Lowe HF225 Europa: is that a factory modification? - UK Vintage Radio Repair and Restoration Discussion Forum

netsmo62 · 23rd Jan 2021, 6:06 pm

Goodmorning, a customer sent me an HF225 Europa that needed a repair to the impedance transformer of the antenna input at 600 ohm but then doing a comparison test with my standard HF225 I noticed with disappointment that Europa was much less sensitive than my receiver, we are also talking about 2-3 "S" points less in every bands and I don't think it's my radio with out-of-the-ordinary performance. Inspecting the main board I noticed what looks like a handcrafted modification that you can see in the attached pics,
that is the insertion of a 3 Khz MuRata K455J ceramic filter and an added shielded coil on the right on the pic compared to the standard HF 225. Is this a modification that was made from the Lowe factory or a "home made" one? I have also tried to re-made many soldering from antenna input to first mixer SL6440 but nothing change...if this can help you, in 2002 this receiver was shipped back to Lowe for a repair due a BA244 PIN diode failure which had silenced the receiver below 14 Mhz.

I thank in advance anyone who can help me, I haven't found any internal photos of this radio model on the net.

Hi, F.

Radio Wrangler · 23rd Jan 2021, 6:45 pm

It is fairly neatly done as such bodges go. However, having one of those 1000u inductors over the top of a resistor and nothing to support it is not nice. The inductors will be for biasing the diode switches in the signal path. They may be replacements for physically smaller parts in an attempt to reduce non-linearities from them.

There is the possibility that the MuRata filter has higher insertion loss than whatever you have in yours, there is also the possibility that it's badly mis-matched.

Is the sensitivity bad in all modes?

It's worth taking a photo of this area of your receiver. for comparison.

David

netsmo62 · 23rd Jan 2021, 7:08 pm

Quote:

Originally Posted by Radio Wrangler

It is fairly neatly done as such bodges go. However, having one of those 1000u inductors over the top of a resistor and nothing to support it is not nice. The inductors will be for biasing the diode switches in the signal path. They may be replacements for physically smaller parts in an attempt to reduce non-linearities from them.

There is the possibility that the MuRata filter has higher insertion loss than whatever you have in yours, there is also the possibility that it's badly mis-matched.

Is the sensitivity bad in all modes?

It's worth taking a photo of this area of your receiver. for comparison.

David

Shielded inductors replaced simple inductors from Lowe to increase skirt selectivity in the PB section, however in my standard HF225 (see pic) that inductor over D20, R31 and R33 there's not and otherwise over board soldered resistors is not a "Manhattan" mod, it have its pads on the board. For this reason I think it's an impromptu modification of Lowe also because the "Europa" model was built in a very limited edition.

I hope some Europa owner can read this post and solve this puzzle...thanks for reply.

Hi, F.

John KC0G · 24th Jan 2021, 6:25 pm

I think that this was a factory modification. Please join the LoweHFReceivers group at groups.io https://groups.io/g/LoweHFReceivers where you will find internal pictures of the Lowe HF-225E. I am the group owner and assembled the group when the two previous groups at Yahoo were closing down. There are files, photos and all of the original messages related to radio (I removed 16,000 porn messages). They are not in the original form, but they are word searchable in a browser. There is a lot of knowledge there, and some of it directly from a former Lowe employee.

There were two main changes between the HF-225 and HF-225E.:
1. The filter line-up was changed to 2.2kHz, 3.3 kHz, 4.5kHz and 7kHz. I think that they also changed other filters. Any way the filter matrix was changed, and so the firmware was changed.
2. Various components were changed to decrease filter leakage. Here is some of the information which I have found. Toko 10RB series screened 1mH chokes were fitted in IF filter stage. SMD decoupling capacitors were fitted in IF filter stage. Low capacitance switching diodes were used in IF filter stage (not sure about BPF but likely the same)
In addition there were some small changes made round the first and second mixers, but I do not know the details.

The information in the group archived messages indicates there was no specific service manual for the HF-225E. The HF-225 service manual will "get you most of the way".

Going back to your original question, in the photos section I see the same PCB number on those for the HF-225 and HF-225E. Given that the filters were different, I think you are looking at a factory modification.

HTH and 73

John KC0G

netsmo62 · 25th Jan 2021, 9:53 pm

Thanks for the reply, I will definitely join the Lowe receiver group. This "Europa" is not mine, but I still have a HF225 with AMS which is really good and is currently my main receiver.

Yes, I also think that this is a modification made in the factory on the basis of a standard HF225, even if as you can see from the photos in addition to the MuRata K455J filter, an inductor has been added near the diode D20 and the resistors R31 and R33 and not it is a flying modification but they have made a modification to the tracks, while the rest as you can see is mounted "manhattan style".

I asked for information from a Swiss SWL who had dealt with "Europe" and he sent me a technical note in which he spoke of a 3.3 Khz filter placed on the line of the 10 Khz IF filter and so it is. There remains the problem of reduced sensitivity (I don't want to talk about a deaf receiver) which causes the receiver to lose at least 2-2.5 "S" points in each band at least whichever IF filter is used, compared to my HF225. I have tested all the PIN diodes (BA244) and they are all fine, I have redone the soldering around the whole area between the antenna input and the first SL6440 mixer, but nothing changes.

For the rest, the radio works perfectly. To tell the truth I had convinced the owner to sell it to me at a reasonable price (given the problem, moreover recognized by him) but then his wife got in the way who resented because this radio had been bought in the UK by a friend of family and you know how these things go if wives get in the way! No problem, it will be for the next "Europe" and then the guy doesn't necessarily think about it in the future...

OK, I'm signing up for the Lowe group! Thanks again! F.

23rd Jan 2021, 6:06 pm	#1
netsmo62 Tetrode Join Date: Nov 2020 Location: Nonantola (MO), Italy Posts: 56	Lowe HF225 Europa: is that a factory modification? Goodmorning, a customer sent me an HF225 Europa that needed a repair to the impedance transformer of the antenna input at 600 ohm but then doing a comparison test with my standard HF225 I noticed with disappointment that Europa was much less sensitive than my receiver, we are also talking about 2-3 "S" points less in every bands and I don't think it's my radio with out-of-the-ordinary performance. Inspecting the main board I noticed what looks like a handcrafted modification that you can see in the attached pics, that is the insertion of a 3 Khz MuRata K455J ceramic filter and an added shielded coil on the right on the pic compared to the standard HF 225. Is this a modification that was made from the Lowe factory or a "home made" one? I have also tried to re-made many soldering from antenna input to first mixer SL6440 but nothing change...if this can help you, in 2002 this receiver was shipped back to Lowe for a repair due a BA244 PIN diode failure which had silenced the receiver below 14 Mhz. I thank in advance anyone who can help me, I haven't found any internal photos of this radio model on the net. Hi, F. Attached Thumbnails

23rd Jan 2021, 6:45 pm	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,870	Re: Lowe HF225 Europa: is that a factory modification? It is fairly neatly done as such bodges go. However, having one of those 1000u inductors over the top of a resistor and nothing to support it is not nice. The inductors will be for biasing the diode switches in the signal path. They may be replacements for physically smaller parts in an attempt to reduce non-linearities from them. There is the possibility that the MuRata filter has higher insertion loss than whatever you have in yours, there is also the possibility that it's badly mis-matched. Is the sensitivity bad in all modes? It's worth taking a photo of this area of your receiver. for comparison. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

24th Jan 2021, 6:25 pm	#4
John KC0G Hexode Join Date: Mar 2009 Location: Minneapolis, Minnesota, USA. Posts: 278	Re: Lowe HF225 Europa: is that a factory modification? I think that this was a factory modification. Please join the LoweHFReceivers group at groups.io https://groups.io/g/LoweHFReceivers where you will find internal pictures of the Lowe HF-225E. I am the group owner and assembled the group when the two previous groups at Yahoo were closing down. There are files, photos and all of the original messages related to radio (I removed 16,000 porn messages). They are not in the original form, but they are word searchable in a browser. There is a lot of knowledge there, and some of it directly from a former Lowe employee. There were two main changes between the HF-225 and HF-225E.: 1. The filter line-up was changed to 2.2kHz, 3.3 kHz, 4.5kHz and 7kHz. I think that they also changed other filters. Any way the filter matrix was changed, and so the firmware was changed. 2. Various components were changed to decrease filter leakage. Here is some of the information which I have found. Toko 10RB series screened 1mH chokes were fitted in IF filter stage. SMD decoupling capacitors were fitted in IF filter stage. Low capacitance switching diodes were used in IF filter stage (not sure about BPF but likely the same) In addition there were some small changes made round the first and second mixers, but I do not know the details. The information in the group archived messages indicates there was no specific service manual for the HF-225E. The HF-225 service manual will "get you most of the way". Going back to your original question, in the photos section I see the same PCB number on those for the HF-225 and HF-225E. Given that the filters were different, I think you are looking at a factory modification. HTH and 73 John KC0G

25th Jan 2021, 9:53 pm	#5
netsmo62 Tetrode Join Date: Nov 2020 Location: Nonantola (MO), Italy Posts: 56	Re: Lowe HF225 Europa: is that a factory modification? Thanks for the reply, I will definitely join the Lowe receiver group. This "Europa" is not mine, but I still have a HF225 with AMS which is really good and is currently my main receiver. Yes, I also think that this is a modification made in the factory on the basis of a standard HF225, even if as you can see from the photos in addition to the MuRata K455J filter, an inductor has been added near the diode D20 and the resistors R31 and R33 and not it is a flying modification but they have made a modification to the tracks, while the rest as you can see is mounted "manhattan style". I asked for information from a Swiss SWL who had dealt with "Europe" and he sent me a technical note in which he spoke of a 3.3 Khz filter placed on the line of the 10 Khz IF filter and so it is. There remains the problem of reduced sensitivity (I don't want to talk about a deaf receiver) which causes the receiver to lose at least 2-2.5 "S" points in each band at least whichever IF filter is used, compared to my HF225. I have tested all the PIN diodes (BA244) and they are all fine, I have redone the soldering around the whole area between the antenna input and the first SL6440 mixer, but nothing changes. For the rest, the radio works perfectly. To tell the truth I had convinced the owner to sell it to me at a reasonable price (given the problem, moreover recognized by him) but then his wife got in the way who resented because this radio had been bought in the UK by a friend of family and you know how these things go if wives get in the way! No problem, it will be for the next "Europe" and then the guy doesn't necessarily think about it in the future... OK, I'm signing up for the Lowe group! Thanks again! F.