Web-888 with the Hammarlund HQ-180
Intraband Panadapter and Complete Coverage Extension — A Two-Role Integration Unlike Any Other in This Series
Every other vintage receiver in the vk6ada.com.au Web-888 series covers the full HF spectrum — the SP-600 from 540 kHz to 54 MHz, the R-388 from 540 kHz to 30.5 MHz. The Hammarlund HQ-180 does not. It covers the amateur bands: 80 m, 40 m, 20 m, 15 m, and 10 m. Between those bands — and below 80 m and above 10 m — the HQ-180 is silent. The Web-888 changes this. It provides the intraband panadapter that shows what is happening within each amateur band while the HQ-180 listens, and it independently provides coverage of all the shortwave frequencies between and beyond the amateur bands that the HQ-180 cannot reach at all.
The HQ-180 integration is fundamentally different from every other Web-888 pairing in this series because of one architectural fact: the HQ-180 covers only the amateur bands. The SP-600 guide and the R-388 guide address receivers that cover the full HF spectrum from the lower shortwave bands through 30 MHz and beyond. With those receivers, the Web-888’s role is always additive within a range the receiver already covers: providing the visual panadapter that the analogue receiver cannot display. With the HQ-180, the Web-888 has an additional role that does not exist in any other pairing in this series: it provides coverage of HF frequencies that the HQ-180 cannot receive at all.
This creates a genuinely two-role integration. Role 1: the Web-888 connected to the HQ-180’s 455 kHz second IF provides an intraband panadapter — a visual display of the amateur band the HQ-180 is currently operating on, following the HQ-180’s VFO automatically, showing the DX signals and activity around the HQ-180’s tuned frequency. Role 2: the Web-888 connected independently to a dedicated receive antenna (or via an antenna splitter) provides coverage of all the SW broadcast bands, utility stations, and HF frequencies between the amateur bands that the HQ-180 cannot receive. The operator can listen to an amateur band on the HQ-180 while simultaneously monitoring a shortwave broadcast or utility frequency on the Web-888 — a combination that no single instrument in this collection provides alone.
Web-888 receives the HQ-180’s 455 kHz second IF output. OpenWebRX displays the amateur band the HQ-180 is on, centred on the HQ-180’s VFO frequency. The panadapter shows signals within the amateur band: DX stations, pile-ups, net activity, beacons. The HQ-180 provides the audio; the Web-888 provides the visual context. This role is identical in principle to the R-388 and SP-600 IF tap integrations.
Role 2 — Coverage Extension (via dedicated antenna or splitter):
Web-888 connected to its own antenna (or via splitter to the HQ-180’s primary antenna) displays the FULL HF spectrum simultaneously. While the HQ-180 is on 20 m, the Web-888 independently shows activity on 49 m SW broadcasts, 31 m broadcasts, VOLMET on 10.051 MHz, maritime on 8.291 MHz, and any other HF frequency. This coverage extension role does not exist for the SP-600 or R-388 pairings because those receivers already cover the full HF spectrum.
Most operators will implement both roles simultaneously: the IF tap connection for Role 1 plus a dedicated short wire antenna for Role 2. Both roles run concurrently, with the operator selecting which Web-888 profile to view depending on what they want to see.
Section 1 — HQ-180 Architecture: Amateur Bands, Dual Conversion, and VFO Tuning
Amateur Band-Only Coverage
The Hammarlund HQ-180 was designed specifically for licensed amateur radio operation. Its frequency coverage spans the standard HF amateur bands available at the time of its production:
- 80 metres: approximately 3.4–4.0 MHz (covers the 80/75 m amateur band)
- 40 metres: approximately 6.9–7.5 MHz (covers the 40 m amateur band)
- 20 metres: approximately 13.7–14.5 MHz (covers the 20 m DX band)
- 15 metres: approximately 20.9–21.5 MHz (covers the 15 m band)
- 10 metres: approximately 27.7–30.0 MHz (covers the primary 10 m segment)
The HQ-180 does not tune to the frequencies between these bands. An operator who wants to hear a shortwave broadcast on 9.650 MHz (31m band) or a maritime distress call on 8.291 MHz, or any of the ITU broadcast bands between the amateur allocations, cannot access those frequencies on the HQ-180. This is not a design flaw — the HQ-180 was designed for its intended application — but it creates a coverage gap that the Web-888 fills in a way that no other instrument in this comparison does.
Dual Conversion and the 455 kHz Second IF
The HQ-180 uses a dual-conversion superheterodyne design on its upper band positions (20 m, 15 m, 10 m), with a first conversion stage providing image rejection followed by a second conversion to the standard 455 kHz IF. The 80 m and 40 m positions may use a single conversion to 455 kHz depending on the specific HQ-180 variant; consult the service manual for the specific unit. In all band positions, the final selectivity and demodulation occur at 455 kHz — the tap point for the Web-888 cascade integration.
VFO Tuning Within Bands
The HQ-180 uses a variable frequency oscillator (VFO) for continuous tuning within each selected amateur band. Unlike the Collins PTO (which uses a precision lead screw mechanism) or the Hammarlund SP-600’s separate preselector, the HQ-180’s VFO is a conventional LC oscillator that tunes smoothly across the selected band. The VFO dial provides the main tuning control; the bandswitch selects which amateur band is active.
For the Web-888 IF tap integration, the VFO determines the frequency content of the 455 kHz IF: as the operator rotates the HQ-180’s tuning dial, the signals in the 455 kHz IF shift accordingly, and the Web-888 panadapter tracks these changes. The panadapter centre frequency follows the VFO dial automatically. Unlike the SP-600, there is no separate preselector to peak; unlike the R-388, there is no PTO with 10-turn vernier precision. The HQ-180’s VFO dial provides good tuning control for amateur band operation and adequate frequency identification for most SWL monitoring purposes.
Modes and Selectivity
The HQ-180 provides AM reception (standard envelope detection), CW (BFO engaged, narrow filter), and SSB (via BFO offset for USB or LSB, with some variant-specific differences). Multiple bandwidth positions are available, from a wide AM position through progressively narrower CW positions. The audio quality of the HQ-180 is a consistent community compliment: the audio chain is well-designed for its era, and the receiver produces pleasant, musical AM audio that the Hammarlund community values specifically.
Section 2 — The Combined Coverage Picture: HQ-180 + Web-888 Together
80m: 3.4–4.0 MHz ● SSB, CW, AM
40m: 6.9–7.5 MHz ● SSB, CW, AM
20m: 13.7–14.5 MHz ● SSB, CW, AM
15m: 20.9–21.5 MHz ● SSB, CW, AM
10m: 27.7–30.0 MHz ● SSB, CW, AM
NOT covered: any frequency between or outside these bands — no SW broadcasts, no utility stations, no 30m/17m/12m WARC bands, no maritime frequencies, no medium wave
All SW broadcast bands: 120m through 11m (2.3–26.1 MHz)
WARC amateur bands: 30m (10.1 MHz), 17m (18.1 MHz), 12m (24.9 MHz)
Maritime HF: 4.125, 6.215, 8.291, 12.290 MHz
VOLMET aviation: 3.485, 5.450, 6.679, 10.051, 13.282 MHz
Medium wave: 530–1700 kHz (AM broadcast)
160m: 1.8–2.0 MHz amateur band
Intraband role: within each amateur band, the Web-888 via the IF tap shows the visual panadapter alongside the HQ-180’s audio on the same band segment
Section 3 — Three Integration Approaches (Including a Unique HQ-180 Option)
Section 4 — Approach 1 / Approach 2: IF Tap Installation in the HQ-180
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1
Power off; discharge and verify; access the IF section Unplug from mains. Allow capacitors to discharge. Verify all supplies below 30 V with DVM. Remove the HQ-180’s top cover (typically four screws). The second IF section is identifiable from the service manual chassis layout — look for the IF transformer cans near the detector stage.
-
2
Locate the 455 kHz second IF tap point from the service manual The HQ-180 service manual circuit diagram and chassis layout identify the second IF section. The tap point is at a convenient access to the 455 kHz signal before the bandwidth-selection filter network — allowing the full available IF bandwidth to appear on the Web-888 panadapter. Contact vk6ada.com.au for the HQ-180-specific buffer kit documentation with the tap point identified for each HQ-180 production variant.
-
3
Install buffer PCB; route RG-174 tap lead; drill rear-panel BNC Mount the buffer PCB at a suitable chassis standoff. Route a short RG-174 coax from the tap point to the PCB input. Drill the 15 mm rear-panel BNC aperture from outside the chassis. Route the PCB output BNC cable to the rear-panel connector. Power the buffer from a suitable low-voltage supply point in the HQ-180 (identified in the kit documentation). For Approach 2 (dual role), if the Web-888 has a second HF input, the dedicated short wire antenna connects there; otherwise, use an external BNC A/B input selector switch.
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4
Verify HQ-180 sensitivity unchanged; test Web-888 signal on each amateur band Power on. Confirm the HQ-180 receives normally on all five band positions. Connect the rear-panel IF tap BNC to the Web-888. Open OpenWebRX, set centre to
455 kHz, apply the 20 m IF offset (14.150 MHz − 455 kHz = 13.695 MHz). Switch the HQ-180 to 20 m; signals should appear on the panadapter. Slowly rotate the HQ-180 VFO; signals should shift across the panadapter, confirming the IF tap is working. Repeat verification on all five band positions.
Offset (Hz) = HQ-180 dial reading (Hz) − 455,000 Hz80m SSB phone segment (~3.750 MHz): offset =
3,295,000 Hz (3.295 MHz)40m SSB phone segment (~7.200 MHz): offset =
6,745,000 Hz (6.745 MHz)20m DX segment (~14.200 MHz): offset =
13,745,000 Hz (13.745 MHz)15m DX segment (~21.200 MHz): offset =
20,745,000 Hz (20.745 MHz)10m phone segment (~28.400 MHz): offset =
27,945,000 Hz (27.945 MHz)Band change procedure: when the HQ-180 bandswitch moves to a new amateur band, update the OpenWebRX IF offset to match. The offset changes significantly between bands (several MHz difference). Pre-configure one OpenWebRX IF tap profile per amateur band with the mid-band offset pre-entered; select the profile on each band change.
Section 5 — OpenWebRX Profile Configuration for Both Roles
Role 1 Profiles: Intraband Amateur Band Panadapter (IF Tap Input)
Create five IF tap profiles — one per amateur band. Each profile is set to receive at 455 kHz with the mid-band offset for the corresponding band pre-configured. Name the profiles clearly so band changes are a single click: “80m — IF Tap”, “40m — IF Tap”, “20m — IF Tap”, “15m — IF Tap”, “10m — IF Tap”. The OpenWebRX display mode for 80m and 40m profiles should default to LSB; 20m, 15m, and 10m profiles should default to USB. Set the display span for each band to show the full amateur band allocation: 500 kHz for 80m and 40m, 500 kHz for 20m and 15m, 1 MHz for 10m.
Role 2 Profiles: Coverage Extension (Dedicated Antenna Input)
Create profiles for the frequency ranges the HQ-180 cannot receive. These are set to direct HF frequency (no IF offset, since the dedicated antenna input receives the raw HF signal). Priority profiles for the HQ-180 coverage extension role:
- SW broadcast bands the HQ-180 misses: 31m (9.400–9.900 MHz), 25m (11.600–12.100 MHz), 49m (5.900–6.200 MHz), 41m (7.100–7.350 MHz overlaps with 40m amateur — useful for broadcast monitoring while HQ-180 is on 40m amateur), 19m (15.100–15.800 MHz), 16m (17.480–17.900 MHz)
- WARC amateur bands: 30m (10.100–10.150 MHz), 17m (18.068–18.168 MHz), 12m (24.890–24.990 MHz) — none of these are covered by the HQ-180
- 160m amateur band: 1.800–2.000 MHz — the HQ-180 does not cover 160m
- Utility frequencies: VOLMET (5.450, 10.051, 13.282 MHz), maritime (4.125, 8.291 MHz)
- WWV time standards: 5.000, 10.000, 15.000 MHz — useful for propagation reference and calibration
Section 6 — Eight Best-Practice Operating Procedures for the HQ-180 + Web-888 Station
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Intraband Panadapter: Selecting the Correct IF Tap Profile on Each Band Change
The HQ-180’s bandswitch and the Web-888’s IF tap profile must be kept in sync. When the HQ-180 moves from 20m to 40m, the IF offset changes by approximately 7 MHz; signals in the panadapter will appear at the wrong frequencies until the OpenWebRX profile is updated to the 40m IF tap profile. Establish a discipline: rotate the HQ-180 bandswitch → immediately select the corresponding OpenWebRX IF tap profile → then tune the HQ-180 VFO to the desired frequency.
The practical benefit of the intraband panadapter across all five HQ-180 bands is different on each band. On 20m and 15m (500 kHz allocation each), the panadapter shows the full DX SSB segment and the CW segment simultaneously — pile-up activity is immediately visible. On 80m (600 kHz allocation), the panadapter shows both the phone and CW portions of the band. On 10m (1.7 MHz covered by the HQ-180), the panadapter shows whether the band is open and which portions are active, which is the primary uncertainty in 10m operating during all but the most active solar maximum periods.
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Coverage Extension: Monitoring Between the Amateur Bands While HQ-180 Holds a Frequency
The coverage extension role (Role 2) is most valuable when the HQ-180 is monitoring a slow-activity frequency that requires occasional attention but not constant tuning — a club net on 80m SSB that has predictable check-in intervals, a CW net with slow traffic flow, or a specific amateur station being monitored for propagation assessment. During the gaps between activity on the HQ-180, the operator can view the Web-888’s dedicated antenna profiles for SW broadcast reception, utility station monitoring, or WARC band DX assessment.
This parallel monitoring discipline is unique to the HQ-180 integration: it genuinely extends the operator’s awareness beyond what any single instrument in the collection provides. While listening to the 20m net on the HQ-180, open the Web-888 17m profile on the coverage extension input. If 17m is showing DX activity, note the frequencies for investigation after the net. The HQ-180 holds the net frequency; the Web-888 acts as a background spectrum scanner that surfaces opportunities the operator would otherwise miss while focused on the HQ-180.
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DX Panadapter Navigation: Identifying Pile-Ups and DX Station Positions
The intraband panadapter (IF tap, Role 1) is particularly valuable for DX monitoring on 20m, 15m, and 10m. A DX station working a pile-up produces a characteristic waterfall signature: the DX station’s transmit appears as a single, relatively narrow peak; the pile-up of calling stations appears as a cluster of peaks slightly offset from the DX station (in split operation). The DX station’s listening frequency — where the pile-up is calling — is visible as the denser cluster.
Using the panadapter for pile-up navigation with the HQ-180: tune the HQ-180 VFO to the DX station’s transmit frequency; identify the pile-up cluster frequency from the panadapter; note the approximate centre of the pile-up; retune the HQ-180 to the pile-up cluster frequency to listen to calling stations (this tells the operator what split the DX is working). Return to the DX station’s transmit frequency to listen for acknowledgements. This navigation pattern is significantly faster with the panadapter than by audio scanning alone, where the operator must listen through the pile-up to identify the split pattern.
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WARC Band Monitoring via Coverage Extension — Bands the HQ-180 Cannot Reach
The WARC bands (30m at 10.1 MHz, 17m at 18.1 MHz, and 12m at 24.9 MHz) were allocated in 1979 and are not covered by the HQ-180. The Web-888 coverage extension role provides access to these bands that the HQ-180’s design never anticipated. Configure the Web-888’s dedicated antenna profiles for all three WARC bands; during Solar Cycle 25 maximum conditions (2025–2026), 17m and 12m are frequently open for trans-oceanic DX with less congestion than 20m and 15m.
The WARC band coverage extension is a qualitatively new capability for the HQ-180 owner: these bands never existed in the receiver’s original design context, and no modification of the HQ-180 itself could add them. The Web-888 adds them entirely through its own independent coverage, with no interaction required with the HQ-180. Configure the 17m profile (18.068–18.168 MHz, USB, 200 kHz span) and the 12m profile (24.890–24.990 MHz, USB, 150 kHz span) as standard profiles in the coverage extension input. The 30m profile (10.100–10.150 MHz, CW/data, 100 kHz span) is useful for CW monitoring when the HQ-180 is on 40m or 20m.
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SW Broadcast Monitoring Between Amateur Sessions
When the HQ-180 is not in active use for amateur band monitoring, the Web-888 coverage extension input provides the complete international shortwave broadcast experience that the HQ-180 alone cannot deliver. Between amateur operating sessions (club nets, DX openings, contest periods), use the Web-888’s SW broadcast profiles (31m, 25m, 19m, 16m, and others from the ITU broadcast band table) to monitor international broadcasters. BBC World Service, Voice of America, Radio New Zealand International, and similar broadcasters remain active on shortwave and are accessible on the Web-888’s coverage extension input without any adjustment to the HQ-180.
The combined station workflow: during amateur activity periods, use HQ-180 for audio (Role 1 IF tap panadapter for visual context). During non-amateur periods, switch the Web-888 to coverage extension profile (Role 2) and use the Web-888’s OpenWebRX audio for broadcast monitoring. The HQ-180 can remain powered and available on an amateur frequency without interfering with the Web-888’s coverage extension monitoring.
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10m Band Opening Detection via Web-888 Coverage Extension
The HQ-180 covers 10m (approximately 27.7–30.0 MHz) but the band is irregular in activity: during Solar Cycle 25 maximum (2025–2026) it is frequently open, but distinguishing an open band from a dead band requires tuning through the HQ-180’s 10m segment manually. The Web-888 coverage extension profile for 10m (28.0–29.7 MHz, USB, 1 MHz span) shows whether the band is open at a glance without requiring the HQ-180 to be switched to 10m and manually scanned.
10m opening detection procedure: keep a Web-888 10m profile (direct HF frequency, 28.000–29.700 MHz, 1 MHz span) as a background monitoring profile on the coverage extension input. Periodic glances at this profile during an operating session on another band reveal 10m openings as clusters of signal activity appearing on the panadapter. When the profile shows significant 10m activity, switch the HQ-180 to 10m and the Web-888 IF tap to the 10m profile for intraband monitoring of the opening.
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CW Net Monitoring with Narrow Filter and Panadapter
The HQ-180’s narrow CW filter positions provide the selectivity needed for CW net monitoring on crowded bands. The Web-888 intraband panadapter (IF tap, Role 1) shows the CW signals in the vicinity of the HQ-180’s tuned frequency as individual vertical lines during key-down periods. Each visible CW signal peak corresponds to a station transmitting; the pattern of peaks on the panadapter shows how many stations are active near the net frequency and their approximate relative frequencies.
This is particularly useful on 40m CW (7.000–7.100 MHz), where the CW portion of the band is shared with many stations and the panadapter provides a visual map of the local band occupancy. Select the narrow CW filter on the HQ-180 for audio; set the Web-888 40m IF tap profile to a 100 kHz span to show the immediate 100 kHz window around the net frequency. Tune the HQ-180 VFO to the net’s nominal frequency; signals appearing slightly offset from the expected net frequency are immediately visible as panadapter peaks offset from the display centre.
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160m Coverage Extension — the Amateur Band the HQ-180 Cannot Reach
The 160m amateur band (1.800–2.000 MHz) is a significant omission from the HQ-180’s coverage. As with the WARC bands, the Web-888’s coverage extension role provides 160m access that the HQ-180 cannot give. Configure a 160m coverage extension profile (1.800–2.000 MHz, LSB, 200 kHz span) for the dedicated antenna input. The 160m band is active primarily at night in temperate regions; during the HQ-180’s quiet periods (daytime, or during periods when the HQ-180 operator is not actively monitoring), the Web-888’s 160m profile can monitor for activity.
The 160m Web-888 profile also shows medium-wave AM broadcast stations in the adjacent 530–1700 kHz range when the profile is set wide enough. MW broadcast monitoring via the Web-888 with a 200 kHz span set to the AM broadcast band (centre at 1.100 MHz, 1.2 MHz span) shows regional and international AM broadcasters as regular carriers on the Web-888 panadapter. This is available without any action on the HQ-180.
Section 7 — Complete HQ-180 + Web-888 Dual-Role Station Architecture
┌──────────────────────────────────────────────────────────────────────────┐
│ HAMMARLUND HQ-180 + WEB-888 — COMPLETE DUAL-ROLE STATION ARCHITECTURE │
│ Receive-only — no T/R switching; safe at all times │
└──────────────────────────────────────────────────────────────────────────┘
─────────────────────────────────────────────────────────────────────────
ROLE 1: INTRABAND PANADAPTER (IF tap — follows HQ-180 VFO on amateur bands)
─────────────────────────────────────────────────────────────────────────
PRIMARY HF ANTENNA
│
[HQ-180 antenna input SO-239] → amateur bands only; safe at all times
│
[HQ-180 front-end and bandswitch]
│ (dual conversion on upper bands)
[HQ-180 455 kHz second IF] ──────── tap point ──────────────────────────┐
│ │
[HQ-180 detector → audio → speaker] [IF tap buffer PCB]
Primary audio: SSB, CW, AM on amateur bands 50 Ω BNC output
→ rear-panel BNC
│
─────────────────────────────────────────────────────────────────────────
ROLE 2: COVERAGE EXTENSION (dedicated antenna — full HF spectrum)
─────────────────────────────────────────────────────────────────────────
DEDICATED WEB-888 ANTENNA (1–3 m wire or small loop)
│ [No connection to HQ-180 primary antenna]
│ [Independent of HQ-180 operation]
│
└─────────────────────────────────────────────────────────────┐
│
───────────────────────────────────────────────────────────────────── │
WEB-888 SDR INPUT SELECTION: │
IF tap BNC ──────────────────────────────────────── Web-888 Input A │
Dedicated antenna ───────────────────────────────── Web-888 Input B │
OR: External BNC A/B switch between the two inputs if one-input SDR │
│
[Web-888 SDR] ── USB 3.0 → Computer ◄─┘
[OpenWebRX — two sets of profiles]:
ROLE 1 PROFILES (Input A: IF tap):
├── "80m — IF Tap" │ 455 kHz + 3.295 MHz offset │ LSB │ 500 kHz span
├── "40m — IF Tap" │ 455 kHz + 6.745 MHz offset │ LSB │ 500 kHz span
├── "20m — IF Tap" │ 455 kHz + 13.745 MHz offset│ USB │ 500 kHz span
├── "15m — IF Tap" │ 455 kHz + 20.745 MHz offset│ USB │ 500 kHz span
└── "10m — IF Tap" │ 455 kHz + 27.945 MHz offset│ USB │ 1.0 MHz span
ROLE 2 PROFILES (Input B: dedicated antenna — direct HF freq, no offset):
├── "160m" │ 1.900 MHz │ LSB │ 200 kHz
├── "49m" │ 6.050 MHz │ AM │ 300 kHz ← HQ-180 cannot tune here
├── "31m" │ 9.650 MHz │ AM │ 500 kHz ← HQ-180 cannot tune here
├── "30m" │ 10.125 MHz│ CW │ 100 kHz ← HQ-180 cannot tune here
├── "25m" │ 11.850 MHz│ AM │ 500 kHz ← HQ-180 cannot tune here
├── "WWV" │ 15.000 MHz│ AM │ 50 kHz ← propagation reference
├── "17m" │ 18.118 MHz│ USB │ 200 kHz ← HQ-180 cannot tune here
├── "12m" │ 24.940 MHz│ USB │ 150 kHz ← HQ-180 cannot tune here
└── "MW" │ 1.100 MHz │ AM │ 1.2 MHz ← HQ-180 cannot tune here
─────────────────────────────────────────────────────────────────────────
THE COVERAGE MAP — WHAT IS AND IS NOT COVERED BY EACH COMPONENT
─────────────────────────────────────────────────────────────────────────
HF SPECTRUM (0.5 – 30 MHz):
0.5──────1.8──2.0──3.4──4.0──6.9──7.5─9.4─9.9─11.6─12.1─13.7──14.5─
─────────────────────────────────────────────────────────────────────────
[HQ-180]: ████████████ ███████ ██████████
80m/75m 40m 20m
[Web-888 Ext]:████████████████████████████████████████████████████████
ALL OF THE ABOVE + ALL GAPS + ALL SW BROADCAST BANDS
14.5─15.1─15.8─17.5─17.9─18.0─18.2─20.9──────21.5─24.9─25.0─27.7─30.0
─────────────────────────────────────────────────────────────────────────
[HQ-180]: ██████████████████ ██████████████
15m 10m
[Web-888 Ext]:████████████████████████████████████████████████████████
ALL OF THE ABOVE + 19m/16m SW bands + 17m WARC + 12m WARC
HQ-180 + Web-888 combined: FULL COVERAGE with no gaps
HQ-180 alone: five amateur band segments; all other HF frequencies silent
Hammarlund HQ-180 + Web-888 dual-role station. The dual-input Web-888 configuration (IF tap for intraband + dedicated antenna for coverage extension) provides both roles simultaneously. Operators with a single-input Web-888 can achieve both roles via an external BNC A/B input selector switch. IF offset values shown are for mid-band frequencies; update the offset when tuning to a specific frequency within each band. All configurations are safe at all times because the HQ-180 has no transmitter. The coverage map diagram illustrates which HF segments each component covers; the Web-888’s coverage extension closes every gap in the HQ-180’s band-restricted design.
References and Notes
- Hammarlund Manufacturing Company, HQ-180 Instruction Manual. Primary reference for the HQ-180’s frequency coverage, band-switch positions, IF architecture (dual conversion on upper bands), and the 455 kHz second IF circuit. The service manual’s circuit diagram and chassis layout identify the second IF section components used to locate the tap point. HQ-180 variants (HQ-180A and related) have some circuit differences; confirm the service manual edition matches the specific unit. Available through the vk6ada.com.au Hammarlund resource archive.
- Mike Peace VK6ADA, Hammarlund HQ-180 Failure Prevention Kit, vk6ada.com.au. The comprehensive HQ-180 failure mode reference, covering the electrolytic capacitor priorities, front-end tube types, bandswitch contact maintenance, and VFO stability characteristics. The internal chassis access cautions in Section 3 of this guide are consistent with the FPK’s guidance on the HQ-180’s supply voltages. Operators who have not recently reviewed the HQ-180 FPK should do so before undertaking IF tap installation.
- Mike Peace VK6ADA, Web-888 SDR with the Hammarlund SP-600 SWL Station, vk6ada.com.au (March 2026). The companion SWL guide for the SP-600, which covers the IF tap methodology, OpenWebRX configuration for a general-coverage receiver, and the fourteen ITU SW broadcast band profiles that form the basis for the HQ-180 coverage extension profiles in this guide. The SP-600 guide’s broadcast band profile table is the reference for the Role 2 profiles in the HQ-180 integration.
- Mike Peace VK6ADA, Web-888 SDR with the Collins R-388/URR SWL Station, vk6ada.com.au (March 2026). The companion professional receiver SWL guide, providing the IF tap installation methodology, IF offset formula, and OpenWebRX dual-band profile structure that the HQ-180 guide adapts for the amateur-band-only receiver context. The R-388 guide’s comparison of Collins PTO vs other VFO architectures is the reference for understanding why the HQ-180’s VFO tuning produces a different panadapter integration experience from the R-388’s PTO system.
- Mike Peace VK6ADA, RX-888 Mk II with the Collins R-390A — Practical Cascade Integration via the CASCADE-390 IF Tap Kit, vk6ada.com.au (March 2026). The foundational IF tap methodology guide. All IF tap integration principles (buffer design, 455 kHz configuration, OpenWebRX offset calculation) apply directly to the HQ-180 integration. The HQ-180’s 455 kHz second IF is consistent with the CASCADE-390 approach; the buffer PCB designed for the R-390A family applies with HQ-180-specific chassis mounting and tap point adaptations documented in the HQ-180 kit notes available from vk6ada.com.au.
- IARU Region 2 and Region 3 Band Plans; ITU frequency allocation table for the HF amateur service. References for the amateur band frequency boundaries used in the HQ-180 coverage map in the circuit legend and the IF tap profile frequency ranges in Section 5. The WARC bands (30m, 17m, 12m) are included in the Web-888 Role 2 coverage extension profiles because they are fully accessible to licensed amateur operators in most jurisdictions and are not covered by the HQ-180’s design. Available at iaru.org.