WANTED: VIKING 5D

[Qiaozhi]

Just to be sure - if I hold the head parallel to the ground at the same level and no iron is there masking the target (coin) - can I see it for example in 6 inches (as in the air)? I think I have dug one or two pulltabs from that depth - but with the sand I am never sure about the depth. Unfortunately it seems I will not be able to test it today because of the weather.

I am using it for beach only, most of the time the surface is relatively flat with low iron contaminaton where I am.

Even if you keep the search head parallel to the ground, there will be some loss of depth when compared to an air test.

[pelanj]

Just to be sure - if I hold the head parallel to the ground at the same level and no iron is there masking the target (coin) - can I see it for example in 6 inches (as in the air)? I think I have dug one or two pulltabs from that depth - but with the sand I am never sure about the depth. Unfortunately it seems I will not be able to test it today because of the weather.

I am using it for beach only, most of the time the surface is relatively flat with low iron contaminaton where I am.

[Qiaozhi]

I wanted to try that at the end of the day, but I got the problems with threshold. That would really disappoint me - I thought the ground only moves the threshold (that I retune) and sensitivity stays the same.

Although you can retune the threshold, you must keep the search head exactly the same distance above (and parallel to) the ground. Any ferrous objects will move the signal in one direction (causing a null) whereas non-ferrous will shift the signal in the other direction. In theory this sounds good, but in practice the presence of ferrous targets in the soil tend to override the [usually] smaller non-ferrous signals. The result is very poor performance when used in the field. Bearing in mind that the ground itself moves the signal in the same direction as ferrous targets, you can see this is a recipe that is doomed to failure.

[pelanj]

I wanted to try that at the end of the day, but I got the problems with threshold. That would really disappoint me - I thought the ground only moves the threshold (that I retune) and sensitivity stays the same.

[Qiaozhi]

Hello, I have recently bought a Viking 5. I have already been a few times out with it on a beach, but I think I have a problem with temperature. It happened yesterday and today as well, in the evening I just could not set the threshold, it was too loud even at both settings minimal. It started working again after a while at room temperature. Today I remembered to check the temperature and it was 10 °C. During the day it must have been at least something like 16 °C.

Could it be so heavy temperature dependent? I can get with the coarse tuning only a little above 1/4 and never get close to 1/2. Could it be that the tolerances play against each other and R6 from KT315's schematic should be replaced by a smaller one, say 6k8? All my other detectors were able to work down to -5 °C, I would like to get at least to that with the Viking as well.

It is a nice little machine for travelling around and I tend to like its iron rejection, I could hear quite a lot of iron nulls on the beach. The detection range should be sufficient for beach hunting during the season and I can also hunt wet sand with it. What bugs me is the temperature dependence...

The Viking 5 appears to have very good iron rejection when tested in air, but in the ground it's a horror story. Try taking a small coin and see how far you can detect it in air. Then bury the same coin in the ground and see how far it can be detected. The problem with the Viking 5 is its lack of ground rejection. As soon as you place the search head near the ground the threshold level moves, and sensitivity goes out the window. This will also be the reason why you are losing depth on the beach. I used to have one in my collection, but swiftly sold it on eBay.

[pelanj]

Help me with my Viking, please.

Hello, I have recently bought a Viking 5. I have already been a few times out with it on a beach, but I think I have a problem with temperature. It happened yesterday and today as well, in the evening I just could not set the threshold, it was too loud even at both settings minimal. It started working again after a while at room temperature. Today I remembered to check the temperature and it was 10 °C. During the day it must have been at least something like 16 °C.

Could it be so heavy temperature dependent? I can get with the coarse tuning only a little above 1/4 and never get close to 1/2. Could it be that the tolerances play against each other and R6 from KT315's schematic should be replaced by a smaller one, say 6k8? All my other detectors were able to work down to -5 °C, I would like to get at least to that with the Viking as well.

It is a nice little machine for travelling around and I tend to like its iron rejection, I could hear quite a lot of iron nulls on the beach. The detection range should be sufficient for beach hunting during the season and I can also hunt wet sand with it. What bugs me is the temperature dependence...

Actually, there is a White's Coin Getter listed on ebay.com as I have two at home. Still quite cheap

[Qiaozhi]

I got once a White's AF 101 with it's 6" coil: it's not worth its money: no iron rejection at all! I also opened it's coil housing: I only saw a single loop and no caps. FORGET IT!

This is true. The AF-101 is an off-resonance type detector, and therefore has no effective ferrous rejection. It's one step up from a BFO.

AF 101

I got once a White's AF 101 with it's 6" coil: it's not worth its money: no iron rejection at all! I also opened it's coil housing: I only saw a single loop and no caps. FORGET IT!

There is are similar looking White's detectors on the website of White's UK: The Beachcomber 4 (BC 4) and the AF 109.
Both are all metal TR detectors with some built-in iron rejection (cf. Viking 5) and the AF-109 has the same circuit as the BC 4. The BC 4 is built nearly unchanged since 1978 or 1979 (the year I got my first BC 4). The difference between the BC4 and the AF 109 is the searchcoil size: BC 4-8 inches, 2D ; AF 109: 10 inches 2D. Both have inside the coil housing some caps and a variable cap of 80 pF. To get access to the variable cap, you have to drill carefully (!) a hole into the coil housing. The hole has to be drilled on the upper side of the BC4 coil and from the lower side on the AF-109 coil.

Modifying the variable cap setting has some incidence on the iron rejection level. If you try to reject iron too much, the detector becomes too ground sensitive.

In the late 70's, White's also sold an ultra cheap version with a 6" 2D coil called "Beachcomber-TR" and "Coin Getter". A fantastic little machine! Basically, it has the same circuit as the BC 4. Nowadays, it can be found for around 10-30 $. It is comparable to the Compass Coinhustler. The latest version of the Compass Coinhustler (around 1983) was available with an S-shaped stem and an 8" coil.

Back to the White's BC 4: it also works with a 4B coil of the earlier Beachcomber 6 or Coinmaster and Alaskan models, but it works best with the 2D coil.

AF 101

I got once a White's AF 101 with it's 6" coil: it's not worth its money: no iron rejection at all! I also opened it's coil housing: I only saw a single loop and no caps. FORGET IT!

There is are similar looking White's detectors on the website of White's UK: The Beachcomber 4 (BC 4) and the AF 109.
Both are all metal TR detectors with some built-in iron rejection (cf. Viking 5) and the AF-109 has the same circuit as the BC 4. The BC 4 is built nearly unchanged since 1978 or 1979 (the year I got my first BC 4). The difference between the BC4 and the AF 109 is the searchcoil size: BC 4-8 inches, 2D ; AF 109: 10 inches 2D. Both have inside the coil housing some caps and a variable cap of 80 pF. To get access to the variable cap, you have to drill carefully (!) a hole into the coil housing. The hole has to be drilled on the upper side of the BC4 coil and from the lower side on the AF-109 coil.

Modifying the variable cap setting has some incidence on the iron rejection level. If you try to reject iron too much, the detector becomes too ground sensitive.

In the late 70's, White's Beachcomber also sold an ultra cheap version with a 6" 2D coil called "Beachcomber-TR" and "Coin Getter". A fantastic little machine! Basically, it has the same circuit as the BC 4. Nowadays, it can be found for around 10-30 $. It is comparable to the Compass Coinhustler. The latest version of the Compass Coinhustler (around 1983) was available with an S-shaped stem and an 8" coil.

Back to the White's BC 4: it also works with a 4B coil of the earlier Beachcomber 6 or Coinmaster and Alaskan models, but it works best with the 2D coil.

[kt315]

.

[Qiaozhi]

Thanks KT315. At least someone is awake.

The COARSE and FINE controls were swapped over, and one resistor value was wrong. Updated schematic below.

By the way, in your version of the schematic, the audio transistor should be a ZTX712 (darlington), not ZTX512. Also, the search head contains 3 coils with a shared connection that is wired to the screen. The 3 coils are the TX, feedback, and RX. As I said before, the TX circuit is like a cut-down version of a Heathkit GD-48.

If you spot any other mistakes, please let me know.

[kt315]

check the schematic

[Eugene52]

WANTED OR NOT WANTED: VIKING5 ???

Hi Eugene ,go to scanned copy on the top in Sprint on the right,than load bidmap, must be a BPM file scan or pic,than you can trace it over.I hope you can understand me.Grt Nakky.

Thanks Nakky , the .bmp files are the biggest size of any image format , meaning they are like a High-Definition file so sprint can convert it to a .lay image with more precision . But this Viking5 here seems like a T/R -I.B. Combo and seems they copied from Whites beachcomber AF-101 ???? It is fine that someone wants to work and study the Viking5 here . But is the Whites here a better Detector even though it does not discriminate ?? Please , opinions are very welcome here , and I do not mean to change the subject !!! The good and amazing news is taking a .BMP image and converting it to a sprint .lay file !!!..........Take Care all..............Eugene52

[nakky]

Patrick , Awesome work !!!! I did not know of any Sprint version that could convert from an image to a PCB layout ....What version ???....Please let us know more !!! There are some images on this forum , especially the New up-dated Hammerhead that would be great to have in "Sprint" .LAY FORMAT !!! To me this is Great News , 2009 is starting out very Good , Thank-you again Patrick , and everyone for this new posting of information !!!!!!!..............Regards..........Eugene52

Hi Eugene ,go to scanned copy on the top in Sprint on the right,than load bidmap, must be a BPM file scan or pic,than you can trace it over.I hope you can understand me.Grt Nakky.