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Conar 500 Receiver - Anyone Have the Assembly Manual?

Discussion in '"Boat Anchor" & Classic Equipment' started by KE4OH, May 14, 2018.

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  1. KE4OH

    KE4OH Ham Member QRZ Page

    Well, I just had to have one of these, and now I do.

    But, I can't seem to find a copy of the assembly instructions anywhere on the internets. I don't really need them, but I'd sure like to have them just to make the package complete. Can anyone help?

    I found a copy of the Service Manual, which includes the schematic, parts list, voltage/resistance charts, and alignment instructions. But no dice on the assembly instructions.

    Mine was DOA, but I got it working pretty well on 40m with a little bit of soldering and lead bending. Shouldn't be too hard to get 80m and 15m working. Mine looks like it was generally built okay. Soldering was pretty good overall, but there are (were) a ton of fly leads sticking out everywhere. I did find one missed solder joint and that got it working.

    It also looks like someone came along later and reworked it somewhat. The tubular caps are certainly replacements, which is fine by me. But it also looks like maybe the 3 IF cans aren't original. The mounting studs don't match the cutouts in the chassis and they also look like maybe they are cap tuned. They each have two slot head adjustment screws on top. The alignment instructions refer to upper and lower slug adjustments on the IF cans, which would further indicate that these aren't original. Why the heck someone would bother "upgrading" the cans is beyond me!

    Having said that, even before aligning the thing, I'd have to say that it isn't bad at all. Much better than all the trash talk I've read about them. It sure beats the living daylights out of receivers like the Hallicrafters S-38 series (though it is not general coverage). It has a real BFO on a fixed frequency that injects plenty of signal. Broad as a barn, but I'd have to say that it's at least as selective as a Heathkit HR-10. I have a self-powered WRL Q-multiplier that I think will be a good addition to this beast. Biggest surprise is that there is no vernier dial drive.

    Anyway, an interesting unit that I can't wait to use on the air! Gotta get a fuse and 3-wire plug on it plus get rid of the selenium rectifier before it fumigates my house...

    73 de Steve KE4OH
    Last edited: May 14, 2018
  2. W7UUU

    W7UUU QRZ Lifetime Member #133 Volunteer Moderator Life Member Platinum Subscriber QRZ Page

    The Conar 500 is ~passable~ for sure. Utterly broad as the proverbial barn - really needs an AF filter on the output.

    It's the Conar 400 transmitter that's an utter failure. I have never got one to work "right". I actually have a nice Conar Twins pair that one of these days I plan to get on the air, but not without a significant re-do of the transmitter side of things.

    Regarding the manual, they do come up on eBay fairly often.

    KE4OH likes this.
  3. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    KE4OH likes this.
  4. N8AFT

    N8AFT Subscriber QRZ Page

    I have two of them critters, one works FB on 40 the other FB on 80. Crystal selection is tricky to get a clean note I have found.
    Can't recall if I added an 0a2 to the screen grid on one of them or not. Anyways, I used them both throughout last winter with no trouble.
    Don't have and never wanted the receiver.

    Learn Morse.
    Do CW.
  5. KE4OH

    KE4OH Ham Member QRZ Page

    I had a couple of (mis)construction issues that were confusing me that the schematic didn't address. I thought the construction booklet would help me there. But no matter. I figured it out well enough to get this thing working very decently. The link Glen provided was helpful, but I wasn't willing to spend nearly as much for the manual as I spent on buying the rig.

    Mine for sure had different IF cans installed than the originals. Who knows why they were changed out? These seem pretty good, though. I got them tuned pretty sharp at 455Kc. I got rid of a lot of excessive lead lengths in the tuned circuits and repaired a busted oscillator coil. I also found that I was wrong that it has no vernier dial. It does! Mine was just frozen in place by solidified grease.

    I spend a lot of quality time with my signal generator and volt meter. Now this thing is pretty dang usable. I can't figure out why, but 40m is a lot hotter than 80m, though 80m is good enough.

    The biggest surprise is that it hears pretty well on 15m even though there is no RF amp stage in this radio. The band has been open some the past few days, and the 500 can pick up some of it. Certainly much less deaf than my Heathkit HR-10B, the undisputed champ of 15m deafness.
  6. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page


    Obviously, you have never used one of the Hallicrafters S-38- series, or, even worse, the National SW-54 on 15-meters! If then, you would consider the Heath HR-10 / HR-10B to be very sensitive!

    It is the Conar 400 transmitter that is a real problem. Those transmitters chirp, to high Heaven, even when disconnected from the AC mains, put in a box, and then that box be put in the far corner of the attic! Yes, I do have a Conar 400 transmitter and would like to have the matching Conar 500 receiver!


    Glen, K9STH
  7. N2EY

    N2EY Premium Subscriber QRZ Page

    Last edited: May 18, 2018
  8. N2EY

    N2EY Premium Subscriber QRZ Page

    More gain and improved selectivity. All 455 kc IFTs are NOT the same!

    There may be some regeneration going on....

    See below about the HR-10 design.

    The HR-10 tends to be "deaf" above 20 meters for at least two reasons:

    1) On 10 and 15 meters, the HR-10 operates the local oscillator at half the frequency needed for mixing, and depends on the second harmonic product to produce the required heterodyne action. How well this works is.....debatable at best. At the very least, it means a big loss in mixer gain. (This was done in the hope of greater LO stability).

    2) The front-end tuned circuits of the HR-10 are very high C on the higher bands - particularly 15 and 10. This means they are very low L, which makes them relatively low impedance at resonance. The end result is low gain in the RF stage.

    In the HR-10, the tuning capacitor is directly across the tuned circuit on all bands, and there is only one section for each function. This means the same amount of capacitance variation (delta C) must tune the circuit from 3.5 to 4 and from 21.0 to 21.45. But - the higher bands are much narrower as a percentage of the center frequency, and they need less overall LC to resonate.

    What is usually done in hollow-state receiver designs to deal with the widely varying LC requirements of different bands is to either:

    - use a variable capacitor with multiple sections for each stage, and switch sections out on the higher bands (this is done in the HW-101 and similar)
    - switch in series capacitors to reduce the delta C on various bands
    - tap the variable capacitor down on the coil to reduce its effect

    But the HR-10 does none of those, because they all require a more-complex bandswitch and/or tuning capacitor, coils, etc.

    If someone were really dedicated, they could redesign the bandswitch and coils to allow the use of higher L in the front end. But it would be a monumental project, particularly if it were desired to match the original dial scale. Using a converter in front of the receiver would be much easier.

    Such a converter could be built in an external box to match the HR-10, with matching paint and knobs. Depending on the design, it might be powered by the HR-10 via the accessory socket.


    While the Conar 500 is, there were MUCH better choices for the Novice of that era.

    For example, a BC-453 with crystal controlled converter for 80 and 40 would run rings around the Conar 500, and in the days of abundant cheap surplus, could be built for less.

    73 de Jim, N2EY
  9. KE4OH

    KE4OH Ham Member QRZ Page

    Thanks Jim! But I do have that manual, which includes the schematic and alignment instructions (totally conventional alignment process, though.) I was hoping to find a construction manual. Mainly just to have it. But there were a couple of mysteries (to me) in my set which the construction manual might have sorted for me. But I figured them out anyway. Just stuff like the IF cans, Whether one or both sections of the tuning cap should be in circuit (just one!), the vernier dial mechanism, and a few wiring mysteries. Hammy Hambone had been at work on mine before I got it. It seems like every rig I buy has been through his workshop...
  10. KE4OH

    KE4OH Ham Member QRZ Page

    Ha! Well, I actually have had the "pleasure" of an S-38! I was just comparing this Conar to another low-end ham band-only rig that I'm familiar with. In general, the HR-10 is better in a lot of ways. But it's just not good at all on 15m and 10m, for the well-known reasons that Jim and others have stated over the years. I simply was surprised and pleased that such a simple beast, the Conar, would do anything worthwhile at all on 15m.

    73 de Steve KE4OH
    N2EY likes this.

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