Entries from September 2012 ↓

Tips on Buying used Equipment

This post is to remind me on ways to avoid dissappointment.

There are a limited number of ways to buy used equipment, at an auction (a real auction, not ebay), off a classified listing on-line, from a dealer, from a ham you know, ebay, hamfest and newspaper classifieds.

The best way to do the deal is a one on one with the seller in an environment where he can demonstrate the equipment and you can personally carry it home after the demonstration. Show me that it works and I will show you the money. Pay cash. No reason to give out your bank account information and the seller does not have to worry about a bounced or stopped check. No tax and no shipping. Just an exchange of items of value.

Some would say the suggestion above shows a high degree of paranoia. I have been selling and buying equipment since 1959. Fortunately the good deals have outnumbered the bad and the bad deals have all occurred long ago in past ancient history. That was after I realized that being prudent and careful is not being paranoid.

In an auction do not overbid. All bidders loose in a bidding war and the winner also looses money. See if you can bid on condition that the item works. Pay by credit card if at all possible. That way you can contest the charge if things go wrong.

Even before you go shopping, get an idea of how much you are going to spend. Just because the fellow with the rig tells you he wants $1000 for an untested, 30 year old amplifier, make sure you know it is worth that much AND that it works. Maybe have him put a sold sign on it and meet after the event somewhere where he can prove that it works before you show him any money.

This is not a matter of trust. It is more a matter of trust but verify. You are not verifying if you can trust the guy, You are verifying that the equipment works as it should and has no major problems. Not everyone is a technical wizard. Today, if you can read, you can get an Extra class license. He may not know his equipment is not working correctly. You don’t want to be in your shack, lifting the lid on the thing to find where the smoke is coming from.

If you notice the seller showing any reluctance to demonstrate the equipment, and you still want the equipment, offer him salvage value. A $1000 amp has a salvage value of $300 and then only if you have or can get the parts and expertise to repair it.

One of the more important exercises is to determine value before you buy. Recently I found a listing for a Drake L4B for $850 plus shipping. The universal Radio used list showed a Drake L4B with power supply had sold six months ago for $549. With shipping that mail order amp would have cost close to $1000, twice what its worth. There was another listing for a L4B that wanted $1100.

Trying to get information on items listed on-line via e-mail is sometimes like pulling teeth. Wishy washy replies, tardy replies, inconclusive or questionable information are all reasons to take your business elsewhere. My response rule allows 24 hours for a reply. I usually ignore any replies after the first 24 hours. I figure if it takes someone longer to come up with an answer, it is probably not one I would believe. It also needs to be a responsive response. If I asked a question in my e-mail, I expect an answer to that question in the e-mail reply. Missing answers get ignored. I have had instances where miscommunications via email were blamed on poor email services. The problem is always the fault of some outside entity beyond their control. This is a way of avoiding responsibility. Makes you wonder who they will blame if they forget to ship the item you bought.

Be particularly cautious about descriptions that don’t do any describing. ‘It worked the last time I used it’, ‘It is as clean inside as outside’, ‘full power output’, ‘mint condition’, ‘excellent’. Notice that all of these expressions are conclusions the seller would like the buyer to come to. A buyers conclusions need to come from the analysis of facts, not wishful thinking on the part of the seller.

Sometimes a seller will claim the equipment cannot be tested because he does not have an antenna, dummy load, power supply or other needed equipment. Well if he can’t test it, you may not be able to use it either. In essence you are being told that he does not want to earn the sale, he just wants your money. Time to look elsewhere.

Tech specials. If you are good at fixing stuff, this could be a good deal but first find out why the seller thinks it is special. ‘It is an easy fix’ is not a valid diagnosis. If it realy was an easy fix it would not still be broken.

I tend to avoid doing business with people working out of P.O. Boxes. These folk are either homeless or have something to hide. Maybe they don’t want you to know where they live. I wonder why but have no desire to find out so I avoid them.

I have heard some good things and some bad things about paypal. I have also had some less than positive experiences with paypal. Trouble in closing an account. The account had ten cents left in it and they wanted to charge me a fee for closing it. So I closed the bank account associated with paypal and quit using paypal.

Now when I need financial services, I go to my bank. My bank provides adult professional services and does not make up rules to suit their whimsey. The bank does not pretend to be ‘your pal’ and works with all parties involved in financial transactions. Paypal offers buyer protection only for ebay transactions. They also tend to change rules without user consent or approval. This results in the user being involved in an open ended contract over which he has no control. The end result is that you surrender your financial rights and control of your bank account to an on-line auction house who claims to want to be your pal. This does not make sense to me so I don’t use paypal. I tend to avoid service providers who are only interested in serving themselves often at their clients expense.

Free shipping. If you believe there is such a thing, you probably also believe in the tooth fairy. When offered free shipping, see if the fellow has any free radios too. That way you don’t have to send him any money at all, just your address.

Shipping is a burden. It is not tax deductable and does not add to the value of the equipment. In fact, shipping risks trashing the equipment being shipped. Shipping does save the buyer having to drive to the seller to make the purchase. When and if such a trip can be justified, a personal one on one transaction is always preferred. For items valued over $100 or where shipping costs are as much as purchase price, a one on one transaction must seriously be considered.

Original owners of equipment normally have the original manual and shippers associated with the equipment. Those sellers offering ‘a copy’ of the manual are probably in possession of orphaned equipment. There may be nothing wrong with the orphaned equipment but the chances that it has problems become greater as its distance from the original owner increases.

‘I am selling this for a friend’ It is safer to ignore these sellers. The same goes for estate and sk sales and any other situation where you may be dealing with a third party that may not own the equipment being sold. Buying stuff from a person who does not own what he is selling is illegal in most states. Your new purchase could be confiscated and you might end up doing jail time along with the clown who sold you the stolen merchandise.

Catchy, non-descriptive phrases, should raise suspicion especially if they sound wordy or high folutin. For instance. ‘this equipment is excess to my needs.’ The phrase endeavors to imply that the person is just swimming in an overabundance of desirable equipment and is going out of his way to share his plenty with the less fortunate.

It could also mean that he is trying to sell a trashed radio. Most people don’t need trashed radios. Thus such items are also ‘excess to a buyers needs’. See if you can find out an honest answer to what made the equipment ‘excess to needs’. Ask for more information and try to determine if the equipment may be excess to your needs as well.

Inquiries that do not result in good answers providing useful information are reasons to look elsewhere for a purchase. Recently I saw an ad selling used coax. I asked if the coax shield was copper and I got an ‘I don’t know’ for a reply. That made me wonder what else he was unwilling to tell me.

Avoid any and all references to mint condition. The term ‘mint’ comes from the action of minting coins. A ‘mint’ condition refers to the condition of a coin that has just been struck and is untouched by human hands. When used to describe radio equipment the term ‘mint’ refers to that new smell that comes from the opening of a factory sealed shipper. The terms ‘mint’ and ‘used’ are mutually exclusive. That is to say ‘used’ can be ‘as new’ but it will never be ‘mint’. Those claiming their used equipment is mint are either lying or mistaken. Makes you wonder what else they are lying or mistaken about.

Pictures are important even if they are not of the actual equipment being offered. Of course the pictures need to be of a comperable (exact) model. Pictures make it easier for a buyer to understand what is being offered. The less effort a buyer needs to expend to come to a buying decision, the more likely he is to make a purchase. ‘Pictures on request’ or ‘go to this website’ are turn-offs. The more conditions you put on the buyer, the less likely he is not to buy your stuff.

Poorly worded ads, ads that use bad grammar or lots of slang give prospective buyers insight into the character, education, and demeanor of the seller. A negative insight does not help in making a sale. Is his unprofessional posting his only sin or does that unprofessionalism extend to other activities as well? Would you risk sending money to a person who has demonstrated a lack of attention to detail? Maybe those misspellings are purposeful so that he can later claim he never offered what you thought he meant. Sort of makes your skin crawl, doesn’t it?

‘ 4 sail ‘ That is not funny. It is just stupid. Most buyers would prefer not to deal with stupid people.

‘Shack Cleanup Sale’ Do you really expect someone to give you money for your floor sweepings? Floor sweepings need to put out in the trash. This action is similar to flushing a toilet. It takes a deranged mind to offer strangers waste and expect to be rewarded in return. Oh its not floor sweepings? Then maybe it should not be called a ‘Shack Cleaning Sale’!

Linear amplifier Comparison

Power out – The reading on a watt meter when the amplifier is driven in CW mode with 100 watts on 80 meters into a dummy load.

30L1 and other amps using 4-811 tubes.

The best you can hope for in power out is 800 watts.
The 811 is the least expensive power tube still in production.
A good value at $600. Don’t pay more than $700.

SB-200 and other amps using 572B tubes.

The best you can hope for in power out is 500 to 600 watts.
Beware those claiming 700 watts PEP. That is only 350 watts CW key down and indicates possible soft tubes.
The 572 is still in production and in the $50 price range.

A good value at $300. Don’t pay more than $400.

HT-45, Drake L75

The best you can hope for in power out is 600 to 700 watts.
These and other amps that use a single zero bias triode like the 3-400 and 3-500 are an unsucessful attempt at economy. They are in the same power range as the dual 572 amps. Tube replacement cost for the single tube amp is almost $100 higher than the cost of a pair of 572 with no improvement in performance.

The amps themselves are also priced about $200 more than a comperably capable two tube 572 amp.

Not recommended unless you can find one at salvage value and already have a good final tube.

SB220 dual 3-500 1200+ watts output.

As always price and condition are the most important considerations. Nearly all heathkit equipent was put together by amatuers with a wide spread of capabilities and skill sets. The 220 is over 30 years old. Chances are that if it is still working now it will keep on working.

The main design flaw in the220 has to do with cooling. The 3-500 tube is designed for forced air cooling. That requires blowers, pressurized chassis, and tube chimneys. Heathkit decided to save a few bucks and use an ordinary fan. Well, the fan they used was not all that great. The end result was bad tubes for lack of cooling. Specifically the tube filament pins got hot enough to melt solder.

The 220 can be resurected for about $500 in parts. Since a Good 220 is only worth about $700 max, it would not make sense to pay more than $200 for an old unmodified amp. This assumes a used up amp with soft tubes and electrolytics needing replacement.

Drake L4B is one of the better amps. It is just as capable as thr 220 without the cooling problems of the 220. Drake is one of the few designs that uses forced air cooling as recommended by Eimac.

Kenwood TL-922 is another dual 3-500 amp but it has some very significant design problems. The problems are significant but fairly simple to fix and this amp is a good looking amp that matches the older Kenwood transceivers such as the TS-950.

Then there are a number of Alpha models that offer very high quality and price. Second only to Henry.

The best value for the money is the Collins 30L-1. You can depend on it maintaining its resale value and 811s are the least expensive way of generating serious power

WWII War Surplus Radios

I recently saw an ad offering an ARC-5 receiver for $35. That is a fair price but the days of tube gear and especially WWII war surplus are over.

Today you can buy a 100 watt all mode and all band transceiver for under $300. I know that is nearly ten times the asking price of the ARC-5 but it is a complete station ready to be put on the air.


Helps to have at least one decent antenna. The KT-34 is not just decent, it is super decent.

It boasts four elements but two of them are driven. The two that are driven are phased similar ro an 8JK configuration. Input impedance is high and brought down to 50 ohms with a 4:1 balun. The driven element configuration results in gain as well as broad frequency response. Broad enough to cover the entire frequency range of 20, 15, and 10 meters. It is a tri-band beam but does not use traps. It uses linearly loaded elements to cover the three bands.

My original KT-34 was a project antenna obtained as a mess of assorted parts in a purchase of surplus antenna hardware including a damaged 20 meter single bander and seven sections of Rohn 25 tower.

The beam was reassembled and mounted on a 55 foot tilt over mast. I worked well for over ten years before the linear loading capacitor insulators finally turned to dust.

The antenna was taken down, an M2 upgrade kit was purchased and installed, the antenna was reinstalled to the mast and is now working as well as it ever did.

The KT-34 is priced at $1200 today and it is well worth every penny. A good amplifier will also set you back $1200 but the beam will ‘amplify’ the receive signals as well as the transmitted signal. You get more bang for the buck by investing in the beam first.


OE3RSB, Rudy in Austria, heard him in the middle of 20 meters with a 57 signal. I guess the beam is working because I could not hear him om the dipole.


I never thought I would own a $3800 radio or trade a Collins 30L-1 for it. Come to think of it, I never thought I would own a 30L-1 either. A really nice 30L-1 is worth about $1000. A nice TS-950sd is also worth about $1000. So the trade was probably fair, but I think I got the better end of that deal.

The only complaint I have is I regularly get whistle bit. This thing has too many bells and whistles. I don’t need most of them and sometimes I get confused but this rig is the best I have ever heard on receive and I have never had anything but good reports on transmit. I have had it for about a year now and use it nearly every day.



This is a really good looking, compact, powerful RF amplifier based on a pair of 3-500Z tubes. Some would say ‘if its so good why are there so many 922 on the used market?’ There are different levels of used market. There are used items that are still very useful but where the owner has lost interest. There are used items with minor problems, and there are used items that have been used up. The majority of 922′s offered for sale have been used up and require a significant investment in time and treasure to effect resurrection..

If a seller admits to a power output of less than 1000 watts on any band, you can bet that the tubes are soft. Replacement tubes cost $360. Well, 3-500z’s are not all that great anyway. Actually the tubes are not the problem. The Kenwood design runs the tube filaments at a voltage higher than recommended by the tube manufacturer. Tube life in a 922 is only about 30% of what it should be. In other words you will be replacing tubes three times as often as you would had Kenwood obeyed the tube manufacturers recommendation. Put another way, at todays prices, It will cost you $720 more to run a 922 as compared to running a well designed amp with the same features. History shows that this cost will increase in the future as tube prices rise.

Wait, but that is not all!

Inrush current is great enough to eventually cause on/off switch failure. Total inrush current when turned on is 48 amps. Not sure how much of that is due to HV electrolytics charging as compared to cold filament surge, but I do know it is not good for the on/off switch.

Instability is invited by the high resistance path between tube ground and output tank assemblies ground.

T/R relay is slow enough to cause hot switching. Normally you switch the antenna before turning on the amp by removing cutoff bias. Not so in the 922. It is more fun to watch the sparks fly? The main features of the 922 T/R switch are: hot switching, mechanical noise, and a voltage level guaranteed to fry the PTT line of any modern exciter.

The Kenwood user manual actually has a section on a Spark Suppressor. The spark suppressor is designed to be a sacrificial spark gap to prevent arching the final tank capacitor. They reassure the user that the arching they will hear while running VOX is perfectly normal!!!! While this is definately not normal, leave the spark gap alone. It also protects the bandswitch.

I am not sure if this is a first but it is the first time I have seen a manufacturer officially design in a problem and ask customers to accept that problem as normal. The TL-922A I own had its short comings corrected as well as 10 meter capability restored.

The 922 design is over 20 years old. Those electrolytic filter caps in the HV supply are most likely dried out and have lost a good portion of their ability to store electrical energy. Replacement cost is around $150.

All these problems have solutions. Parts cost to implement solutions to all these problems is about $700 and if you are a less than accomplished technician, you can add $300 in labor costs. Wow, that is $1000 right there! Add the $900 people are asking for their used up amps and we are close to $2000.

Now, if I had nearly $2000 to put down on an amp, would I spend it on trying to correct mistakes of the past or look for something of value like a well designed and maintained Alpha?

If you are a good technician and a fair scrounger, you can resurrect an old 922, ending up with a good 3-500z amp, for under $500. Now if you figure in a used purchase price of $700 for the amp, we are at $1200 total. Can you buy a new (or used) amp in this power class for $1200? I think so but you might not find one as well built mechanically as the 922.

A good 922, one that has been de-fanged and all its problems solved is worth $1000. That means you should not pay more than $500 for an old TL-922 and then only if you are good at fixing things and don’t mind working for free.

This is the reason you see so many TL-922′s on the used market, and since people are asking twice what they are worth, you will probably see more and more of them in the future.

If you can wait five years, you might be able to pick up a used unmodified 922 for under $300. Assuming you can still get a matched pair of 3-500z’s for under $500 at that time, it might be a good inexpensive way to run some serious power.

After using this amp for several weeks I decided to check the input SWR on all bands after I discovered that it was necessary to use a six and a half foot coax cable between the exciter and amplifier to ensure a good match. All bands except 80 meters had SWRs levels below 1.5:1. The SWR on 80/75 meters was 3:1. The schematic of the input circuit had a coil padded with 220pf mica caps on both ends of the coil. The caps in the amp were 120pf mica. Evidently some at Kenwood decided parts is parts when they built this amp. I added mica capacitors to bring the total capacitance up to what was called out in the schematic and the SWR dropped to below 1.5:1 on 80/75 meters.

I understand that modifying this amp voids the warrenty. I guess that s because the manufacturer wants you to use the equipment the way they intended, all screwed up. I am really worried about the warrantee on a factory messed up amp that is over 20 years old!

While considering mods lets remember that over modification is never a cure for over or under engineering. I recently found an article advocating the removal of the interlock switch controlling primary power to the HV transformer. The reason given for this modification was that the switch might fail and limit current to the transformer and cause damage!!!! I guess that person just did not like interlock switches, almost as much as I don’t like modifications that don’t make sense.

Beware of claims like ‘this modification does not effect the amp.’ If that is true then why do the mod?

Buying tools on-line

Don’t do it. I have bought tools on-line twice now. Never again! My last purchase was through Amazon. I ordered some side cutting pliers. By the time they figured in tax and shipping the cost was over $10. The pliers were cheaply made and would not cut. They were side squeezers, not cutters. A complete waste of time, money and patience. I would have been better off flushing a 10 dollar bill down the toilet.

For a consolation prize I bought a good pair of side cutting pliers at Harbor Freight for $2.50. Brick and mortar stores give you a chance to see and try out products before you buy and you don’t have worry about how much the ‘free’ shipping is going to inflate the price of the merchandise.