[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-676600-105":3,"detail-sidebar-cat-0-en-105":79,"doc-detail-676600-en":129},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":72,"head_meta":74,"extra_data":76,"updated_unix":78},105,"en","walker-ii-eu-specifications-service-manual","WALKER II EU - Specifications - Service Manual","","WALKER II EU service manual provides detailed specifications and circuit description for the radio system. It lists operating frequency coverage, modulation modes (F3E FM, A3E AM), channel configurations, electrical characteristics such as antenna impedance, supply voltage, temperature range, and current drain. Receiver sections cover double-conversion architecture, IF frequencies, sensitivity, filtering, gain stages, squelch operation, and audio amplification routing. Transmitter sections describe modulation paths, power amplifier stages, harmonic suppression, and control functions including MCU timing, TX/RX switching, display interfacing, and power regulation outputs.",{"@graph":14,"@context":71},[15,34,54],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/technology/","Technology",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/walker-ii-eu-specifications-service-manual/676600/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":48,"encodingFormat":47,"isAccessibleForFree":49,"interactionStatistic":50},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/walker-ii-eu-specifications-service-manual/676600.png","ImageObject",300,407,{"name":42,"@type":43},"Asher","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-11-04",true,{"@type":51,"interactionType":52,"userInteractionCount":4},"InteractionCounter",{"@type":53},"ViewAction",{"@type":55,"mainEntity":56},"FAQPage",[57,63,67],{"name":58,"@type":59,"acceptedAnswer":60},"What frequency range and operating modes does WALKER II EU support?","Question",{"text":61,"@type":62},"It covers 26.965 ~ 27.405 MHz and operates in F3E (FM) and A3E (AM) modes.","Answer",{"name":64,"@type":59,"acceptedAnswer":65},"How is the receiver IF implemented in the WALKER II EU?",{"text":66,"@type":62},"The receiver uses double conversion: a first IF at 10.695 MHz and a second IF at 455 kHz, with dedicated filtering stages.",{"name":68,"@type":59,"acceptedAnswer":69},"What are the main transmitter signal flow and power amplifier considerations?",{"text":70,"@type":62},"Microphone audio is amplified and fed to the VCO module for direct FM modulation (AM path described through RF amplifier stages). The transmit output is buffer-amplified, further amplified through final amplifiers, passes a low-pass filter to suppress high-frequency harmonics, and is routed to the antenna terminal.","https://schema.org",{"og:url":32,"og:type":73,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":75,"canonical":32},"index,follow",{"doc_id":77,"site_id":7},676600,1793776206,{"code":4,"msg":80,"data":81},"success",[82,86,90,94,99,103,108,113,118,121,125],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":83,"show_sort_weight":84,"slug":85},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":87,"show_sort_weight":88,"slug":89},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":91,"show_sort_weight":92,"slug":93},"Exam",70,"exam",{"id":95,"doc_module":4,"doc_module_name":25,"category_name":96,"show_sort_weight":97,"slug":98},5,"Comic",60,"comic",{"id":100,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":101,"slug":102},6,50,"technology",{"id":104,"doc_module":4,"doc_module_name":25,"category_name":105,"show_sort_weight":106,"slug":107},7,"Healthcare",40,"healthcare",{"id":109,"doc_module":4,"doc_module_name":25,"category_name":110,"show_sort_weight":111,"slug":112},8,"Research & Report",30,"research-report",{"id":114,"doc_module":4,"doc_module_name":25,"category_name":115,"show_sort_weight":116,"slug":117},9,"Religion & Spirituality",20,"religion-spirituality",{"id":116,"doc_module":4,"doc_module_name":25,"category_name":119,"show_sort_weight":116,"slug":120},"World Cup","world-cup",{"id":122,"doc_module":4,"doc_module_name":25,"category_name":123,"show_sort_weight":122,"slug":124},10,"Lifestyle","lifestyle",{"id":126,"doc_module":4,"doc_module_name":25,"category_name":127,"show_sort_weight":95,"slug":128},19,"General","general",{"code":4,"msg":80,"data":130},{"doc_id":77,"user_id":131,"nickname":42,"user_avatar":132,"doc_module":4,"category_id":100,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":133,"file_id":134,"file_url":135,"file_type":136,"file_size":137,"view_count":4,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":138,"language":139,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":12,"update_tm":78,"read_time":143},687197207639,"https://ap-avatar.wpscdn.com/davatar_a8503ba1806abce46bf441b54a3ca4cd","WALKER II EU  \nSERVICE MANUAL  \nWALKER II EU  \nSPECIFICATIONS  \n\n| General |  |  |\n| --- | --- | --- |\n| Frequency coverage |  | 26.965 ~ 27.405MHz |\n| Operating mode |  | F3E (FM), A3E (AM) |\n| Number of channels |  | 40 EU / 40 PL / 80 d / 40 EC / 40 UK+40 CEPT / 27 In |\n| Antenna Impedance |  | 50 Ω |\n| Working temperature |  | –10℃~+55℃ |\n| Frequency Tolerance |  | Better than 0.002% |\n| Input Voltage |  | 13.2V DC |\n| Grounding Method |  | Negative ground |\n| Current Drain | Transmitter | 3.0A Max. |\n|  | Receiver | About 300mA 0.8A (VOL Max. ) |\n| Dimensions (W x H x D) With projections |  | Microphone: 60 x 41 x 82 mm\u003Cbr>Body: 170 x 202 x 52 mm |\n| Weight |  | Approx.1Kg |\n| RECEIVER |  |  |\n| Receiving System |  | Dual conversion superheterodyne |\n| IF Frequencies |  | Double Conversion 1st 10.695MHz/ 2nd 455KHz |\n| Sensitivity |  | -112dBm for 20dB SINAD in AM Mode |\n|  |  | -117dBm for 20dB SINAD in FM Mode |\n| Audio Output Power |  | 3 watts max @8 Ω |\n| Audio Distortion |  |  |\n|  |  | Less than 5% @ 1KHz |\n| Image Rejection |  | 70dB |\n| Adjacent Channel Rejection |  | 60dB |\n| Frequency Response |  | 300Hz to 3000Hz |\n| Squelch |  | Less than 1.0μV |\n| TRANSMITTER |  |  |\n| Output Power |  | FM/AM: 4.0 W |\n| Modulated signal distortion |  | Inferior to 5% |\n| Frequency Response |  | 300Hz to 3000Hz |\n| Output Impedance |  | 50ohms, Unbalanced |\n| Harmonic Suppression |  | More than-54dBm |\n\nCIRCUIT DESCRIPTION  \nFrequency configuration  \nThe receiver utilizes double conversion. The first IF is 10.695MHz and the second IF is 455kHz. The first local oscillator signal is supplied from the VCO module.  \nThe VCO module in the transmitter generates the necessary frequencies. Fig. 1 shows the frequencies.  \nFig. 1 Frequency configuration  \nReceiver  \nThe frequency configuration of the receiver is shown in Fig. 2.  \n􀂄 Front-end RF amplifier  \nAn incoming signal from the antenna is applied to an RF amplifier (Q103) after passing through a transmit/receive switch circuit (D108 and D109 are off) . After the signal is filtered through a band pass filter (L103, L104 and L105) to eliminate unwanted signals before it is passed to the first mixer.  \n􀂄 First Mixer  \nThe signal from the RF amplifier is heterodyned with the first local oscillator signal from the VCO module at the first mixer (Q104) to create a 10.695MHz first intermediate frequency (1st IF) signal. The first IF signal is filtered through a band pass filter (L106, L107and L108) and then fed through the monolithic crystal filter (MCFs : CB100) to further remove spurious signals.  \nThe band-pass filters are tuned to a desired frequency by varicaps (D112, D113, D114,) . A tuning voltage corresponding to the desired signal is applied to each varicap through the DC amplifier of the U303B to tune to the receive frequency.  \n􀂄 IF amplifier  \nThe first IF signal go into second mixer Q113, second mixer mix first IF and 10.24MHZ second IF output Y100 . The signal is heterodyned again with a second local oscillator signal. The second IF signal is then fed through a 455kHz ceramic filter (CF100) to further eliminate unwanted signals. The signal is amplified by Q114 and Q105, and then the second IF signal enter U101 (FM processing IC) in FM mode or changed  \nCIRCUIT DESCRIPTION  \naccording to D117 diode DC and receive audio signal output.  \nANT  \nFig. 2 Receiver section configuration  \n􀂄 AF amplifier  \nThe FM IC output the FM AF passes through the AF amplifier (U307B) or The AM AF through the D117 and AF amplifier (U307B), and AF switch (U304),and Electrical Control Volume IC(U302) . After goes to AF power amplifier IC (U305) . Is routed to an audio power amplifier (U305) where it is amplified and output to the speaker. To output sounds from the speaker, U701 sends a high signal to the SPMUT line the turns Q317 .  \n􀂄 Squelch  \nA squelch circuit is provided to prevent no-signal noise or weak signals from outputting to a speaker during transmission.  \nTransmitter  \n􀂄 Transmit audi","cbCaikMjNf5FsnPT","https://ap.wps.com/l/cbCaikMjNf5FsnPT","pdf",3572169,37,"English","# General Specifications\n## Receiver Specifications\n## Transmitter Specifications\n# Circuit Description\n## Frequency Configuration\n## Receiver Section Configuration\n## AF Amplifier and Squelch\n## Transmit Circuit and Power Amplifier\n## Power Supply and Control Circuit\n## Display Circuit\n# LCD Unit","[{\"question\":\"What frequency range and operating modes does WALKER II EU support?\",\"answer\":\"It covers 26.965 ~ 27.405 MHz and operates in F3E (FM) and A3E (AM) modes.\"},{\"question\":\"How is the receiver IF implemented in the WALKER II EU?\",\"answer\":\"The receiver uses double conversion: a first IF at 10.695 MHz and a second IF at 455 kHz, with dedicated filtering stages.\"},{\"question\":\"What are the main transmitter signal flow and power amplifier considerations?\",\"answer\":\"Microphone audio is amplified and fed to the VCO module for direct FM modulation (AM path described through RF amplifier stages). The transmit output is buffer-amplified, further amplified through final amplifiers, passes a low-pass filter to suppress high-frequency harmonics, and is routed to the antenna terminal.\"}]","WALKER II EU - Specifications - Service Manual | PDF",93]