that can be generated by red green blue mixing These are menu controlled items and can be easily accessed The scope
14. cation allows ICOM into markets to which it would not otherwise have access The 7800 is the first and only amateur radio I have seen with this certification The 7800 is also CE certified First boot up On the rear panel of the 7800 is a large rocker switch this is the main PSU Power Supply Unit power switch This switch must be turned on before the radio can be booted up When the PSU is powered up the light on the front panel switch will glow orange this indicates that the 7800 is in standby mode which warms up the OCXO One could think of the 7800 much like a computer where in the PSU should be powered up first and powered down last Once the PSU switch is on the main power switch on the front panel can be pressed on After pressing the power button several clicks will be heard the power button light will glow green now On the screen will appear the ICOM logo on top and under that will appear the model IC 7800 and under that the user s call sign or anything the user programs into this option up to 10 characters long In the lower right hand corner of the screen will appear the firmware version number in verv small font size All this takes about 5 seconds Gone is the 10 second DSP calibration of the Pro II Many functions on the 7800 will be very familiar to those computer savvv users out there Shutdown 15 a similar affair The power button 15 pressed for at least 1 second and a popup window will appear on the
15. e Front panel 9 007 800 UM ati A AZALMA A mala a 5577 GOF 2 3 TOP VIEW PA UNIT _ ANT SW UNIT MFA FILTER UNIT A mi 8 DIGISEL UNIT mre Yad EN 5777 d OSC UNIT LO I UNIT DC DC UNIT FRONT UNIT 2 4 BOTTOM VIEW OSP A BOARD UN DSP B BOARD B SCOPE UNIT MAIN UNIT OSP TX BOARD eee 882 88 8 9 8 2828 8 5 8 9 28 8 55 8 6 8 2 2 ran 8 5 RXPLL B The IC 7800 receiver is a dual conversion system with the Ist IF at 64 455MHZ and the 2nd DSP IF at 36KHz It accomplishes this huge down conversion step by means of an image reject mixer Interestingly the A amp B receivers are offset by 100kHz to prevent them from feeding back into each other or imposing strong birdies onto each other The Main A Ist IF is 64 455MHz Sub B is 64 555MHz mage rejection mixer l DSP Circuit r t ist LO 1 CW AM and the 4 data modes Note 1 Roofing Filter Note 2 AGC LOOP KG kol A Fig 1 Receiver block diagram Block diagram courtesy of
16. en the ripples went away A few more adjustments on the monitors own settings and it was perfect It is easy to read the external display even from across the room even the smallest print on it is readable 15 External keyboard I purchased a Mini USB keyboard plugged it into the USB port on the back panel of the 7800 and now I can send RTTY and PSK 31 without a PC I tried it out and it works oreat The manual has the instructions on hovv to use the keyboard 16 AC main power glitch On at least one occasion my 7800 has suddenly povvered dovvn and then back on 1 tracked this to AC main voltage drop due to large load changes in the circuit I installed an AC line conditioner which seems to have cured this problem My radio suffered no ill effects but it can t be a good thing to put the unit through repeatedly The switching power supply in the 7800 will shut down when he AC line voltage drops below its tolerance level This protects the supply from damage Using the line conditioner voltage regulator helps to relieve this glitch condition Do NOT under any condition use a variac on switching PS type gear 17 Scope spur I discovered a strange spur in my scope sweep that is present when using the fixed mode I small screen spur with a peak about 1008 above the normal grass level at the bottom of the scope sweep The spur tracks perfectly with the RX center frequency but is offset 36KHz below it on all bands I never
17. ets Simply Awesome There is nothing else out there now that can touch the 7800 in this area Close but not quite Some areas I did not much care for 1 Main knob brake it was either too much or too little adjustment to my liking was not possible so 1 left it at minimum braking The Sub knob has no adjustment at all 2 Only three screen backgrounds and 18 fonts Td like to see more background screen options at least six I could do without some of the font options 3 I would like to see a digital readout for some of the controls such as RF power CW pitch AF and RF gain levels A pop up window could displav the setting each time the control is moved in this way precise settings can be made and repeated very easily By the numbers If you are one who likes to see numbers here are some to chew on These are from the ISO 9000 certification sheet that accompanied my 7800 they are unique to my unit alone Best Sensitivity 0 080 V Minimum guaranteed spec 0 16uV Best carrier suppression 80dB Minimum guaranteed spec 63dB Best RX dynamic range 11118 Minimum guaranteed spec 10908 Best third order intercept point 443dB Minimum guaranteed spec 40dB Best TX RF power output 211 watts Minimum guaranteed spec 190 220 watts The minimum guaranteed specs apply to all IC 7800s most exceed this spec by a large margin The certified measured results insure each unit meets or exceeds the specifica
18. ingly clear when you can copy a station at S 9 but they don t seem to copy well enough to understand So you will have to help his poor receiver with your power amp All receivers are not equal anymore not since the 7800 came along 19 VLF EMI EMC I have recently discovered that there are serious spurious signals in the VLF area of the receiver These are generated by the switching power supply They can be found on 80KHz the primary switching frequency for the power supply with decreasing amplitude on even harmonics and odd harmonics However the receiver is devoid of noise above IMHz The receiver performance is not guaranteed below 1 8MHZ so it is not surprising that there are internally generated noises in the VLF area I look at it this way using the 7800 for dedicated VLF reception is like using a BMW sedan to tow farm implements I did not purchase my 7800 for VLF so this is a non issue for me Those that think it shouldn t be this way may have bought the wrong radio There are far better dedicated VLF receivers than the 7800 so the user that wants high performance in the VLF region should buy one 20 Comparison I have not compared the 7800 to other competing radios since I do not have any of these radios I must purchase each of the radios I review so I can t buy that often As for comparing it to the FTDX 9000 series that isn t going to happen unless someone donates a unit for that purpose any takers Comparing it to
19. ited user configurable filters are built in For the CW operator the 7800 is truly a dream mach ne A special feature for CW is the Auto tune feature which will tune the 7800 to the nearest signal within plus or minus 500HZ It is also usable on AM amp FM where it will tune plus or minus 5kHz range I tested the 7800 side by side with my Pro II hunting very weak CW signals on various bands under a wide range of conditions I found that any signal the 7800 could detect the Pro II could also detect Signals strengths were the same on both radios Where the two differed is the level of noise that was received along with these signals The 7800 had far lower received noise This would make a huge difference in listening fatigue The virtually noise free pre amps of the 7800 can bring a signal from the edge of comfortable receiving up to the arm chair copy level The Pro II pre amps increase the noise level proportionally as well as the desired signal this adds to listening fatigue Even though the Pro II is still an outstanding radio the new but expensive design features of the 7800 place it in a league of its own For weak signal work it IS the ultimate weapon RTTY amp PSK 31 Em L CO DE JASYUA D C DE JAG UA JASVUA KEK PLEASE There are a large number of features for RTTY and PSK 31 Plug ina USB keyboard and your ready to get on the air no TNC or PC needed
20. ll were used units purchased well after they were no longer cutting edge radios This time I went for the gold and got it after only being on the market for a year my personal waiting period This may well be the last high end radio I ever buy new I look at this purchase this way if someone wishes to buy a boat to go fishing they would likely not think twice about spending from 15K to 30K on one but then they would not use it all the time either This radio I can use even in cold or rainy weather late at night during the week etc It does not cost much to operate or maintain but I can t say that about a boat or hot rod For once in my ham career I wanted to be a Lamborghini owner and not just another Chevy driver My financial situation at this time allowed me to do it Do you need this radio Do you need a 30K boat Do you need a 500HP hot rod car Do you want it Sure you do Warning This article is an active article and will not likely be finished for a very long time As I learn more about the radio and the techniques to operate it and get the most performance out of it I shall continue to update this article So come back often to read the new info Description I will not bore the reader by restating the obvious such as describing the front panel or detailing all the functions What I will do is tell the reader about the lesser known design features and things that you may not find in the sales brochur
21. n n UN ER 1 1 s i a E side i Tae 7899 Tom the inside eut By Matt Erickson KKSDR with contributing technical editor Adam Farson VA7OJ AB4OJ All images provided by ICOM Inc eee _ Purchased new March 2005 Serial 012xx RTFM A radio of this level of complexity means one thing the user MUST read the manual several times if needed Don t have time Take the manual with you when you head for the restroom you can t do much other than read while your in there anyway put that time to good use and learn about your radio before you get on the air I m not saying that the radio is hard to operate but there is so much it can do learning all of it without reading the manual would take years In fact the 7800 is very easy to operate nearly ready to go right out of the box Operators that are familiar with the Pro series will understand many of the features and controls on the 7800 very quickiv VVhy Why buy an HF radio for nearly 51 1 000 I asked myself the same thing mv answer was why not It is all about personal choice and budget However due to the massive expense involved in this one radio my new radio purchases for the next ten years will be effectively neutralized The IC 7800 is scheduled to remain in the ICOM product line for about 20 years so I think I m safe with it for at least that amount of time I have had what can be called the ultimate transceiver in several lines but a
22. n in this article came from the users manual service manual other sources and my own observations amp tests Copyright O 2005 M A Erickson KK5DR All rights reserved This page last updated 11 03 05
23. noticed it before but while tuning the bands recently with the scope in fixed mode I saw what appeared to be a small carrier type signal tracking perfectly with my tuning speed and directions I did observe this spur in the centered mode on the scope I placed the span in the 50KHZz and the spur appeared at 36KHz down frequency from the main operating frequency The spur does not seem to cause any problem with the receiver I just think it to be a strange item This is the first item that one could call abnormal but I m not going to send the radio off to ICOM service over it I thought more of a curiosity than a problem I could not observe this spur when band noise or signals mask it usually I can see it when the radio is on a dummy load or a dead very quiet band If you can t see the spur on the scope try this tune the Sub B RX to 36KHz below the main RX frequency engage pre amp 2 disengage any notch filter You should be able to hear a clear carrier if this spur is in your 7800 I would be interested to hear for 7800 owners who can or can t observe this spur 18 Too much receiver Owning the 7800 can have unanticipated effects on your operations The extraordinarv receiver performance will enable you to hear stations that might not be able to fullv read your signal In this case you might have to use an amplifier to help the distant station copy you better overcoming his weaker receiver performance This become glar
24. re There is an Ethernet RJ 45 type connector on the rear panel for remote control firmvvare updates and numerous other functions some of vvhich have yet to be developed There is a lot of extra SDRAM in the unit for future firmvvare updates which tend to increase in size Below is the logic board which contains the SDRAM and main CPU CF controller LAN controller RGB converter for the display etc 2 8 LOGIC UNIT RGB converter IC204 ADV7 123KST50 SDRAM IC201 1C202 481 16 16 2 CPLD IC605 XC9572XL CPLD IC52 XC9572XL GDC IC203 HD64404BT MAIN 2 IC604 HD64F2377 VFQ33V Dual port SRAM 1C51 IDT70V24L25PF MAIN CPU1 1C103 HD6417751RBP200 SDRAM IC1 1C2 MT48LC16M16A2TG LAN controller IC404 RTL8139C CF con troller FAN controller IC401 PCI1410APGE IC621 NJM2904M A feature known as a CF Compact Flash card uses a slot on the front panel This feature allows the user to store his ovvn settings and load them into any 7800 he happens to find Contest stations vvill save valuable time setting up a radio when switching operators The CF card can also be used to do the firmvvare updates that are downloaded from ICOM s web site A card reader writer would be handv for loading the program from hard drive to CF card Voice recordings can also be stored on the card 1 vvas able to view the folder and its contents on mv laptop using mv card reader writer
25. rtifacts in it When monitoring a frequency with little more than background static on it the system seems to work well Steady tones or non coherent noise that is not voice modulated should not open the squelch soft switches are those controls that appear on the left side of the screen associated with the buttons on that side of the screen These switches change according to the mode and or function Digi Sel This is a manual control for the RX pre selector system With this system running in auto mode green light off the center frequency of the tuned pre selector circuit is fixed to the center of the RX frequency With the manual mode engaged green light on the system is able to move the center of the tuned circuit off that of the RX frequency Using my signal generator set as a BC transmitter with a very wide signal I was able to measure the effect While receiving a signal strength of S 9 or more the system reduced the interfering signal strength by 3dB When the interfering signal strength is below S 9 the system reduced the signal by 6dB It stands to reason that even with the system in auto mode BC signals or those of near by transmitters should be reduced by at least the amounts I measured It appears that the farther the center frequency of the receiver is moved from the center of the interfering signal the greater the effect of the Digi Sel system becomes Impressive Record amp Play One touch digital recording and pl
26. s but visually they look the same For perspective the 7800 DSP chipsets have a maximum clock speed of 225MHz and can execute 1350 MIPS Million Instructions Per Second the IC 756Pro II DSP maximum clock speed is 40MHz with 50 MIPS 2 6 DSP A DSP B BOARDS Analog switch 02331 TC7VVS3FK D A converter AF 10551 AK4394 D A corwerter AGC 1077 1 480 DSP IC C1 TMS320C6713GFN 2 7 DSP TX BOARD A D converter AF IC401 AK5394A converter IF IC551 AD1855JRS Clock amplifier IC451 TC7S04FU IC452 SNT4LVC1GUO4DCKR DSP IC IC1 TMS320C8713GFN The 7800 uses a high precision OCXO Oven Controlled Crystal Oscillator at 10 000 000 0 MHz That s right resolution down to 0 1 Hz Stability is 0 05ppm meaning that the signal can be used to calibrate other gear Yep it s that good The unit itself looks like an OCXO I have seen in a high end military frequency counter that cost the government over 11 000 It is very high quality and very expensive It takes 5 minutes after first power up for the unit to stabilize after that there is no more than 1Hz of drift at any time There is an output jack on the rear panel to use the signal as a frequency standard With this radio you can be the most accurate and stable signal on the HF bands Adam amp I have agreed that this OCXO could easily cost ICOM at least 500 each to have manufactured Very expensive but of the highest quality
27. s adjustment need not be used Only negative going ALC voltage is compatible with the 7800 do not use positive ALC voltage Ethernet port The 7800 is equipped with an Ethernet RJ45 port which has an IP address and subnet mask address This port has a mini server installed in it which is currently configured for firmware updating only but that will likely change some day The mini server could be used for radio control The potential is huge On air testing Page 5 Testing the 7800 on the air First I tested the basic background band noise of the 7800 against mv IC 756Pro II because it 1s the only other radio 1 have that even comes close to the 7800 With both radios connected to a two port coax switch and the same antenna Both radios were set to the same AGC filter amp RF gain On 40 meters with no pre amp on the 7800 is at least 608 quieter than the Pro II Next on 17 meters with pre amp 1 turned on on both radios the 7800 is 10085 quieter than the Pro II Next with pre amp 2 turned on on both radios the 7800 15 12dB quieter than the Pro II These tests were performed when the band was dead with no signals heard at anv point on the band Pre amp 1 should be used on 14MHz and up Pre amp 2 should only be used when operating above 24MHz The pre amps are very good they employ negative feed back to reduce noise Both pre amps are nearly noise free Attenuators available are 6 12 18dB but unique to the 7800 pres
28. s cold between 40 60 degrees F The time delay is longer up to 30 seconds Most delay times are 1 5 seconds This has been the only abnormal behavior that I have found I m not certain but it may be perfectly normal for the 7800 8 Scope span When scanning through the scope span ranges I found that to go from a wide or mid setting to a narrow does not require going through all the other wider ranges just press and hold the span button for at least 1 second and the span will jump from where ever it is currently set to the narrowest setting A simple short cut I thought the reader might like to know 9 Speaker output After I studied the schematics I found that there is a relay that disconnects the external speaker and the headphones during transmit Only the headphones can be overridden when the monitor function is on this keeps the head phone line on during transmit so the AF signal can be heard This feature helps prevent RF current from feeding back into the AF circuits If RF feed back is heard in head phones it can be a result of the monitor circuit picking it up or the headphones themselves are acting as an antenna and receiver system This is usually a result of near field RF from an antenna that is much too close to the transceiver or station grounding that is inadequate or near resonate Corrective measures should be taken to prevent this feed back 10 Microphone The 7800 does NOT come with a microphone of any kind
29. screen with the words Shutdown please wait This process takes about 5 seconds Then if the radio it not to be used again for a day or more the main PSU switch should be turned off If the radio is to be used again in a few hours leave the main PSU on The main PSU is protected by a single 15A magnetic circuit breaker These are very fast units usually opening in 5m8 or less Gone are the old auto type fuses which are unreliable and often don t open consistently There is an old type fuse inside the radio which protects the DC output jack 14Vdc 1A max Connection to my PW was very easy Using the synchronization procedure in the PW1 user manual it took only a few minutes ALC adjustment was not needed since the set point was the same as my Pro II everything checked out fine A set of front feet extensions are included with the radio These snap into place and have a fixed angled bottom that tilts the unit back for a better viewing angle Front panel controls of interest RF power output control I plotted the power curve of the range of this control here are the results The 7 o clock position is minimum output 5 watts on SSB zero in all other modes EUR 12 m 12 19 5 m 200 These were the readings for my unit others may vary Drive control This controls the drive stage gain in all modes except for SSB with COMP off AGC VR Variable AGC control can be used when engaged via the switch on the
30. sing the ATT soft switch button for at least 1 second accesses 3 6 9 12 15 18 amp 21dB levels When I operate below 10MHZ I nearly always use some level of attenuation On 80 meters 1 use at least 12 dB 81 the time Maintaining proper signal levels in a DSP svstem will reduce or eliminate distortions Notch test I tested the notch filter system on a constant signal on 14 316MHz This signal 15 a 3 tone signal that can challenge anv notch filter The signal was S 9 at the time of the test The AN or Auto Notch could eliminate the signal but the receiver is desensed and the S meter stavs at S 9 This is prettv common in Auto Notch svstems The MN Manual Notch svstem of the 7800 has three width settings WIDE MID amp NAR NAR could get rid of one tone in the signal mid removed two tones and wide got rid of all three tones but a small amount of tone still get through The MN wide took the signal from S 9 to S 1 This is pretty impressive CW There are a tremendous number of features for the CVV operator These are very refined and useful 1 tested the CW filters on 40 meters and was able to completely remove a signal at 250Hz off center vvith a 500Hz filter There vvere no artifacts at all from an S 9 signal that went to S 1 at that offset No ringing or distortions were noted Super clean filters and smooth operation Full break in QSK is better than in a competing HF rig touted as having the best QSK Virtually unlim
31. st F ampliher 1st LO Q1401 25 55 6154 25210 5 5 FESTA Q1403 25 4402 PLL IC IC201 LMX2306TM Pre HF 8 VCO circuit 1st LO ere g li 4 TURK LO 295651 RX LO switch 1 4 D421 0422 MA77 L Pre ampifer 50M RF Q1209 01210 2505551 Located under side of the point 2 10 RXPLL B UNIT Dos eH owt clock IC851 SC 1287 xha yir NJM5534MD DOS IC 2nd LO Butler her IC501 SC 1246A SCOPE cock Q601 2504215 VCO 2nd LO 2nd mixer Q541 25K210 1C1501 1C1502 9A41 1st mixer 50M R 01211 01212 REF butler amplifier 030 25C5226 1 51 mixer DOS IC 1st LO 1C1051 IC101 SC 1246A SOMF selection switch IC1081 uPG2009TB 1st IF amplifier VCO 1st LO er 2 0156 25 210 Q1402 25C4402 Q1403 28C4402 PLL IC IC201 LMX2306TM Pre ampkter HF RF q Pre ampkter 50M RF 0120901210 2505551 48 saadad aida ali ha naini VCO circuit 1st LO How these receivers are employed is up to the user but one way is to spot DX while rag chewing on another frequency Monitoring or actively hunting with one receiver while running net operations is another way to use it The possibilities are nearly endless The 7800 uses low noise negative feedback pre amps which amplify the signals with minimum S N degradation The 7800 is a fusion of RF hardware and DSP software called Firmwa
32. sweep can be set for a centered sweep found in the 756 series it can also be set for a fixed sweep range Each fixed range is also programmable via a menu setting for each band Selectable sweep spans are 2 5kHz 5kHz 10kHz 25kHz 50kHz 100kHz 250kHz A large number of user configurations are available for the scope The mini scope feature keeps a half size version of the scope on screen while other features and menus are being accessed Virtual meters ANTZ 1 ATT GdB AGGYA EE ia i ard A DU ji Pad 50 BOO om tow Wit Ls 3 25 3 FI are ji In nearlv everv aspect these meters appear to be of the classical analog tvpe They are in fact virtual meters a video reproduction of the original All metered functions can be displayed simultaneously These readings include S meter RF power output compression SWR ALC PA drain voltage and PA temperature A Peak hold function is available as well These meters are extremely fast and accurate very nearlv true PEP reading The level of detail is nothing short of amazing The software engineers even designed in a subtle shadow to the meter needle which makes them appear 3D having virtual depth This is mv favorite aesthetic and functional feature of the 7800 TBW filters The transmitter has three band width settings available Wide 100 to 2900Hz Mid 300 to 2700Hz Nar 500 to 2500Hz This feature was first found in the IC 775DSP These filters are adjustable
33. t I have found the proper setting for my voice Since two voices are exactly the same your settings may vary and your TX audio goals may be different Please don t ask me what my exact settings are because it would be pointless for you to use them since your voice is not exactly like mine You will have to work to find your own unique group of settings as per your goals in TX sound The TBW selections can be set up so adaptation to changing band conditions or operating goals can be quickly changed at the press of a button 12 What it is It would be easier to tell the reader what the 7800 isn t rather than what it 1s First of all the 7800 1s NOT a miracle machine A user can not aspect the 7800 to work it s magic with an impossible installation Poor grounding poor antennas high noise locations amp bad operators can make even the most expensive radio made perform like a pile of junk ICOM has gone the distance in designing the finest radio in existence it is the least a user can do to provide a good installation to let it strut it s stuff Complaining about RF feed back when the antenna is only 10 feet away from the radio the station ground is very long in poor soil is not a good installation and RF feed back 15 nearly a foregone conclusion complaints will not fix this A good antenna is perhaps the most important investment in a station installation An antenna of extreme compromise will perform like an extreme compromise
34. the Orion II that will not happen either Ten Tec gear is not on my list of approved vendors So don t ask me how the 7800 compares to other radios there simply isn t any other radio in the ham market that can currently touch it In my humble opinion 21 Non ham comparative Perhaps the only HF radios that would compare well or exceed the 7800 basic receiver performance would be a few of the models made by Rohde amp Schwarz or Rockwell Collins but these range in price from 40K to 60K each These radios are rather Spartan and lack many of the features that hams have come to demand they are tools very utilitarian idiot proof It has been speculated that there are several non ham models of the 7800 that have features and capabilities that are only used by military and some commercial government customers ICOM will not confirm or deny any of this It IS known that stock 7800 s are used by some government agencies and special ops military units About one year after the 7800 was released the sales figures were about 250 units sold to hams and 1000 units sold to military government buyers These numbers are well above this now The entire 2005 production run has been sold out or allotted to dealers A great start for a model that is intended to stay in ICOM s product line for about 20 years If you have a specific question about this radio please send an e mail I ll answer it as best I can 73 de Matt All of the informatio
35. tinuously in the PSU one in the ATU and one in the PA section The fan in the PSU and ATU are common 3 inch Muffin fans and are very quiet The PA fan is a 10 inch wide scroll fan and is super quiet The 7800 stays cool all the time Only slight warming is found in the rear area where the warm air exits the PA heat sink Special band coverage The US version of the 7800 covers the 60 meter band without any modifications The Euro version can be used for the 137KHz band as a receiver front end the transverter output can be used with an outboard BPF LPF unit and PA for operation on that band There are at least 10 versions of the 7800 available I suspect there are many more that are custom configured for specific customers who wish to remain anonymous Non ICOM amplifiers The 7800 can key non ICOM amplifiers but the keying relay has the same old limits The relay is limited to 16V 0 5A Something new was added to the 7800 keying circuit a MOSFET relay rated at 250Vac 200mA This feature can be activated via a menu setting If you have an amplifier whose keying voltage current that is too high you will need an outboard buffer relay The standard ALC for nearly all ICOM radios is 0 to 4Vdc However the 7800 has an additional ALC level adjustment on the rear panel which allows the user to control an amplifier whose ALC voltage output is greater than 4Vdc If you use an amp that does not put out more than 4Vde thi
36. tions Closing thoughts and updates Page 6 My personal thoughts on the 7800 In my opinion the IC 7800 is the finest radio 1 have ever had the privilege of owning and operating In nearlv all areas it has met or exceeded my expectations I feel that 1 can be very happy for many years to come with this masterpiece of radio engineering This radio 15 likelv to become a classic in about a decade just as the IC 781 d d No radio 15 perfect but this one 15 as close as Tve seen to it Updates Future updates to this article vvill appear here Please be sure to return from time to time to see vvhat 1s nevv 1 Auto tune The CW feature Auto tune is what it implies when in CW mode the radio will tune automaticallv to the nearest CW signal and lock onto it with the standard 700Hz zero beat It does this regardless of the CW pitch control setting The svstem works good on an un crowded band but becomes a bit erratic on CW pile ups or in noisv conditions The Auto tune feature also works on AM I found that it worked well but could lock onto a strong SSB signal 2 CW pitch I measured the frequencv of the CW pitch control settings Starting at the fullv counter clockwise position the frequencv is 300Hz At the Noon position it is 600Hz 700Hz is slightly clockwise past the lo clock position Fully clockwise position is 900Hz the CW pitch control has nothing to do with the CW filter selection or PBT adjustments it is for receive
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