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HF Packer Amp

Just noticed on the yahoo HFPROJECT group that Virgil is offering a special discount on the hf packer amp. I was wondering if many people use one and how would they rate it.
I operate qrp from a summit with the ft817 during an activation but if I have activated the summit previously in the past I may bring the amplifier along. The other option would be to buy a used ft857 but don’t want another transciever sat in the cupboard, especially as I don’t even have a shack or an antenna at home.

Thanks in advance
Graeme

Hi,

I have the older version that is basically the same circuit which I have used for a long time and it has travelled the world. Things to be aware of:

There is no high SWR protection;
It will fail at some point;
You should be confident to build, repair and tinker;
There have been problems with clipping on lower bands (80 metres predominately) as the MOSFET’s were never designed for use as an RF amplifier;
The original MOSFETs supplied by Virgil tend to ok however you need to be careful if you buy replacements from a different vendor.

Other than the above I have found it to be reliable, tolerant to all sorts of battery voltages, it has a good set of switchable filters and is not too heavy with just the right power level to be heard. I always drive mine at 2.5 Watts which gives around 30 Watts out. You can get more, up to 50 Watts, but no one will hear the difference. I take it out in preference to my Tokyo HL-45B and HL-50B which I do not want to get wet and damaged.

Carolyn

I have a homebrew HF PA based on the Packer amp circuit which I have used with my FT-817. I used it to produce about 30W out (agree with Carolyn that 50W will make little difference), it does make a bit of a difference over the 5W of the 817, but to be honest the last times I’ve done HF activations I’ve not bothered with the PA, it makes less than 2 S points difference (OK that may be the crucial edge sometimes!) and since I find HF so much less of a challenge than VHF/UHF/microwaves :wink: I’m happy to leave carrying junk for the higher bands. Must get out on some summits this year!

73
John GM8OTI

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Thanks for the reply Carolyn and the points to be aware of as I am not to confident on the repair/building front this was going to be my project for the year. May be a bit steep in the learning curve, but looking on the yahoo group there seems to be great support for novice builders.

Cheers John for the reply I would be planning to use it static mobile along with the odd activation as the landlord won’t budge on an antenna. I was nearly temepted with the elecraft KXPA100 but seems a bit pricey for my budget.
Spoke to a chap on 2m SSB from the Dumfries area a while ago who was particating in WAB using 2m SSB, forgot to ask how long he has been collecting them for could be a long process.

Thanks for the replies
Graeme

Hello Graeme.

have a look at the small and light chinese PA MX-P50M (10x16x3,5 cm, 515g) too. The output ist about 40-55 watts and it needs about 8A max. I have used this PA with sucess on several SOTA summits together with a FT-817.
You will find a review at https://vk2qr.wordpress.com .
I have bought the PA on ebay for about 180 Euro.

73 Lutz

I have the HardRock50 amp from HobbyPCB. I have used it with my FT-817 and my KX3. It has performed quite well on all SOTA summits. I drive the amp with about 1 W and get about 25 watts out or with 2.4 W and get about 50 Watts out. I also have the ATU kit installed. I love it. Jim Veatch WA2EUJ has been great tech support and everyone at the company has been great to work with. I take it with me on all SOTA trips.
Frank
KD0MQO

I built the HF packer amp a few years ago for SOTA. I found it worked very well within the limits already mentioned.

After a while I realised that it wasn’t really needed on 40m CW and 60m SSB, which is what I was using most of the time.
On the odd occasion I tried 40m SSB however, I found that it helped chasers to hear me through the much higher noise and QRM levels present on that band.

After making up a new battery pack for the FT-817 with modern high capacity Nimhs, I decided to ditch the amp and the SLAB for most of my activations and save a bit of weight.

Ian GW8OGI.

Thanks for the replies MX-P50m looks like the better option for my needs I don’t have a setup at home and was planning on using it from the vehicle parked up during the summer also. I always activate unique summits qrp and would only be using it for returning visits only to the same summits. The KXPA100 looked nice but would struggle sneaking that in to the house past the other half or up a summit, the the price was well above the budget another factor was the pound weakening in the exchange rate.

Another useful review of the mx-p50m http://gm4slv-geek.blogspot.co.uk/2015/03/mx-p50m-amplifier-for-ft817.html

Thanks
Graeme

Would you take a risk on ordering this for the low price £22/€27 posted to the uk.

VAT needs to be paid. Normally you get charged £8.50 or is it £13.50 by the PO for collecting the VAT etc. on imports.

Hi,

have a look on the postage: 159,99 € !

Postage is 5 euros to UK, took a chance £22.90 posted with current exchange rate and thanks for the reminder from Andy £8-£13 VAT bill.

No. They charge the VAT of £4.40. Then they add the collection charge of £8.50 making the total £12.90.

Hi Graeme
I have halved the risk for you!
I have placed order too.
lets wait and see re the VAT.
I have placed many orders from abroad and not been chargd VAT at the level payed including P&P.
Lets hope we throw a double six as I’m sure they throw dice to calculate the amount of Duty and VAT payable
Regards Rowland G4APO

The limit was £15 but may have been lowered recently. Below the limit, they didn’t bother collecting the VAT as it wasn’t cost effective. I found it was random whether they charged it or not. But after having to pay a few £8 charges which exceeded what the VAT would have been I now only buy BY-land bargains from UK shipping centres. I’d like to think the VAT is being collected then.

I was already playing with the idea of getting one of these amplifiers anyway, as it seems to be a nice combination of price/performance/weight. The usual price on eBay and AliExpress is around $200, so it was a bit unexpected to see this appear for €22, and I ordered immediately when I saw your post (thanks!). But maybe it was too good to be true – the seller has contacted me this morning:

sorry, friend, i am very sorry to you you buy this item ,i have connect the
suppliyer , but the supplier say this item is out of store , it is will
appear in somedas later , could you wait some days , when the item is
appear , i will contact you and shipped it to you is it ok . if you have
any problem , pls cotnact me , i will reply you in tim ethanks

Let’s see if it ever arrives, but if not, PayPal buyer protection should take care of it :wink:

I was cancel the purchase - and received a back payment.

I had the same email yesterday from the supplier, noticed this morning it was showing as dispatched. Will be interesting to see what turns up if anything at all.

I did think about cancelling it myself but at that price thought it may be worth a gamble.

The HF packer amp kit is again being promoted with some discounts being offered for builders who purchase at least two of the add on options. see www.hfprojects.com

By pure coincidence I’m currently building an HF Packer too. This is one of the original 2003 vintage ones which I picked up at the local Radio Club Surplus/Junk sale about a month ago. The original owner never got around to building it and I got it for a very good price.

The build is going well and I’m approaching the final assembly stage. Below is a photo of the main RF board.

73, Colin

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