N9EWO Review :
Lowe HF-250
 HF Communications Receiver
(including HF-225 comments)


The discontinued and rare "Lowe HF-250 HF Communications Receiver" from the mid-late 1990's.
  Tested was a stock "Non Europa" version, plus a second sample with PROPERLY slightly modified
 narrower IF filters (see text and chart below). Simply one of the best tabletop HF receivers for
audio quality and overall AGC performance EVER MADE especially with the optional DU-250 Sync board installed.
 Even tops the AOR AR7030 for audio quality in our view / testing (with the PROPER 2 way external speaker). (N9EWO Photo)


Discontinued Receiver

COUNTRY OF MANUFACTURE: United Kingdom

Approx. Serial Number on the 2 test samples :
#1 :  4531xx (Manufactured in 1995) Firmware Ver 1.1
#2 :  4607xx (Manufactured in 1996) Firmware Ver 1.3
(Note : Previously tested a 1993 made HF-225 "stock" version and will see references to this below. Serial No. : 3014x)

Options Tested:
- DU-250 Synchronous Detection Board / FM Unit (#1 and #2)
- WA-250 Whip Amplifier (#1)
- RC-250 IR Remote Control (#1 and #2, as shown in above photo)

Antennas used in testing:
- Comet (Japan) H-422 dipole (34 ft long)
- RF Systems MLB "Long Wire" (55 ft long)

Regulated Linear "Transformer Type" 12 VDC Power Supplies tested with the HF-250 :
- Astron RS-7A (voltage set at 12.0 volts, internal adjustment), proper cable and *plug made.
- Jameco 170245 (DDU120100H4480) 1 Amp (* with DC plug change, nominal voltage is approx 12.5 volts)
(* - Philmore # 210L, plug must have longer length due to rear cabinet thickness)

PRO :
- One of the BEST HF / SW Receivers EVER TESTED for audio quality including ultra LOW distortion with DU-250 in use (see con).
- Audio amplifier / radio circuits are totally hiss free and plenty of output to drive most small efficient hi-fi speakers.
- Single tone control that is very effective.
- Excellent sensitivity and low noise floor.
- Very Good Dynamic Range (see text).
- DU-250 Synchronous Detector / FM Board that works well and features selectable sideband (see con) [optional, was included with Europa version ?].
- LED Backlit (down to 100 Hz) LCD Frequency Display that is easy to see / read (much improved over the HF-225/235 models).
- Accurate S-Meter that is nicely lit by 2 or 3 LED's depending on production (see text).
- SIX excellent "Front End" Filters that are also housed in a metal can shield (filters totally lacking in the AR7030).
- Respectable "Dynamic Range" with even longer wire antenna's in use (USA Midwest). [optional WA-250 whip amplifier should not be used with external antenna's]
- Four (Five if you include the one in the DU-250) properly chosen Bandwidth Filters [11, 6 and 4 element Murata ceramic filters are used].
- 255 Memory Channels that store Frequency, Mode, Bandwidth Filter and Attenuator settings.
- Memory Channels use EEPROM storage (are NOT battery backed unlike with the HF-225 or HF-235 models).
- Bourns silky smooth "Ball Bearing" OPTICAL encoder used for "Main Tuning" solid metal knob (see con).
- Adequate OK stability (see con).
- 2 VFO's (see con).
- All push buttons have excellent tactile feedback [just as with earlier Lowe sets and the AR7030].
- Very good above average AGC (see con).
- Electronic selection of mode (see con).
- RC-250 IR Remote Control Option that also adds Direct Frequency Entry (see con), [was included with the Europa version as stock ?].
- Single Step 20 db attenuator (is also switched from front panel).
- Extremely Clean rear mounted "Line Audio Output" Jack that is also at the proper level.
- 24 Hour Clock that displays seconds.
- 2 Built in Timers.
- Rear AUDIO Mute Terminals as well as a MUTE function on optional RC250 remote.
- ALL Metal robust case and knobs that also use set screws (except for plastic around speaker / handle opening area).
- Built in RS-232 interface (9-pin) (see con).
- Low Current Consumption (as far as communications receivers go).
- One of the coolest operating communications receivers ever tested [cold operation even after hours on].
- Has held up better in it's old age over the AOR AR7030 and in some ways performs better (see AR7030 review here).

CON :
- Steep Price Tag (when new or used market).
- Some will call the HF-250 a ergonomic nightmare with minimal number of pushbuttons and controls.
- Single AGC is a bit SLOW (no faster selection offered).
- No RF Gain adjustment.
- VFO's do not store Mode or Bandwidth settings.
- No TCXO (Temperature Compensated Crystal Oscillator) Reference (TCXO option was never offered, the HF-235 was the only Lowe set that did).
- Quirky and painful mode selection scheme.
- Finicky VRIT (Variable Rate) 2 Speed Tuning System with tuning knob is frustrating.
- Fast Frequency Step Button (1 kHz) does not lock which make this feature much less useful (a 2 handed affair to use).
- DU-250 Synchronous Detector Option while very good, is not as solid locking as the Sony ICF-2010 (ICF-2001D). Certain weak signals or with deep fading do not always fare well. MUST be tuned in center of a signal for best lock (that range is very limited).
- RC-250 IR Remote Control uses non-standard numeric keypad layout and lacks Volume Control adjustment.
- RC-250 IR remote sensor is located behind the S-Meter (low end) which makes for difficult use if pointed at too low of an angle.
- RC-250 uses some off beat IR code (see text).   
- Top internal speaker is a disaster [a good 2 way EFFICIENT external speaker is REQUIRED, see text]
- With firmware 1.1 (sample #1) receiver "locked up" frequently requiring to reapply power. Firmware 1.3 (sample # 2) cleared up most lockup issues. (see text)
- S-Meter digits are near impossible to see with # 1 test sample. This issue was fixed with later production as experienced with # 2 sample (see text and photo).
- Tuning Knob can migrate (move) off of last tuned position with any vibration's near the cabinet or sometimes even with button presses on the set (will make the knob rotate, see text).
- Uses a internal soldered in Lithium Button cell for Clock backup. This is NOT required for operation and in fact best to just CAREFULLY remove and leave it out entirely to rule out any leaking issues.
- As with ALL Lowe receivers and the AOR AR7030, the rear antenna switch is prone to become intermittent in time (gets dirty). easily fixed for most owners (Deoxit D5).
- RS232 computer interface is near useless as no official after-market software was ever released. Lowe had some DOS based software (not tested), but is not usable with modern computers.
- SL6440 mixer IC's very prone to ESD damage [ALWAYS TOTALLY and physically disconnect outdoor antenna's when not being used].
- Service Information Impossible to obtain (if it was ever released at all ?) WARNING : The close cousin HF-225's service information is NOT valid for the HF-250 ! The HF-250 never had a officially released service manual.

N9EWO Review : Lowe HF-250 Communications Receiver  (Standard Version)

First a quick look at the HF-225 / Main Encoder / Memory Battery

The previous Lowe models before the HF-250 were the HF-125 (that started it all for the John Thorpe receiver designs) and the improved later HF-225, along with the lower cost HF-150 model later. Tested
previously was a stock version of the HF-225 and a number of general quirks come to mind immediately, as good as the HF-225 was.

First the HF-225's "Alps" main tuning" control was not only very restrictive / hard to turn even when brand new (unless the encoder bearing grease is/was removed and is NOT recommended) but it was was only a mechanical type of encoder. So was prone to become dirty and "skippy" (ditto for the standard version of the AOR AR7030).

The very limited HF-225's 30 memory channels do not store mode and were backed by a internally "soldered in " lithium battery. WARNING: By now all of these batteries have become dead (or are near dead) and are prone to leaking/corrosion damage if not CAREFULLY taken care of. I say properly taken care of as if not replaced or removed without care as it has been said elsewhere the 5101P IC connected with memory operation is very prone to ESD (Electro Static Discharge) damage and is not easily repairable anymore. 

"The HF-225's 5101P RAM IC is EXTREMELY sensitive to ESD and is easily destroyed even by a non ESD soldering iron. When removing the discharged lithium cell great care MUST be taken to protect the chip from ESD and transient voltages. One should NOT use other battery systems say using 2 AA batteries in a holder. One will probably kill the chip when fitting your battery holder or inserting the batteries into it. The proper PCB mounted lithium cell (with solder tabs) is the ONLY recommended replacement for the original, nothing more exotic or modified."
.

I will NOT be held responsible for any info that is listed here
ALL DONE AT YOUR OWN RISK !

Basic receiver design of the HF-250 is very similar to the earlier HF-225 but not entirely. For example : There were improvements made in the first mixer section as well as different values for the two heterodyne oscillator adjustments. The HF-250 uses a different 11.520 MHz reference oscillator frequency. Please don't ask me what the different adjustments values are as I do not have them. If you have SOLID proper HF-250 "het" values (as used in the TEST mode) please send a email so this important information can be added here.

WARNING : Do NOT use the HF-225 service information for the HF-250.


The Lowe HF-225
 (with it's weak "2 Green LED" LCD Backlight) (John B. Photo)


The HF-225's LCD backlight brightness was another bug. It was just not bright enough to easily see, more so for anyone with limited vision. Some handy owners have modified the two green backlight LED's to improve on this, but not everyone are electronic savvy.

John Thorpe the designer of the Lowe HF series sets (up to the HF-250), was not with Lowe when the actual release of the HF-250 came onto the market as by then he had well moved on before to work for AOR UK and designed the AOR AR7030. Completion of the HF-250 to a working and marketable product was reported to be engineer Kevin Whitehead at Lowe's and Richard Alton (Zycomm) who wrote the software (firmware).

Actually for awhile the HF-250 and AR7030 were in direct competition with each other. The HF-250 was only manufactured for around 3~4 years from early 1995 to 1998~9 (Europa version only from Dec 1996), so not huge numbers for used samples in the market place. More exist in it's standard version and fewer with the later Europa version. Either model were a poky seller with its steep retail price tag and with the new kid in the block AR7030 slurped up most of the sales with it's similar pricing and added features.

As covered in the report below, the bugs above were addressed and improved with the HF-250 over previous Lowe models. In some ways it was actually was better over the AR7030 including holding up better with age
. See N9EWO's AOR AR7030 review here. .

IF Filter

Murata Filter

Specs. (kHz)
 Sherwood
 Test (kHz)
X2
CFJ455K14
2.2
2.3
X3 CFW455HT
6.0
8.8
X4
CFW455IT
4.0
5.6
X5
CFU455G2
9.0
10.9
X6
(SSB Carrier
Insertion Filter)

CFW455IT
4.0
5.6
X1
(on D-225
Sync Board)
CFU455F2
12.0
13.0~14.0
(est only)
Murata ceramic IF bandwidth filters as used in the Lowe HF-225 Receiver (Standard Version).
Sherwood Engineering HF-225 1994 testing. Of course the HF-250 uses the same filter scheme, see text/review. (N9EWO Chart)

HF-250 Size / Weight / Excellent Anodized Metal Case

The Lowe HF-250 is housed in a very attractive and robust cabinet with the sides, front and back being made out of anodized aluminum (top and bottom are metal painted). All 3 front panel knobs are also aluminum metal and make use of set screws (no push on ones to be found on this radio). Also the bottom cover attaches to the shell using 4 machine screws that insert into the cabinet that are using real threaded inserted nuts. It's not just using threaded taps going into a suboptimal soft die cast metal that the AOR AR7030 uses (which commonly strip out).

Tip : To enter the HF-250's cabinet (at your own risk of course) one removes the 3 knob set screws (Volume-Tone-Main Tuning Knob). Then remove the 2 large "Hex" screws at each end on the FRONT panel. The front panel then can be removed, then the interlocked piece on the top panel can also be removed along with it's internal speaker and access to the PC boards. Do NOT remove the rear panel. IMPORTANT : Bottom cover removal has just 4 screws, but be careful as with one of our test samples there were plastic (nylon) washers in between the cabinet and rear cover screws that can be very easily lost.
 

Cabinet Size and Weight Comparisons (no options)      SIZE  Inches 
   W  X  H  x D   (mm)    

WEIGHT Lbs (kg)
LOWE HF-250
11.02  x 4.13 x 8.07
(280 x 105 x 205)

6.0
(2.8)

LOWE HF-125 / 225
10.0  x 4.0  x 8.3
(253 x 109 x 204)

4.2
(1.9)

LOWE HF-150
7.2 x 3.2  x 6.3
(185 x  80  x 175)

  3.0
 (1.3)

AOR AR7030
9.4 x 3.7 x 7.51
(238 x 93 x 191)

4.9
(2.2)

Buttons / Main Tuning Encoder / Lock Function / 2 VFO's

Seven momentary push buttons populate the front panel for all of the receivers operations. These are of the same type as used with other Lowe receivers (and the AOR AR7030) and have a excellent tactile feel along with have generally better reliability over tac or carbon contact pad buttons in time. They also have dual and triple functions but this was logically designed so not a negative here.  

The Lowe HF-250 makes use of a OPTICAL "ball bearing" encoder for the main tuning (knob). Made by Bourns, part number : ENS1J-B28-L00256-256PPR. It is as silky smooth as it can get and most welcomed vs. the low cost mechanical Alps tuning encoders as used in all other Lowe receivers before the HF-250 (plus standard version of the AOR AR7030) that could (or do) become problematic in time.

One "bug-a-boo" with this, the knob is very sensitive to any vibrations around the cabinet (it can move / tune off frequency). One can almost tune it by just blowing on the knob. But this is still far better than the low cost encoder used on the HF-150 or 225 / 235’s. One could perhaps put a very thin piece of round felt (cut like a washer) behind this knob to help on this (not tested) ? There is also a lock function that will help here as well. It is activated by pressing and holding the FN / Memory button along with the MHz DOWN (FN + Mhz UP button to turn it off). No indication on the LCD that informs you if the lock is on or not (not a biggie here).

Tip : If one experiences backlash with the main tuning knob (that is the knob moves after you let go of it), flip the set over and remove and replace the knob on a hard FLAT surface (of course protecting the cabinet with proper padding). The main tuning knob uses a  2.0 mm hex key wrench. NOTE : This may take a number of attempts to reduce or eliminate this trait. It has to do with the solid metal knob being ever so slightly crooked in mounting and throwing it's balance off. Check to be sure that the knob is set out far enough so not to scrape the front panel (but not too far out either). This is a bit of a trick to do properly (take your time).

TWO VFO are provided and appreciated. These are a bit of a chore to make happen using a function button (press and hold the MEMORY and FILTER button) but works and even the Icom IC-R8600 receiver lacks TWO VFO's. Downside is that the VFO's do NOT store mode or filter settings (a silly oversight).

I will NOT be held responsible for any info that is listed here
ALL DONE AT YOUR OWN RISK !

Excellent Front End Filtering

The Lowe HF-250 (as with the HF-225/235) uses "Six" RF input tuning filters in the front end. These are also surrounded by a "metal" shield. This proper filtering is totally lacking in the Lowe HF-150 and even with the AOR AR-7030.  No worries with any local MW or FM broadcast signals bleeding into the HF-250 (no external filtering devices required) !

 LOWE HF-250 RF Input Tuning Filters
1.  Below 500 kHz
2.  500 kHz to 1.7 MHz
3.  1.7 MHz to 4.2 MHz
4.  4.2 MHz to 11.0 MHz
5.  11.0 MHz to 19.0 MHz
6.  19.0 MHz to 30.0 MHz

Decent Dynamic Range (overload in testing with VERY STRONG LOCAL Amateur Signals)

Signal overloading was never really an issue with the HF-250. Even with hot "nighttime" band conditions band conditions in the 49 meter band with a decent long wire antenna we never detected it being swamped with broadcast listening.

The ONLY "Dynamic Range" issue was with very local and super strong amateur radio signals. This overloading appeared as a whistle mixed in along with a reduction in the desired signal than the normal mishmash mess of spurious junk sounds.


Mind you this issue will not be deal breaker for most and is of little concern (but for the record),

Low Current Consumption / Power Supply / Cool Operation / No TCXO used


With the HF-250's low current consumption (as far as communications receivers go), makes for a good candidate for field portable / battery use. As you can see in the chart below, it does consume about 100 mA more than the HF-225, but this makes total sense with the more advanced microprocessor operation including electronic mode selection and brighter LCD backlight etc.

One should ONLY use a 12 volt REGULATED DC power supply with the HF-250 (and Lowe HF-150/225 receivers). Of course avoid ALL switching type power supplies as they will near guarantee generated noises across the HF radio frequencies. The Jameco 170245 12 volt regulated linear supply was tested with both test samples of the HF-250's (as well as the HF-225) and have adequate current and remains on the cooler side. Last 170245 adapters purchased (2016) were still of a 100% linear design and super RF quiet. Keep in mind that Jameco has been in the SNEAKY process of changing over to the use of HF NOISY switching REGULATORS in the "Reliapro" AC Adapter line over the years without any indication of such a change (first hand experience on this so you have been warned). NOTE : Jameco still call these changes with the effected adapters linear as they still use a power transformer. The move to switching regulators was obliviously done to reduce production costs (can use a much smaller regulator heatsink with less heat produced).

IMPORTANT : One will have to be handy with a soldering iron to make a change with the DC plug on the 170245 Jameco adapter as it takes a longer length shaft plug to work with the HF-250 (positive tip). Philmore # 210L has the exact proper plug size and length (see chart below for required specifications).

Also tested with a larger "Transformer-Linear-Regulated" Astron RS-7A power supply. Here the rear heat was only very mildly warm even after hours of use.

Speaking of cool operation, even for hours on end the HF-250 produces so little heat as to say its cold and stays that way (dependent on room temperature). It and the HF-225 are the most "cool" operating communications receivers we have ever used PERIOD. This is great news for longevity as ANY generated heat in a receiver cabinet is the number one killer of electronics (including electrolytic capacitors).

Just as with the HF-125, HF-150 and HF-225, the HF-250's "11.520 MHz" Reference Oscillator is not using a TCXO (
Temperature Compensated Crystal Oscillator). Mind you the HF-250 is more than stable enough, however MAJOR room temperature swings (say Air Conditioning in the summer months) can make for very slight reference oscillator differences and display errors. This is usually limited to well under 10 hz which is still decent and well within specifications. 

Improved LCD / Backlighting / MODE Selection

Lowe made major improvements with the HF-250's "negative type" LCD display when compared to earlier models. First the display now goes down to 100 hz accuracy. This is the only Lowe "DESIGNED" receiver to ever offer this. Next the backlighting was made more even and with proper brightness. With a HF-225 or HF235 one can just barley see it. For user with less than stellar vision could be even worse to make out the frequency and sync lock status.

Mode selection is electronic and is also stored in the memory channel data. 6 bright separate LED's are used for mode indicators. However it is using a dreaded carousel arrangement. To make matters even worse takes a pushbutton of the mode button, then while the mode LED(s) are flashing one uses the up down buttons to select the mode and finally a another press of the mode button again to get back to normal operation. WHEW !....this exercise is a bit less tedious after awhile, but is not ergonomically friendly.

MODES (independent of bandwidth filtering, more on this later) :      
- CW (which also includes a selectable 200 hz audio filter)
- LSB
- USB
- NFM (Narrow Band FM, with DU-250 option installed)
- AMS (Double Sideband Sync, with DU-250 option installed)
- AMS LSB Sync (with DU-250 option installed)
- AMS USB Sync (with DU-250 sync installed)
- AM Standard

Tuning Steps - Fast Button / Finicky VRIT / Not a Good "Band Scanning" Receiver

Tuning the HF-250 with the main tuning knob can be a disconcerting exercise. There are two speeds but are ONLY selected on how fast you spin the knob, Rotating the knob slowly gives for a very poky 8 hz tuning step. Give it a faster spin and kicks in a faster 1 kHz step which is the best for band scanning. The annoying trick here is learning on where the kick in point is between the 2 speeds. One should adjust to the scheme with some use (well we hope anyway) ? There is FAST pushbutton on the front panel where you are able access the faster 1 kHz step without the fast spin of the knob, however the button is only of a intermittent type (it can't lock) which is pity as it makes for more difficult 2 handed tuning.

When the Sync mode is in use (DU-250 board installed) when the knob is rotated quickly the Sync will automatically revert to standard AM mode for easier tuning and will switch back to Sync when tuned on a frequency (takes about a second). This is a very useful feature.
 
Other Misc. LOWE HF-250 Information
 PROPER DC Plug Size :
2.1 mm ID x 5.5 mm OD (long length shaft)
[Philmore # 210L, 1.45 inch shaft length]
[longer length required due to rear cabinet thickness]
Hex Key Cabinet Screw Sizes :
Volume and Tone Knobs : 1.5 mm
Main Tuning Knob : 2.0 mm
Front Panel : 3.0 mm


Rear View of the Lowe HF-250.
REGULATED 12 VDC Power input REQUIRES a long shaft 2.1mm ID x 5.5 mm OD power plug.


Firmware 1.1 and 1.3

We do not have available a list of improvements with firmware versions (what Lowe called software). With test sample #1 that used 1.1 firmware, frequent total lockups of operation was experienced. This was more of a issue when changing modes or dealing with memory channels. The only way to restore normal operation is to totally power down the receiver.

With the later firmware 1.3 on test sample 2, these lockup issues were nearly eliminated. Have to say almost as one time (and only one time) in testing "lock up" did also occur. This was lock up was while in Memory mode. From our gathered information there was one more firmware standard version above 1.3 (1.4 not tested) and the lone 1.5 was for the Europa version (not tested). The "software" version is displayed for a second at power up.


Excellent Accurate Mechanical S-Meter

The HF-250 features a excellent real mechanical signal strength meter. Even being on the tiny side, it is most accurate and never pinning out in testing. Very close readings when compared to the Icom IC-R8600 digital meter (S-Unit selection). With earlier production samples the same identical meter was used in the Lowe HF-125, HF-225 and HF-235 models. Uses 2 top mounted LED's to light it up. This was a bit inadequate as it was dim and hard to see. Lowe made an improvement here as the #2 test sample uses 3 LED's for the S-meter lighting. Mind you it's still lacks a bit here for meter lighting, but is a definite improvement.

Also changed with mid-late production were the printed S-Meter markings that were made much larger and much easier to see (photo below).      



Lowe made two changes with the S-Meter on later samples. For early production they used
the same meter as in the HF-225 with the small printing. Later they improved the meter
with larger numbers and also added a third LED to help light up the area better
 (originally it was just 2 LED's). (N9EWO picture edit)


RC250 IR Remote Control / 255 Non-Volatile Memory Channels

Optional (expect for Europa version) RC250 Wireless IR Remote control was tested with both samples. It is the only way to accomplish direct frequency entry. The keyboard layout is not numerically friendly. Changing modes is still the same chore as done directly on the set. There is a STDBY button which works with the timer mode but also allows for a "defacto" on and off function.
Even it there is no volume level control, a MUTE button is found on the remote which is most useful. This is function is not found on the front of the set. A wired MUTE connection can be found on the rear panel.

WARNING : MUTE is of a audio type only and does NOT disable any RF stages. 

The IR "receive" sensor on the cabinet is strangely located (hidden) BEHIND on the lower part of the S-Meter. One needs to properly point the remote high enough otherwise it's nada. Otherwise the IR range is more than adequate. RC-250 requires 2 AAA batteries and rechargeable types work just fine (recommended).

IR code used was for a Nokia Satellitte receiver and is NOT covered with any of the universal type remotes. If you wish to use a Universal type remote it will have to be of a learning type with enough memory (and of course a original RC250 remote). A older model Sony RM-VL600 was tested with good results. This allows for much easier direct keyboard entry.     

Tip :
Audio mute function (on remote or direct rear connections) operates while in "VFO mode" only. If attempted in memory mode only the memory channel number appears for a second (mute not functioning.). Ditto for making any mode changes (you MUST switch into the VFO mode first).

255 memory channels are available and also store the MODE, FILTER, ATTenuator settings. Most importantly these do not require a battery to retain data (uses EEPROM). The lone lithium cell is ONLY used for clock backup when the DC power has been disconnected from the receiver (original batteries dead in used samples now). One can cycle through the memory channels using the tuning knob which is a very nice touch as well as being able to directly enter (go to) the memory channel.

I will NOT be held responsible for any info that is listed here
ALL DONE AT YOUR OWN RISK !
 Internal LM2430 (CR2430) Lithium "Clock" Battery
The Lowe HF-250 uses one LM2430 (CR2430) lithium button cell (soldered in place with vertical tabs) for clock "counting" and retaining clock timer settings when "totally" disconnected from DC power. It is NOT required (unlike with the HF 125/225/235 models) for memory data storage. The HF-250 uses a EEPROM just like with the HF150.

By now most of these "clock" batteries have died and are prone to leakage and possible PC board damage. So it's not a bad idea to just remove this now dead battery entirely and just not replace it (so not have to worry about it ever again). One will have to set the clock and timer setting every time the HF-250 receives DC power which is no big deal. If one attempts to remove this battery be sure and follow ALL ESD protection procedures ! We found it was easy to just VERY CAREFULLY clip (cut) the battery out using a GOOD pair of small "Nippy" cutters (receiver not connected to ANY power of course). No soldering iron required. See photo below.

IMPORTANT NOTE (without a 2430 battery installed): Every time power is applied to the receiver via the rear jack one must clear out the erroneous clock/timer data that appears at power up. Of course you will need to set the clock anyway. But normally timer 1 is toggled on and both timer 1 and 2 are loaded with weird number entries. Just clear these out (set them) and all is well. This is NOT a malfunction of the receiver in anyway here. See page 27 in the owners manual for clock / timer setting instructions.


Lowe HF-250 Internal Photo (with the DU-250 installed). Shows the location of the LM2430 lithium "Clock" backup battery.
 It is NOT required for Memory Retention (unlike with the HF 125/225/235 models). It is a soldered in battery. (Randy M. Photo)
 
LOWE HF-250 / HF-225
**** N9EWO Current Consumption Testing ***
Tested Current Consumption at 12.5 Volts   Meter: Fluke 77 IV   f: 7490 kHz
(volume control set at normal level)

***** LOWE HF-250 Test *****
- AM Sync ON : 340 ma PEAK
- AM (Sync OFF) - SSB / FM : 305 ma PEAK
- CW : 320 ma PEAK

***** LOWE HF-225 Test *****
- AM Sync ON : 240 ma PEAK
- AM (Sync OFF) - SSB / FM : 215 ma PEAK
- CW : 225 ma PEAK
Actual current testing between the HF-250 and the HF-225. The HF-250 using about 100 ma more current
 which makes total sense with it's brighter LED display backlighting / microprocessor mode selection
 - LED indicator plus additional microprocessor functions including non-volatile EEPROM memory. (N9EWO Chart)


Sensitivity / Selectivity / Excellent Image Rejection / Built in Noise Blanker

Sensitivity is equal to any other properly operating HF receiver.

IMPORTANT : The now very rare SL6440 mixer IC's are very prone to ESD damage. So ALWAYS TOTALLY and physically disconnect outdoor antenna's when not being used (don't count on even grounded antenna switches). Many used HF-225 and HF-250's sold today have blown or partially blown SL6440's due to misuse (as well as blown didoes in the front end filter section). Please keep this in mind when shopping for a used sample.

A built in noise blanker provided by the SL6700 integrated circuit works brilliantly (thank goodness as it cannot be turned off). PLEASE NOTE : ALL HF-225 / HF-235 and HF-250 schematics have this IC part shown as the SL9700 which is WRONG !

All IF bandwidths with it's 5 included filters are totally independent of mode (the way it should be, see chart below). Image rejection is just excellent. Just as with the AOR AR7030, a few bridies are noticed in a few places, but most are covered when a decent antenna is connected. A 200 hz audio filter is available in the CW mode.

 Standard
Lowe HF-250
  Filter Selection
 As Stock
 (Murata)
Real -6db
Bandwidth
 (Sherwood
 Engineering
 1996 Testing)
 #2 Sample Modified
 Bandwidth
 Filters
(marked bandwidth) 
Real Bandwidth
 (sounds like)
X2 (2.2 kHz)
 CFJ455K14    
2.5 kHz
  
CFJ455K14 
  (no change)

2.5 kHz

X3 (6 kHz)

 CFW455HT
6.7 kHz
   NTK LF-H2S    
 (4 kHz)
5.5 kHz

X4 (4 kHz)

   CFW455IT
5.7 kHz
NTK LF-H2S
(4 kHz)
4 kHz

X5 (9 kHz)

   CFU455G2
10.7 kHz
CFU455H
(6 kHz)
7.5 kHz
X6 (4 kHz)
SSB Carrier
Injection Filter
  CFW455IT
5.7 kHz
CFW455HT
(6 kHz)
N/A
X7 (12 kHz)
DU-250 SYNC
Filter
(bypasses X5 tail filter
 when ONLY used)
CFU455F2
 13 ~ 14 kHz
(estimate)

LTV455G
(9 kHz)
 

11 kHz
(estimate)
 (N9EWO chart)

Test sample #1 was stock (no modifications) and with firmware 1.1. Test Sample #2  (firmware 1.3) contained narrower ceramic bandwidth filters for X3, X4,  X5, X6 and X7 that were carefully chosen and professionally done (similar to the very limited HF-225's "Finlandia" version ?). As you can see the modified X3 and X4 filters are of the same value/type. But when both are selected (X4- 4 kHz) gives for improved skirt selectivity, so be it a bit narrower bandwidth/sound compared to only when X3 is used (5.5 kHz). A HUGE plus over the untested Europa version here is with filter X7 on the DU-250 Synchronous Detector board was also SLIGHTLY narrowed which improved "sync lock" over the #1 test sample using the 10 kHz filter selection in Sync mode. Overall these filter changes improved DX performance in testing. Interesting part with the "sample 2 filter" changes as listed above (from viewing PC board soldering), these appeared to have been installed at the time of manufacture. Lab numbers courtesy Sherwood Engineering. (N9EWO chart)

 WARNING : One needs to be aware that soldering work with ANY LOWE receiver must be done extremely carefully and with the right equipment as it's very sensitive "plated through" PC board holes are very
susceptible to heat damage (ditto for the AOR AR7030) ! To make matters even worse (according to Pete Gianakopoulos) the PC board hole sizes are very tight with most components. Any work like this is best left to a professional. Obtaining the PROPER filters is another huge problem as all have been out of production for some time.

I will NOT be held responsible for any info that is listed here
ALL DONE AT YOUR OWN RISK !

Superb Audio Quality / Super LOW Audio Distortion / Proper External Speaker a MUST  / Line Out Jack

Audio quality with the two tested Lowe HF-250 samples has to be one of the lowest HF receivers for audio distortion that has ever been tested (portable or desktop, AM signals with the DU-250 Sync board installed). It has a very open sound that just is extremely pleasing to the ears including decent lower end frequency response. It's superb AGC also contributes to the end product that irks out of the speaker. The single AGC decay rate is on the slow side but the single value chosen is good.  We did not have a AOR AR7030 on hand to do side by side testing here, however the HF-250 just appears to have the edge at lest by a hair. See the chart below to view Sherwood engineering test data with audio distortion.

The single tone control is very effective to adjust the high end or low end speaker audio. However cannot provide the really deep bass audio response that the ICOM IC-R8600 can give with it's excellent Bass and Treble controls. The Lowe HF-250 is cleaner sounding with less overall distortion.

However to archive this stellar clean audio one MUST use the proper EXTERNAL speaker. The top mounted internal speaker (it's opening is integrated with a very unique carrying handle) greatly disappoints and use of a proper external speaker is required. Our favorite classic Realistic Minimus 77 Hi-Fi 2-way speaker speaker works extremely well (as did the smaller Minimus 7 model) with the HF-250. ALL other 2 way die-cast hi-fi speakers tested were grossly inefficient for use with extremely low power audio amplifiers. This includes most later Optimus and RCA models also sold by RadioShack (as tested).

Rear mounted 1/8 phone jack is provided for LINE OUTPUT. Even if not buffered independently (small "op-amp" audio amplifier) it's extremely clean and has proper output level.

 AUDIO    
 DISTORTION 
 Sherwood
 Engineering Data

 LOWE HF-250
 AOR AR-7030  Eton / Grundig E1
 ICOM IC-R8600 (Firmware : 1.32)
 AM 100 hz Narrow Bandwidth : 1%
Wide Bandwidth :    1%
5 kHz Bandwidth : 3%
4%
 Not Available
 AM 200 hz
Narrow Bandwidth : 1%
Wide Bandwidth :  0.7%
5 kHz Bandwidth : 2%
2%
 Not Available
 AM 400 hz
Narrow Bandwidth : 1%
Wide Bandwidth :  0.5%
5 kHz Bandwidth : 1%
2%
 Not Available
 AM 1000 hz
Narrow Bandwidth : 2%
Wide Bandwidth :  1.0%
5 kHz Bandwidth : 1%
2%
 Not Available
 AM 2000 hz
Narrow Bandwidth : 5%
Wide Bandwidth : 1.5%
5 kHz Bandwidth : 1%
2%
 Not Available
 AM Sync 100 hz
Narrow Bandwidth : 2%
Wide Bandwidth :    2%
5 kHz Bandwidth : 3%
3.5%
 Not Available
 AM Sync 200 hz
Narrow Bandwidth : 1%
Wide Bandwidth :    1%
5 kHz Bandwidth : 1.5%
1.5%
 Not Available
 AM Sync 400 hz
Narrow Bandwidth : 0.5%
Wide Bandwidth :    0.5%
5 kHz Bandwidth : 1% 2.7%
 Not Available
 AM Sync 1000 hz
Narrow Bandwidth : 0.5%
Wide Bandwidth :    0.5%
5 kHz Bandwidth : 1%
2.7%
 Not Available
 AM Sync 2000 hz
Narrow Bandwidth :   ?
Wide Bandwidth :    0.3%
5 kHz Bandwidth : 1%
2.7%
 Not Available
 SSB 100 hz
3%
(noise) 1%
1.5%
 Not Available
 SSB 200 hz
1.5%
(noise) 1%
1%
 Not Available
 SSB 400 hz
0.3%
0.3%
0.7%
 Not Available
 SSB 1000 hz
0.1%
0.2%
1.5%
 Not Available
 SSB 2000 hz
0.1%
0.1%
3%
 Not Available
notes : AM tests - 60% modulation
Sherwood Engineering "Audio Distortion" Test Data with the Lowe HF-250, AOR AR7030 and Eton/Grundig E1.
The Lowe HF-250's overall audio distortion is one of the lowest to be found on a SW receiver (portable or tabletop).
Lab numbers courtesy Sherwood Engineering (Icom IC-R8600 audio distortion testing to be added at a later date ?). (N9EWO Chart)

DU-250 Synchronous Detector / FM Board


DU-250 Synchronous Detector board option is a near requirement for the HF-250. It was a optional "soldered in" accessory board except for the later Europa version (not tested). Unlike the D-225 Synchronous Detector board in the HF-225, the DU-250 has "selectable sideband" sync available which allows for improved interference rejection. A handy green AMS LOCK LED is provided, however even if it does not lite does not mean it is totally out of lock.

As it is very common with HF-250's with the DU-250, one will usually find the LSB AMS selection to sound a bit sharper vs. USB AMS. This bug can actually be a huge advantage as can give for uncanny excellent audio recovery on weak signals even with narrower bandwidth's in use.

One needs to have the lock point of the detector in the middle of a carrier for proper operation. However in practice we found just slightly RIGHT of carrier center for the best audio. It does not lock as well as say the classic Sony ICF-2010 / 2001D
Synchronous Detector as (rarely) it can drop out slightly with very deep fading signals even on strong signals. But overall the HF-250's "Sync" is a stellar performer.

FM mode is also included with the DU-250. This is most useful for the 10 Meter Amateur band along with the rare Shortwave pirate that decides to try something out of the ordinary. A squelch control can be found on the rear panel.


24 Hour Clock With Seconds / 2 Event Timer

When the HF-250 is off a 24 hour clock with seconds is displayed (backlight is dimmed). However one can view the clock when powered ON by pressing the FAST and MODE buttons together (NOTE : You MUST be in VFO mode to do this). To return to the frequency display press MODE once and WAIT a second.

2 programmable timers are featured. It does not have relay contacts for a old school tape recorder however.

One Of BEST Sounding HF Receivers Ever Tested (if not the best) / Have Held Up Well With Age

As far as audio quality goes, it's extremely difficult to beat the Lowe HF-250. Mind you it has it's share of "bug-a-boos" as well.

In our view it has held up much better in it's old age vs. the AOR AR7030. Properly operating and in decent condition samples are fairly rare on the used market now (even more so in North America). Most owners know what the receiver is and hang on to them. But once in a great while one does show up on the used market (heed warnings of possible abused parts as covered in the text above !).


Dave N9EWO
© N9EWO, all rights reserved
Ver 2.8

Discontinued Receiver

Lowe HF-250 links for additional Information (all subject to change without notice)

- Lowe HF-250 "Owners Manual"

- Lowe HF-250 "Advanced Information" (Brochure)

- LoweHFReceivers on "groups.io"

HF-250 "You Tube" Video's

- General Lowe HF-250 Video (Japan)

- Lowe HF-250 Filters and Tone Control

- LOWE HF-250 RESCUED AND REPAIRED! (open L46 100 uh choke)

Lowe HF-225 links for additional Information (all subject to change without notice)

(PCD) 5101P RAM IC used on HF-225 Control Board Q204 (available USA source and are very hard find now)

(PCD) 5101P RAM IC used on HF-225 Control Board Q204 (second USA source)


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