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this on ebay
Posted: Fri Aug 14, 2015 7:23 pm
by HAZARDFMradio
Found this on ebay whats your thought on this guys
http://m.ebay.com/itm/321831551021?_mwBanner=1
Re: this on ebay
Posted: Fri Aug 14, 2015 8:43 pm
by Shedbuilt
That looks like the one posted here a while back, with a 2N6166 as the final. The 6166 was a horrible device, without any real redeeming features; low gain, extremely fragile etc. If it is a 2N6166, then I'd be very surprised if it will deliver 150W at all - even momentarily. I doubt that it even makes 100W. Motorola rated the 6166 at 100W, but I've seen them blow - even on dummy loads, at far less. It needs something around 20W of drive, possibly more (can't remember exactly), to get anywhere close to 100W out, and if the driver board is delivering 1W or less, it's probably not getting that. I don't know the driver tranny, but it doesn't look particularly gainy on paper. In my opinion and experiences, a reasonably safe limit for the 2N6166, would be around 50W.
Re: this on ebay
Posted: Fri Aug 14, 2015 11:35 pm
by teckniqs
They are OK for the higher frequencies they are made for like 137-174MHz but they are very fragile on band 2. I have had about 75-80w out of one with around 10w drive but they seem to get very hot and they are very inefficient devices.
....I would bet any money that eBay rig is most definitely no more than 100w, absolute tops!!
Re: this on ebay
Posted: Sat Aug 15, 2015 12:07 am
by Shedbuilt
Quite surprised you did as well as that, to be honest. The spec power gain is 6dB (ie 4x) at 150MHz. We used to get a bit more gain on Band II, which is normal. I think we used to get something like about 70 or 80W for about 15W in - depending which end of the band, individual samples of the device, PSU voltage etc, but they seemed to be into gain compression by that point, so driving them harder produced diminishing returns. This was worse at lower voltages, but towards max voltage, they become even more fragile. Yes, they run hot because they're inefficient, and max dissipation is only 117W, which is low for a 100w device
Re: this on ebay
Posted: Sat Aug 15, 2015 3:03 am
by MiXiN
As said, I'm also sure I've seen this image posted here just recently.
It's condition is classed as 'spares or repair', so unless you're a tinkerer it's probably best left alone unless you fancy a challenge with Paypal and expecting a functional or stable unit.
I know next to f' all about RF electronics, but this thing looks like a POS IMO - just knocked together.
Re: this on ebay
Posted: Sat Aug 15, 2015 5:51 pm
by teckniqs
"Returns:
Seller does not offer returns. You are covered by the eBay Money Back Guarantee
if you received an item that is not as described in the listing."
Re: this on ebay
Posted: Mon Aug 17, 2015 10:00 am
by radio-berlin
Stay clear, it looks shit. Honestly I would never charge for that
Re: this on ebay
Posted: Mon Aug 17, 2015 12:06 pm
by Shedbuilt
No output filter either.......
Re: this on ebay
Posted: Mon Aug 17, 2015 9:21 pm
by HAZARDFMradio
Cheers guys dont wana buy it anyways just came across wiles browsing
Re: this on ebay
Posted: Mon Aug 17, 2015 11:27 pm
by teckniqs
I hope you cleaned it off it afterwards....
Re: this on ebay
Posted: Tue Aug 18, 2015 4:12 am
by MiXiN
teckniqs wrote:"Returns:
Seller does not offer returns. You are covered by the eBay Money Back Guarantee
if you received an item that is not as described in the listing."
You're partly correct in that the description that states "no returns" is worthless, however, the condition specifically implies "spares or repair" and not otherwise and recourse becomes difficult or impossuble via eBay or PayPal as it's stated .
My ex Girlfriend of 7 yrs was an employee for PayPal Ireland, and unless things have changed dramatically in the ~2 years we've split I presume things haven't changed. But, maybe they have?
I've bought things off eBay in the past in the hope that I received a working "spares or repair" purchase for a giveaway price (opening a SNAD), so unless things have changed or you fancy fannying around with a Visa chargeback (a bank think), it's probably best avoiding these type of sellers.