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Author Topic: Classic boat anchors --modify to improve performance or leave it alone.  (Read 11523 times)

Posts: 5

« on: October 31, 2013, 06:11:10 PM »

I have a Heathkit HR10 and its performance is typical of all of them with stability and lousy avc control.
There are all kinds of modifications to improve the performance of this receiver but my question is this to the collectors of boat anchors. Some time in the future I could be selling this thing. If I were to modify it, would that
be a negative factor in your buying decision? Would you rather have a original or a modified one?
The modifications would be a regulated power source for the BFO, a new AVC circuit design using solid state components.
I have already isolated the detector leaving it in place by replacing V5, the triple diode with silicone diodes.
I stopped there waiting for a collectors recommendation of what can or should not be done. I have many other
rigs to use so I am not isolated to just one receiver.
Thanks for your input.
Robert KH2BR

Posts: 59

« Reply #1 on: October 31, 2013, 06:46:33 PM »

Hi Robert,

I don't know that the HR-10 would fall into the "classic" category of boat anchors, but I would vote for leaving it original. Sometimes it is kind of interesting to see what the state of the hobby was at various times in the past. When I listen with my old Heathkit AR-3 or Hallicrafters S-20R, I am amazed that I stayed with the hobby and actually made contacts. But, when you are 13 and trying to support your hobby with a paper route, you learn to work with what you are able to manage. Using an old radio (as it was designed) gives you a real sense of appreciation of both how capable some of the older equipment was as well as how much the state of the art has advanced.

Bob AB1MN (ex K7DYB)


Posts: 4710

« Reply #2 on: November 01, 2013, 08:57:46 AM »

Seems to me the best approach is to modify it but make the mods reversible. And document them thoroughly. That way, a future owner can undo any changes.

For example, the voltage regulator could be built on a terminal strip or bracket in such a way that it does not put any new holes in the chassis, nor mess up any wires in the harness (if there is one). Same for AVC mod.

Of course the sad fact is that an HR-10 is a bit of a sow's ear and no matter what you do it will have "issues".

73 de Jim, N2EY


Posts: 5030

« Reply #3 on: November 01, 2013, 01:08:58 PM »

The only mods I ever do are service bulletins or corrections to "KNOWN" flaws. I am very hesitant on performance improving mods, especially if they are in the transmit circuit. I am more forgiving in received mods, and even more in receive audio mods.

Posts: 2085

« Reply #4 on: November 01, 2013, 02:15:24 PM »

my old novice HR-10 was marginally better than a tub of dirty water on the air.  so I juiced it with the frame-grid mixer and RF amp mods.  ehhh.  adding a mosfet noise blanker was a better investment, even got an Amidon kit and etched a PCB for that. also added a VR tube on the tuneable oscillator, which was a decent deal.

since that radio was so iffy, who cares.  it worked OK on 80 and 40 afterwards.

these days, I just bring my projects up to snuff and see what they do.  something really creepy that has well-documented fixes that FIX, like the power supply in my bench queen CX7, we do the eventually factory-implemented mods and then tune for minimum smoke.

Posts: 72

« Reply #5 on: November 01, 2013, 02:47:53 PM »

If you choose to modify the thing be sure to keep documentation with the radio so future owners can see what you have done.  I have a friend with a highly modified Valiant who is almost to the point of parting it out because of EXTENSIVE audio modifications and he does not have the diagrams or description.

To make matters worse the person who modified it is SK so no help there.  Modifications that improve stability are fine but tape the diagram in the cabinet because, in estates, paperwork never follow the set.

Posts: 62

« Reply #6 on: November 01, 2013, 04:26:35 PM »

I have no modern radios in my shack as of last month, almost all of them have tubes in them, while the two that are solid state are old enough to be called classic.

Here is what I am thinking;

out of all of them, which include some high end stuff (SP-600, RCA AR88 to name a couple), I have modified many of them to improve their performance.

See unless you have museum quality or a unique piece of equipment - like new in the original box - modifying the radio internally won't harm it nor will it make it less of a radio for doing it. I came to this conclusion while trying to use a couple of them and knowing that without the modification makes it more difficult to use in the long run.

Posts: 379

« Reply #7 on: November 01, 2013, 05:21:51 PM »

I agree with minimum impact and documentation.  What "mods" scare people is crudely added switches, pots and connections with badly placed and hacked holes in the case, etc. Or inside mods that look like crude or poor workmanship.  I have a classic Yaesu that has some additional wires inside that are not terminated anywhere and look like some sort of half arsed mod that was hastily removed.  Have not even figured out where the wires go, as it is a someday refurb. But the radio works basically, so it must not have been too drastic. Some mods are as old as the radios, and very beneficial, some were later incorporated into production, and some mfrs put out notices and letters making them official mods.

Posts: 5

« Reply #8 on: November 01, 2013, 06:08:36 PM »

Thanks for all of the advice. I see that the consensus is to proceed with the mods in a professional manner with out molesting the unit and follow up with documenting what had been done. This receiver is not museum quality
but any improvement in its operation will make operating it more enjoyable then what it is now. If it was pristine,
then I agree with hands off the innards.
Thanks to all of you and 73's
Robert KH2BR

Posts: 578

« Reply #9 on: November 03, 2013, 10:25:39 AM »

Robert your Heathkit receiver is a dog of sort, so mods are not going to help it. Look for one of the winners and then love it, I like the Drake receivers I have 2B and an R4C and don't know of much that will out play them, plus they don't need a bunch of so called Mods..some Hams go goofy on installing their mods, look at all the crap that goes on with SB200/SB220 and Drake L4's, most have worked for 30 plus years without a worry...but now O Joe says it needs a mod or two...Denny K8KAS

Posts: 2568

« Reply #10 on: November 03, 2013, 12:07:21 PM »

It is a philosophical question. Collectors who are purists will not like you changing a single thing. They would insist upon you keeping components in the radio like BBOD's (black beauties of death capacitors) or even paper capacitors of the same generation as when the radio came off of the manufacturing line.

Somewhere in the middle are people who will re-stuff old caps with the internals of a modern capacitor and try to keep the radio looking like it is still original but functioning with more modern components.

Another middle ground would be to stick with the same intent as the original manufacturer but with modern components like Orange Drop capacitors, teflon wiring, ceramic tube sockets, ceramic disk, poly or tantalum instead of mica caps and new resistors (not necessarily carbon comp).

There are the modders who will make minor circuit changes to fix things like bad AGC action, improved selectivity, better audio response, etc... but still stick with the same basics. There may be minor wiring changes and component value selection.

The far end will have radios that have been solid-stated, major sections of the radios gutted and started over, synthesizers installed where a permeability tuned oscillator was in place.

Often you are going from classic components and build up to radios that bear only a casual similarity of what was originally put in place. Another factor that will really get folks wound up are hare-brained mods that have not been documented and may not work that were not documented or things that completely change the character of what the radio used to be.

Personally I am happy with upgrades to modern components but still using tubes. Well proven and group accepted component value changes and maybe a few changes to use tubes of a more advanced model. Some changes in capacitor/resistor values to fix clearly deficient designs (where the original engineer had a brain-fart or just did not have time to make a particular circuit design perfect). If I have a problem with bad, cloth-covered wire I will rewire the entire radio, for places where heat was a concern I will increase the wattage of the resistors and go with flame-proof components. Make minor changes to capacitor values in the audio deck to replace paper or oil caps with poly, teflon of tantalum. Everything well documented and peer reviewed by the folks who have been doing it for a very long time (R-390 reflector).

It may take three to four months to go through a radio from top to bottom, review each change with a group of experts, complete perfect component replacement techniques (my work always looks much better than factory).

Even with this moderate approach there are purists who will cry "heretic!" and want to roast me over a fire of out of spec resistors.

Chopping holes, adding buttons, dials, switches or hacked in mods are a no-no.

Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
Free space loss (dB) = 32.4 + 20 × log10d + 20 × log10 f

Posts: 2483

« Reply #11 on: November 04, 2013, 05:54:23 AM »

If the radio is truly a classic I vote to leave it as-is.  The only true classics I can think of are most all Collins and perhaps some of the rarer Drakes, a few of the Hammarlunds, maybe one of the rarer Nationals, and possibly a few others.  The reason I picked these as classic rigs, is their resale prices seem to keep going up and up.

As far as the rest of them I say if their performance can be enhanced, go for it.

Dick  AD4U

Posts: 290


« Reply #12 on: November 12, 2013, 03:11:25 PM »

I put most of the Sherwood mods into my Drake 4C receiver and it made it perform better than new. I think another valid case is installing roofing filters in Yaesu FT-1000s and MPs, and other W8JI mods (key click, noise blanker mods) that enhance performance.

The factory does not always get it right!

Mike, W7VO
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