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PTEK Transmitters

Currently running 3 PTEK amplifiers, all 400 watt backups. 1 is being used as the solid state IPA for a Continental 816 25 KW rig. The early ones had a woefully inadequate input stage but it could be beefed up to handle over driven inputs from the exciter. Service, when needed has been good, but not cheap. I modified all of ours to run the fans 24/7 from the AC mains rather than just turning on when the output was on. This has helped the heating probelm on the input stages. I understand the newer ones have resolved that input stage problem. Generally happy with the boxes.
 
I recently installed a Gamma 3000 transmitter and exciter on my station. It made a noticeable improvement in our audio quality. It was quite easy to set up and worked exactly as promised. My only negative comment would be the fans. There are a ton of them, and they are quite loud. On the other hand, how else would you cram 3 KW into something about the size of a microwave oven?
 
I take care of a translator that has the 250 watt transmitter. It had to be repaired early on for a minor issue but no complaints since.
 
Had a 25 watt exciter that did great, only problem occured within 6 months of first use with the frequency agility.
 
Chuck said:
I recently installed a Gamma 3000 transmitter and exciter on my station. It made a noticeable improvement in our audio quality. It was quite easy to set up and worked exactly as promised. My only negative comment would be the fans. There are a ton of them, and they are quite loud. On the other hand, how else would you cram 3 KW into something about the size of a microwave oven?
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Just as an update, our first month's electric bill with the PTEK was down about 20% from the previous month when our old transmitter was still in service. It has been nearly 100 degrees every day this last month, so we are definitely in the peak air conditioning season. The PTEK makes a lot less heat, and is somewhat more efficient as well.
 
Only complaint I have is that we once had to return a 500 watt PA deck for repair (some idiot had tried to drive it with 250 watts in an emergency situation in which the exciter was down) due to burned resistors in the input circuitry. I did think that the $990.00 charged us was a bit much for four surface-mount resistors. Then, when we got the amp back, it shut-down anytime the internal temperature exceeded 80° Farenheit. We finally tossed it on a shelf and replaced it with one that actually worked (from another company).
 
Crap

I purchased a new ptek; Failed out of the box. Factory tried to tell me it was my fault. Returned it. Upon reinstall it did same thing. After much arguing, returned a second time. They shipped what they said was a new unit; the cabinet was warped and power would go up and down on it's own. I threatened to sue before finally getting a refund. Never fool with this crap! The British guy at factory is arrogant and unhelpful. Obviously something going on behind the scenes; I found out that they changed their company name around. Flaky!
 
Not dependable

I have purchased a few of them and had nothing but problems with them. My last one to purchase from them, I had to return 3 times before I got one that worked. had it 8 months and had more problem. Sent if off for repair and after it was returned it doesnt work at all. NEVER BUY PTEK. Very undependable.
 
I just borrowed one from another cluster to use as and IPA for an old FM-25k, it worked like a champ for the few weeks I had it till our Harris unit was repaired.
 
Have an FM 3.5K I help take care of that lost it's IPA. Luckily it only needs to make 3 kw. We bypassed the IPA and ran the FX-50 exciter full bore which provides just enough drive to make full power--with some 9 watts reflected.

My inclination is to recommend they purchase some kind of 150 watt exciter, rather than try to get the old IPA (vintage 1981) repaired. Saw a P-Tek 150 watter offered at quite a reasonable price.

Two questions:

1. Some of the older model PTEK transmitters had very sketchy looking power supplies. This was at least a dozen years ago, though. Did you open the box--what does the supply look like?

2. Had to use an RVR 100 watter to drive my Energy-Onix when the IPA died. Big problem was that the RVR was very fussy about the match--kept folding back, couldn't run more than 50 watts. While both the 3.5K and the Energy-Onix are a nominal 50 ohms in--the key word is "nominal." The match drifts, and tuning is tricky. How fussy or tolerant did you find the P-Tek in matching into the final on your 25K?
 
tpt said:
Have an FM 3.5K I help take care of that lost it's IPA. Luckily it only needs to make 3 kw. We bypassed the IPA and ran the FX-50 exciter full bore which provides just enough drive to make full power--with some 9 watts reflected....

... 2. Had to use an RVR 100 watter to drive my Energy-Onix when the IPA died. Big problem was that the RVR was very fussy about the match--kept folding back, couldn't run more than 50 watts. While both the 3.5K and the Energy-Onix are a nominal 50 ohms in--the key word is "nominal." The match drifts, and tuning is tricky. How fussy or tolerant did you find the P-Tek in matching into the final on your 25K?
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I have one of the 300W units that failed recently. I have not had time to take it apart yet, but in the past I have noticed that the design of the rf amp is very similar to most others in the same class. In other words, schematically speaking, most final amps from one brand would work in another, except for the mechanical differences. In the 300W class, generally, these designs use a monolithic dual mosfet like a MRF151g, BLF278 or SD2932 which are all about the same. The most common design calls for them to be driven in such a way that if one half of the fet fails, the amp's power output falls to zero. I don't think it was necessary to design it that way because it is possible to individually test each fet which means that a little bit of redesign should produce a more reliable product.

Anyway, if a pTek exciter won't drive the 3.5k, you might find similar issues with other brands of transmitter, based on the nearly identical designs. A bigger transmitter might be one possible solution since a few extra reflected Watts will be negligable for the higher rated amp.
 
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I wasn't fussy at all since it is 2 25k's combine I did have to lengthen the line feeding the ptek so I had enough room with the regular tuning section. But no more trouble then the outboard Harris IPAs.
 
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